From 7b600d536c6e7d06d204001c844d2fa1bb84e2db Mon Sep 17 00:00:00 2001 From: Derrick Stolee Date: Tue, 23 Feb 2021 09:56:49 -0500 Subject: [PATCH 01/21] sparse-index: design doc and format update This begins a long effort to update the index format to allow sparse directory entries. This should result in a significant improvement to Git commands when HEAD contains millions of files, but the user has selected many fewer files to keep in their sparse-checkout definition. Currently, the index format is only updated in the presence of extensions.sparseIndex instead of increasing a file format version number. This is temporary, and index v5 is part of the plan for future work in this area. The design document details many of the reasons for embarking on this work, and also the plan for completing it safely. Signed-off-by: Derrick Stolee --- Documentation/technical/index-format.txt | 7 + Documentation/technical/sparse-index.txt | 175 +++++++++++++++++++++++ 2 files changed, 182 insertions(+) create mode 100644 Documentation/technical/sparse-index.txt diff --git a/Documentation/technical/index-format.txt b/Documentation/technical/index-format.txt index d363a71c37ec46..3b74c05647dbac 100644 --- a/Documentation/technical/index-format.txt +++ b/Documentation/technical/index-format.txt @@ -44,6 +44,13 @@ Git index format localization, no special casing of directory separator '/'). Entries with the same name are sorted by their stage field. + An index entry typically represents a file. However, if sparse-checkout + is enabled in cone mode (`core.sparseCheckoutCone` is enabled) and the + `extensions.sparseIndex` extension is enabled, then the index may + contain entries for directories outside of the sparse-checkout definition. + These entries have mode `040000`, include the `SKIP_WORKTREE` bit, and + the path ends in a directory separator. + 32-bit ctime seconds, the last time a file's metadata changed this is stat(2) data diff --git a/Documentation/technical/sparse-index.txt b/Documentation/technical/sparse-index.txt new file mode 100644 index 00000000000000..8d3d808046048b --- /dev/null +++ b/Documentation/technical/sparse-index.txt @@ -0,0 +1,175 @@ +Git Sparse-Index Design Document +================================ + +The sparse-checkout feature allows users to focus a working directory on +a subset of the files at HEAD. The cone mode patterns, enabled by +`core.sparseCheckoutCone`, allow for very fast pattern matching to +discover which files at HEAD belong in the sparse-checkout cone. + +Three important scale dimensions for a Git working directory are: + +* `HEAD`: How many files are present at `HEAD`? + +* Populated: How many files are within the sparse-checkout cone. + +* Modified: How many files has the user modified in the working directory? + +We will use big-O notation -- O(X) -- to denote how expensive certain +operations are in terms of these dimensions. + +These dimensions are ordered by their magnitude: users (typically) modify +fewer files than are populated, and we can only populate files at `HEAD`. + +Problems occur if there is an extreme imbalance in these dimensions. For +example, if `HEAD` contains millions of paths but the populated set has +only tens of thousands, then commands like `git status` and `git add` can +be dominated by operations that require O(`HEAD`) operations instead of +O(Populated). Primarily, the cost is in parsing and rewriting the index, +which is filled primarily with files at `HEAD` that are marked with the +`SKIP_WORKTREE` bit. + +The sparse-index intends to take these commands that read and modify the +index from O(`HEAD`) to O(Populated). To do this, we need to modify the +index format in a significant way: add "sparse directory" entries. + +With cone mode patterns, it is possible to detect when an entire +directory will have its contents outside of the sparse-checkout definition. +Instead of listing all of the files it contains as individual entries, a +sparse-index contains an entry with the directory name, referencing the +object ID of the tree at `HEAD` and marked with the `SKIP_WORKTREE` bit. +If we need to discover the details for paths within that directory, we +can parse trees to find that list. + +At time of writing, sparse-directory entries violate expectations about the +index format and its in-memory data structure. There are many consumers in +the codebase that expect to iterate through all of the index entries and +see only files. In fact, these loops expect to see a reference to every +staged file. One way to handle this is to parse trees to replace a +sparse-directory entry with all of the files within that tree as the index +is loaded. However, parsing trees is slower than parsing the index format, +so that is a slower operation than if we left the index alone. The plan is +to make all of these integrations "sparse aware" so this expansion through +tree parsing is unnecessary and they use fewer resources than when using a +full index. + +The implementation plan below follows four phases to slowly integrate with +the sparse-index. The intention is to incrementally update Git commands to +interact safely with the sparse-index without significant slowdowns. This +may not always be possible, but the hope is that the primary commands that +users need in their daily work are dramatically improved. + +Phase I: Format and initial speedups +------------------------------------ + +During this phase, Git learns to enable the sparse-index and safely parse +one. Protections are put in place so that every consumer of the in-memory +data structure can operate with its current assumption of every file at +`HEAD`. + +At first, every index parse will call a helper method, +`ensure_full_index()`, which scans the index for sparse-directory entries +(pointing to trees) and replaces them with the full list of paths (with +blob contents) by parsing tree objects. This will be slower in all cases. +The only noticeable change in behavior will be that the serialized index +file contains sparse-directory entries. + +To start, we use a new required index extension, `sdir`, to allow +inserting sparse-directory entries into indexes with file format +versions 2, 3, and 4. This prevents Git versions that do not understand +the sparse-index from operating on one, while allowing tools that do not +understand the sparse-index to operate on repositories as long as they do +not interact with the index. A new format, index v5, will be introduced +that includes sparse-directory entries by default. It might also +introduce other features that have been considered for improving the +index, as well. + +Next, consumers of the index will be guarded against operating on a +sparse-index by inserting calls to `ensure_full_index()` or +`expand_index_to_path()`. After these guards are in place, we can begin +leaving sparse-directory entries in the in-memory index structure. + +Even after inserting these guards, we will keep expanding sparse-indexes +for most Git commands using the `command_requires_full_index` repository +setting. This setting will be on by default and disabled one builtin at a +time until we have sufficient confidence that all of the index operations +are properly guarded. + +To complete this phase, the commands `git status` and `git add` will be +integrated with the sparse-index so that they operate with O(Populated) +performance. They will be carefully tested for operations within and +outside the sparse-checkout definition. + +Phase II: Careful integrations +------------------------------ + +This phase focuses on ensuring that all index extensions and APIs work +well with a sparse-index. This requires significant increases to our test +coverage, especially for operations that interact with the working +directory outside of the sparse-checkout definition. Some of these +behaviors may not be the desirable ones, such as some tests already +marked for failure in `t1092-sparse-checkout-compatibility.sh`. + +The index extensions that may require special integrations are: + +* FS Monitor +* Untracked cache + +While integrating with these features, we should look for patterns that +might lead to better APIs for interacting with the index. Coalescing +common usage patterns into an API call can reduce the number of places +where sparse-directories need to be handled carefully. + +Phase III: Important command speedups +------------------------------------- + +At this point, the patterns for testing and implementing sparse-directory +logic should be relatively stable. This phase focuses on updating some of +the most common builtins that use the index to operate as O(Populated). +Here is a potential list of commands that could be valuable to integrate +at this point: + +* `git commit` +* `git checkout` +* `git merge` +* `git rebase` + +Hopefully, commands such as `git merge` and `git rebase` can benefit +instead from merge algorithms that do not use the index as a data +structure, such as the merge-ORT strategy. As these topics mature, we +may enable the ORT strategy by default for repositories using the +sparse-index feature. + +Along with `git status` and `git add`, these commands cover the majority +of users' interactions with the working directory. In addition, we can +integrate with these commands: + +* `git grep` +* `git rm` + +These have been proposed as some whose behavior could change when in a +repo with a sparse-checkout definition. It would be good to include this +behavior automatically when using a sparse-index. Some clarity is needed +to make the behavior switch clear to the user. + +This phase is the first where parallel work might be possible without too +much conflicts between topics. + +Phase IV: The long tail +----------------------- + +This last phase is less a "phase" and more "the new normal" after all of +the previous work. + +To start, the `command_requires_full_index` option could be removed in +favor of expanding only when hitting an API guard. + +There are many Git commands that could use special attention to operate as +O(Populated), while some might be so rare that it is acceptable to leave +them with additional overhead when a sparse-index is present. + +Here are some commands that might be useful to update: + +* `git sparse-checkout set` +* `git am` +* `git clean` +* `git stash` From 202253ec82f34d1302ee7360e4d458ac4af89e82 Mon Sep 17 00:00:00 2001 From: Derrick Stolee Date: Mon, 15 Feb 2021 12:18:13 -0500 Subject: [PATCH 02/21] t/perf: add performance test for sparse operations Create a test script that takes the default performance test (the Git codebase) and multiplies it by 256 using four layers of duplicated trees of width four. This results in nearly one million blob entries in the index. Then, we can clone this repository with sparse-checkout patterns that demonstrate four copies of the initial repository. Each clone will use a different index format or mode so peformance can be tested across the different options. Note that the initial repo is stripped of submodules before doing the copies. This preserves the expected data shape of the sparse index, because directories containing submodules are not collapsed to a sparse directory entry. Run a few Git commands on these clones, especially those that use the index (status, add, commit). Here are the results on my Linux machine: Test -------------------------------------------------------------- 2000.2: git status (full-index-v3) 0.37(0.30+0.09) 2000.3: git status (full-index-v4) 0.39(0.32+0.10) 2000.4: git add -A (full-index-v3) 1.42(1.06+0.20) 2000.5: git add -A (full-index-v4) 1.26(0.98+0.16) 2000.6: git add . (full-index-v3) 1.40(1.04+0.18) 2000.7: git add . (full-index-v4) 1.26(0.98+0.17) 2000.8: git commit -a -m A (full-index-v3) 1.42(1.11+0.16) 2000.9: git commit -a -m A (full-index-v4) 1.33(1.08+0.16) It is perhaps noteworthy that there is an improvement when using index version 4. This is because the v3 index uses 108 MiB while the v4 index uses 80 MiB. Since the repeated portions of the directories are very short (f3/f1/f2, for example) this ratio is less pronounced than in similarly-sized real repositories. Signed-off-by: Derrick Stolee --- t/perf/p2000-sparse-operations.sh | 84 +++++++++++++++++++++++++++++++ 1 file changed, 84 insertions(+) create mode 100755 t/perf/p2000-sparse-operations.sh diff --git a/t/perf/p2000-sparse-operations.sh b/t/perf/p2000-sparse-operations.sh new file mode 100755 index 00000000000000..dddd527b633034 --- /dev/null +++ b/t/perf/p2000-sparse-operations.sh @@ -0,0 +1,84 @@ +#!/bin/sh + +test_description="test performance of Git operations using the index" + +. ./perf-lib.sh + +test_perf_default_repo + +SPARSE_CONE=f2/f4/f1 + +test_expect_success 'setup repo and indexes' ' + git reset --hard HEAD && + + # Remove submodules from the example repo, because our + # duplication of the entire repo creates an unlikely data shape. + if git config --file .gitmodules --get-regexp "submodule.*.path" >modules + then + git rm $(awk "{print \$2}" modules) && + git commit -m "remove submodules" || return 1 + fi && + + echo bogus >a && + cp a b && + git add a b && + git commit -m "level 0" && + BLOB=$(git rev-parse HEAD:a) && + OLD_COMMIT=$(git rev-parse HEAD) && + OLD_TREE=$(git rev-parse HEAD^{tree}) && + + for i in $(test_seq 1 4) + do + cat >in <<-EOF && + 100755 blob $BLOB a + 040000 tree $OLD_TREE f1 + 040000 tree $OLD_TREE f2 + 040000 tree $OLD_TREE f3 + 040000 tree $OLD_TREE f4 + EOF + NEW_TREE=$(git mktree >$SPARSE_CONE/a && + $command + ) + " + done +} + +test_perf_on_all git status +test_perf_on_all git add -A +test_perf_on_all git add . +test_perf_on_all git commit -a -m A + +test_done From 437a0f144e57cd4d0811ff652e760cb961b1db1e Mon Sep 17 00:00:00 2001 From: Derrick Stolee Date: Mon, 15 Feb 2021 11:19:59 -0500 Subject: [PATCH 03/21] t1092: clean up script quoting This test was introduced in 19a0acc83e4 (t1092: test interesting sparse-checkout scenarios, 2021-01-23), but it contains issues with quoting that were not noticed until starting this follow-up series. The old mechanism would drop quoting such as in test_all_match git commit -m "touch README.md" The above happened to work because README.md is a file in the repository, so 'git commit -m touch REAMDE.md' would succeed by accident. Other cases included quoting for no good reason, so clean that up now. Signed-off-by: Derrick Stolee --- t/t1092-sparse-checkout-compatibility.sh | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) diff --git a/t/t1092-sparse-checkout-compatibility.sh b/t/t1092-sparse-checkout-compatibility.sh index 8cd3e5a8d2277f..3725d3997e7079 100755 --- a/t/t1092-sparse-checkout-compatibility.sh +++ b/t/t1092-sparse-checkout-compatibility.sh @@ -96,20 +96,20 @@ init_repos () { run_on_sparse () { ( cd sparse-checkout && - $* >../sparse-checkout-out 2>../sparse-checkout-err + "$@" >../sparse-checkout-out 2>../sparse-checkout-err ) } run_on_all () { ( cd full-checkout && - $* >../full-checkout-out 2>../full-checkout-err + "$@" >../full-checkout-out 2>../full-checkout-err ) && - run_on_sparse $* + run_on_sparse "$@" } test_all_match () { - run_on_all $* && + run_on_all "$@" && test_cmp full-checkout-out sparse-checkout-out && test_cmp full-checkout-err sparse-checkout-err } @@ -119,7 +119,7 @@ test_expect_success 'status with options' ' test_all_match git status --porcelain=v2 && test_all_match git status --porcelain=v2 -z -u && test_all_match git status --porcelain=v2 -uno && - run_on_all "touch README.md" && + run_on_all touch README.md && test_all_match git status --porcelain=v2 && test_all_match git status --porcelain=v2 -z -u && test_all_match git status --porcelain=v2 -uno && @@ -135,7 +135,7 @@ test_expect_success 'add, commit, checkout' ' write_script edit-contents <<-\EOF && echo text >>$1 EOF - run_on_all "../edit-contents README.md" && + run_on_all ../edit-contents README.md && test_all_match git add README.md && test_all_match git status --porcelain=v2 && @@ -144,7 +144,7 @@ test_expect_success 'add, commit, checkout' ' test_all_match git checkout HEAD~1 && test_all_match git checkout - && - run_on_all "../edit-contents README.md" && + run_on_all ../edit-contents README.md && test_all_match git add -A && test_all_match git status --porcelain=v2 && @@ -153,7 +153,7 @@ test_expect_success 'add, commit, checkout' ' test_all_match git checkout HEAD~1 && test_all_match git checkout - && - run_on_all "../edit-contents deep/newfile" && + run_on_all ../edit-contents deep/newfile && test_all_match git status --porcelain=v2 -uno && test_all_match git status --porcelain=v2 && @@ -186,7 +186,7 @@ test_expect_success 'diff --staged' ' write_script edit-contents <<-\EOF && echo text >>README.md EOF - run_on_all "../edit-contents" && + run_on_all ../edit-contents && test_all_match git diff && test_all_match git diff --staged && @@ -280,7 +280,7 @@ test_expect_success 'clean' ' echo bogus >>.gitignore && run_on_all cp ../.gitignore . && test_all_match git add .gitignore && - test_all_match git commit -m ignore-bogus-files && + test_all_match git commit -m "ignore bogus files" && run_on_sparse mkdir folder1 && run_on_all touch folder1/bogus && From b7e1bf5c55a72bf3da6cc28583f4a241a4c6253f Mon Sep 17 00:00:00 2001 From: Derrick Stolee Date: Fri, 8 Jan 2021 08:18:25 -0500 Subject: [PATCH 04/21] sparse-index: add guard to ensure full index Upcoming changes will introduce modifications to the index format that allow sparse directories. It will be useful to have a mechanism for converting those sparse index files into full indexes by walking the tree at those sparse directories. Name this method ensure_full_index() as it will guarantee that the index is fully expanded. This method is not implemented yet, and instead we focus on the scaffolding to declare it and call it at the appropriate time. Add a 'command_requires_full_index' member to struct repo_settings. This will be an indicator that we need the index in full mode to do certain index operations. This starts as being true for every command, then we will set it to false as some commands integrate with sparse indexes. If 'command_requires_full_index' is true, then we will immediately expand a sparse index to a full one upon reading from disk. This suffices for now, but we will want to add more callers to ensure_full_index() later. Signed-off-by: Derrick Stolee --- Makefile | 1 + repo-settings.c | 8 ++++++++ repository.c | 11 ++++++++++- repository.h | 2 ++ sparse-index.c | 8 ++++++++ sparse-index.h | 7 +++++++ 6 files changed, 36 insertions(+), 1 deletion(-) create mode 100644 sparse-index.c create mode 100644 sparse-index.h diff --git a/Makefile b/Makefile index dfb0f1000fa311..89b1d5374107b3 100644 --- a/Makefile +++ b/Makefile @@ -985,6 +985,7 @@ LIB_OBJS += setup.o LIB_OBJS += shallow.o LIB_OBJS += sideband.o LIB_OBJS += sigchain.o +LIB_OBJS += sparse-index.o LIB_OBJS += split-index.o LIB_OBJS += stable-qsort.o LIB_OBJS += strbuf.o diff --git a/repo-settings.c b/repo-settings.c index f7fff0f5ab837e..d63569e4041eca 100644 --- a/repo-settings.c +++ b/repo-settings.c @@ -77,4 +77,12 @@ void prepare_repo_settings(struct repository *r) UPDATE_DEFAULT_BOOL(r->settings.core_untracked_cache, UNTRACKED_CACHE_KEEP); UPDATE_DEFAULT_BOOL(r->settings.fetch_negotiation_algorithm, FETCH_NEGOTIATION_DEFAULT); + + /* + * This setting guards all index reads to require a full index + * over a sparse index. After suitable guards are placed in the + * codebase around uses of the index, this setting will be + * removed. + */ + r->settings.command_requires_full_index = 1; } diff --git a/repository.c b/repository.c index c98298acd017b5..a8acae002f712c 100644 --- a/repository.c +++ b/repository.c @@ -10,6 +10,7 @@ #include "object.h" #include "lockfile.h" #include "submodule-config.h" +#include "sparse-index.h" /* The main repository */ static struct repository the_repo; @@ -261,6 +262,8 @@ void repo_clear(struct repository *repo) int repo_read_index(struct repository *repo) { + int res; + if (!repo->index) repo->index = xcalloc(1, sizeof(*repo->index)); @@ -270,7 +273,13 @@ int repo_read_index(struct repository *repo) else if (repo->index->repo != repo) BUG("repo's index should point back at itself"); - return read_index_from(repo->index, repo->index_file, repo->gitdir); + res = read_index_from(repo->index, repo->index_file, repo->gitdir); + + prepare_repo_settings(repo); + if (repo->settings.command_requires_full_index) + ensure_full_index(repo->index); + + return res; } int repo_hold_locked_index(struct repository *repo, diff --git a/repository.h b/repository.h index b385ca3c94b62b..e06a2301569722 100644 --- a/repository.h +++ b/repository.h @@ -41,6 +41,8 @@ struct repo_settings { enum fetch_negotiation_setting fetch_negotiation_algorithm; int core_multi_pack_index; + + unsigned command_requires_full_index:1; }; struct repository { diff --git a/sparse-index.c b/sparse-index.c new file mode 100644 index 00000000000000..82183ead563b98 --- /dev/null +++ b/sparse-index.c @@ -0,0 +1,8 @@ +#include "cache.h" +#include "repository.h" +#include "sparse-index.h" + +void ensure_full_index(struct index_state *istate) +{ + /* intentionally left blank */ +} diff --git a/sparse-index.h b/sparse-index.h new file mode 100644 index 00000000000000..09a20d036c4621 --- /dev/null +++ b/sparse-index.h @@ -0,0 +1,7 @@ +#ifndef SPARSE_INDEX_H__ +#define SPARSE_INDEX_H__ + +struct index_state; +void ensure_full_index(struct index_state *istate); + +#endif From e41d55d2cca906af2f11265de4d8977b1881219e Mon Sep 17 00:00:00 2001 From: Derrick Stolee Date: Fri, 8 Jan 2021 08:30:04 -0500 Subject: [PATCH 05/21] sparse-index: implement ensure_full_index() We will mark an in-memory index_state as having sparse directory entries with the sparse_index bit. These currently cannot exist, but we will add a mechanism for collapsing a full index to a sparse one in a later change. That will happen at write time, so we must first allow parsing the format before writing it. Commands or methods that require a full index in order to operate can call ensure_full_index() to expand that index in-memory. This requires parsing trees using that index's repository. Sparse directory entries have a specific 'ce_mode' value. The macro S_ISSPARSEDIR(ce->ce_mode) can check if a cache_entry 'ce' has this type. This ce_mode is not possible with the existing index formats, so we don't also verify all properties of a sparse-directory entry, which are: 1. ce->ce_mode == 0040000 2. ce->flags & CE_SKIP_WORKTREE is true 3. ce->name[ce->namelen - 1] == '/' (ends in dir separator) 4. ce->oid references a tree object. These are all semi-enforced in ensure_full_index() to some extent. Any deviation will cause a warning at minimum or a failure in the worst case. Signed-off-by: Derrick Stolee --- cache.h | 13 ++++++- read-cache.c | 9 +++++ sparse-index.c | 98 +++++++++++++++++++++++++++++++++++++++++++++++++- 3 files changed, 118 insertions(+), 2 deletions(-) diff --git a/cache.h b/cache.h index bb317abc91fbc1..136dd496c95db8 100644 --- a/cache.h +++ b/cache.h @@ -204,6 +204,8 @@ struct cache_entry { #error "CE_EXTENDED_FLAGS out of range" #endif +#define S_ISSPARSEDIR(m) ((m) == S_IFDIR) + /* Forward structure decls */ struct pathspec; struct child_process; @@ -319,7 +321,14 @@ struct index_state { drop_cache_tree : 1, updated_workdir : 1, updated_skipworktree : 1, - fsmonitor_has_run_once : 1; + fsmonitor_has_run_once : 1, + + /* + * sparse_index == 1 when sparse-directory + * entries exist. Requires sparse-checkout + * in cone mode. + */ + sparse_index : 1; struct hashmap name_hash; struct hashmap dir_hash; struct object_id oid; @@ -722,6 +731,8 @@ int read_index_from(struct index_state *, const char *path, const char *gitdir); int is_index_unborn(struct index_state *); +void ensure_full_index(struct index_state *istate); + /* For use with `write_locked_index()`. */ #define COMMIT_LOCK (1 << 0) #define SKIP_IF_UNCHANGED (1 << 1) diff --git a/read-cache.c b/read-cache.c index 1e9a50c6c73437..dd3980c12b5384 100644 --- a/read-cache.c +++ b/read-cache.c @@ -101,6 +101,9 @@ static const char *alternate_index_output; static void set_index_entry(struct index_state *istate, int nr, struct cache_entry *ce) { + if (S_ISSPARSEDIR(ce->ce_mode)) + istate->sparse_index = 1; + istate->cache[nr] = ce; add_name_hash(istate, ce); } @@ -2273,6 +2276,12 @@ int do_read_index(struct index_state *istate, const char *path, int must_exist) trace2_data_intmax("index", the_repository, "read/cache_nr", istate->cache_nr); + if (!istate->repo) + istate->repo = the_repository; + prepare_repo_settings(istate->repo); + if (istate->repo->settings.command_requires_full_index) + ensure_full_index(istate); + return istate->cache_nr; unmap: diff --git a/sparse-index.c b/sparse-index.c index 82183ead563b98..7095378a1b287a 100644 --- a/sparse-index.c +++ b/sparse-index.c @@ -1,8 +1,104 @@ #include "cache.h" #include "repository.h" #include "sparse-index.h" +#include "tree.h" +#include "pathspec.h" +#include "trace2.h" + +static void set_index_entry(struct index_state *istate, int nr, struct cache_entry *ce) +{ + ALLOC_GROW(istate->cache, nr + 1, istate->cache_alloc); + + istate->cache[nr] = ce; + add_name_hash(istate, ce); +} + +static int add_path_to_index(const struct object_id *oid, + struct strbuf *base, const char *path, + unsigned int mode, void *context) +{ + struct index_state *istate = (struct index_state *)context; + struct cache_entry *ce; + size_t len = base->len; + + if (S_ISDIR(mode)) + return READ_TREE_RECURSIVE; + + strbuf_addstr(base, path); + + ce = make_cache_entry(istate, mode, oid, base->buf, 0, 0); + ce->ce_flags |= CE_SKIP_WORKTREE; + set_index_entry(istate, istate->cache_nr++, ce); + + strbuf_setlen(base, len); + return 0; +} void ensure_full_index(struct index_state *istate) { - /* intentionally left blank */ + int i; + struct index_state *full; + struct strbuf base = STRBUF_INIT; + + if (!istate || !istate->sparse_index) + return; + + if (!istate->repo) + istate->repo = the_repository; + + trace2_region_enter("index", "ensure_full_index", istate->repo); + + /* initialize basics of new index */ + full = xcalloc(1, sizeof(struct index_state)); + memcpy(full, istate, sizeof(struct index_state)); + + /* then change the necessary things */ + full->sparse_index = 0; + full->cache_alloc = (3 * istate->cache_alloc) / 2; + full->cache_nr = 0; + ALLOC_ARRAY(full->cache, full->cache_alloc); + + for (i = 0; i < istate->cache_nr; i++) { + struct cache_entry *ce = istate->cache[i]; + struct tree *tree; + struct pathspec ps; + + if (!S_ISSPARSEDIR(ce->ce_mode)) { + set_index_entry(full, full->cache_nr++, ce); + continue; + } + if (!(ce->ce_flags & CE_SKIP_WORKTREE)) + warning(_("index entry is a directory, but not sparse (%08x)"), + ce->ce_flags); + + /* recursively walk into cd->name */ + tree = lookup_tree(istate->repo, &ce->oid); + + memset(&ps, 0, sizeof(ps)); + ps.recursive = 1; + ps.has_wildcard = 1; + ps.max_depth = -1; + + strbuf_setlen(&base, 0); + strbuf_add(&base, ce->name, strlen(ce->name)); + + read_tree_at(istate->repo, tree, &base, &ps, + add_path_to_index, full); + + /* free directory entries. full entries are re-used */ + discard_cache_entry(ce); + } + + /* Copy back into original index. */ + memcpy(&istate->name_hash, &full->name_hash, sizeof(full->name_hash)); + istate->sparse_index = 0; + free(istate->cache); + istate->cache = full->cache; + istate->cache_nr = full->cache_nr; + istate->cache_alloc = full->cache_alloc; + + strbuf_release(&base); + free(full); + + trace2_region_leave("index", "ensure_full_index", istate->repo); } From 7bfbfbd17321942f8f3a9b799eeb09bf1c58a947 Mon Sep 17 00:00:00 2001 From: Derrick Stolee Date: Fri, 15 Jan 2021 10:10:05 -0500 Subject: [PATCH 06/21] t1092: compare sparse-checkout to sparse-index Add a new 'sparse-index' repo alongside the 'full-checkout' and 'sparse-checkout' repos in t1092-sparse-checkout-compatibility.sh. Also add run_on_sparse and test_sparse_match helpers. These helpers will be used when the sparse index is implemented. Add the GIT_TEST_SPARSE_INDEX environment variable to enable the sparse-index by default. This can be enabled across all tests, but that will only affect cases where the sparse-checkout feature is enabled. Signed-off-by: Derrick Stolee --- t/README | 3 +++ t/t1092-sparse-checkout-compatibility.sh | 24 ++++++++++++++++++++---- 2 files changed, 23 insertions(+), 4 deletions(-) diff --git a/t/README b/t/README index 593d4a4e270cc0..b98bc563aab5bd 100644 --- a/t/README +++ b/t/README @@ -439,6 +439,9 @@ and "sha256". GIT_TEST_WRITE_REV_INDEX=, when true enables the 'pack.writeReverseIndex' setting. +GIT_TEST_SPARSE_INDEX=, when true enables index writes to use the +sparse-index format by default. + Naming Tests ------------ diff --git a/t/t1092-sparse-checkout-compatibility.sh b/t/t1092-sparse-checkout-compatibility.sh index 3725d3997e7079..de5d8461c993cc 100755 --- a/t/t1092-sparse-checkout-compatibility.sh +++ b/t/t1092-sparse-checkout-compatibility.sh @@ -7,6 +7,7 @@ test_description='compare full workdir to sparse workdir' test_expect_success 'setup' ' git init initial-repo && ( + GIT_TEST_SPARSE_INDEX=0 && cd initial-repo && echo a >a && echo "after deep" >e && @@ -87,23 +88,32 @@ init_repos () { cp -r initial-repo sparse-checkout && git -C sparse-checkout reset --hard && - git -C sparse-checkout sparse-checkout init --cone && + + cp -r initial-repo sparse-index && + git -C sparse-index reset --hard && # initialize sparse-checkout definitions - git -C sparse-checkout sparse-checkout set deep + git -C sparse-checkout sparse-checkout init --cone && + git -C sparse-checkout sparse-checkout set deep && + GIT_TEST_SPARSE_INDEX=1 git -C sparse-index sparse-checkout init --cone && + GIT_TEST_SPARSE_INDEX=1 git -C sparse-index sparse-checkout set deep } run_on_sparse () { ( cd sparse-checkout && - "$@" >../sparse-checkout-out 2>../sparse-checkout-err + GIT_TEST_SPARSE_INDEX=0 "$@" >../sparse-checkout-out 2>../sparse-checkout-err + ) && + ( + cd sparse-index && + GIT_TEST_SPARSE_INDEX=1 "$@" >../sparse-index-out 2>../sparse-index-err ) } run_on_all () { ( cd full-checkout && - "$@" >../full-checkout-out 2>../full-checkout-err + GIT_TEST_SPARSE_INDEX=0 "$@" >../full-checkout-out 2>../full-checkout-err ) && run_on_sparse "$@" } @@ -114,6 +124,12 @@ test_all_match () { test_cmp full-checkout-err sparse-checkout-err } +test_sparse_match () { + run_on_sparse "$@" && + test_cmp sparse-checkout-out sparse-index-out && + test_cmp sparse-checkout-err sparse-index-err +} + test_expect_success 'status with options' ' init_repos && test_all_match git status --porcelain=v2 && From a1b8135c0fc890b2c2c0271c923b2f8efa8d1465 Mon Sep 17 00:00:00 2001 From: Derrick Stolee Date: Fri, 18 Dec 2020 08:57:51 -0500 Subject: [PATCH 07/21] test-read-cache: print cache entries with --table This table is helpful for discovering data in the index to ensure it is being written correctly, especially as we build and test the sparse-index. This table includes an output format similar to 'git ls-tree', but should not be compared to that directly. The biggest reasons are that 'git ls-tree' includes a tree entry for every subdirectory, even those that would not appear as a sparse directory in a sparse-index. Further, 'git ls-tree' does not use a trailing directory separator for its tree rows. This does not print the stat() information for the blobs. That will be added in a future change with another option. The tests that are added in the next few changes care only about the object types and IDs. However, this future need for full index information justifies the need for this test helper over extending a user-facing feature, such as 'git ls-files'. To make the option parsing slightly more robust, wrap the string comparisons in a loop adapted from test-dir-iterator.c. Care must be taken with the final check for the 'cnt' variable. We continue the expectation that the numerical value is the final argument. Signed-off-by: Derrick Stolee --- t/helper/test-read-cache.c | 55 +++++++++++++++++++++++++++++++------- 1 file changed, 45 insertions(+), 10 deletions(-) diff --git a/t/helper/test-read-cache.c b/t/helper/test-read-cache.c index 244977a29bdfda..6cfd8f2de71cb2 100644 --- a/t/helper/test-read-cache.c +++ b/t/helper/test-read-cache.c @@ -1,36 +1,71 @@ #include "test-tool.h" #include "cache.h" #include "config.h" +#include "blob.h" +#include "commit.h" +#include "tree.h" + +static void print_cache_entry(struct cache_entry *ce) +{ + const char *type; + printf("%06o ", ce->ce_mode & 0177777); + + if (S_ISSPARSEDIR(ce->ce_mode)) + type = tree_type; + else if (S_ISGITLINK(ce->ce_mode)) + type = commit_type; + else + type = blob_type; + + printf("%s %s\t%s\n", + type, + oid_to_hex(&ce->oid), + ce->name); +} + +static void print_cache(struct index_state *istate) +{ + int i; + for (i = 0; i < istate->cache_nr; i++) + print_cache_entry(istate->cache[i]); +} int cmd__read_cache(int argc, const char **argv) { + struct repository *r = the_repository; int i, cnt = 1; const char *name = NULL; + int table = 0; - if (argc > 1 && skip_prefix(argv[1], "--print-and-refresh=", &name)) { - argc--; - argv++; + for (++argv, --argc; *argv && starts_with(*argv, "--"); ++argv, --argc) { + if (skip_prefix(*argv, "--print-and-refresh=", &name)) + continue; + if (!strcmp(*argv, "--table")) + table = 1; } - if (argc == 2) - cnt = strtol(argv[1], NULL, 0); + if (argc == 1) + cnt = strtol(argv[0], NULL, 0); setup_git_directory(); git_config(git_default_config, NULL); + for (i = 0; i < cnt; i++) { - read_cache(); + repo_read_index(r); if (name) { int pos; - refresh_index(&the_index, REFRESH_QUIET, + refresh_index(r->index, REFRESH_QUIET, NULL, NULL, NULL); - pos = index_name_pos(&the_index, name, strlen(name)); + pos = index_name_pos(r->index, name, strlen(name)); if (pos < 0) die("%s not in index", name); printf("%s is%s up to date\n", name, - ce_uptodate(the_index.cache[pos]) ? "" : " not"); + ce_uptodate(r->index->cache[pos]) ? "" : " not"); write_file(name, "%d\n", i); } - discard_cache(); + if (table) + print_cache(r->index); + discard_index(r->index); } return 0; } From dd84a2a9121b52c4b9bf0a52d6e52f3e40075c6f Mon Sep 17 00:00:00 2001 From: Derrick Stolee Date: Thu, 7 Jan 2021 11:29:04 -0500 Subject: [PATCH 08/21] test-tool: don't force full index We will use 'test-tool read-cache --table' to check that a sparse index is written as part of init_repos. Since we will no longer always expand a sparse index into a full index, add an '--expand' parameter that adds a call to ensure_full_index() so we can compare a sparse index directly against a full index, or at least what the in-memory index looks like when expanded in this way. Signed-off-by: Derrick Stolee --- t/helper/test-read-cache.c | 13 ++++++++++++- t/t1092-sparse-checkout-compatibility.sh | 5 +++++ 2 files changed, 17 insertions(+), 1 deletion(-) diff --git a/t/helper/test-read-cache.c b/t/helper/test-read-cache.c index 6cfd8f2de71cb2..b52c174acc7a1f 100644 --- a/t/helper/test-read-cache.c +++ b/t/helper/test-read-cache.c @@ -4,6 +4,7 @@ #include "blob.h" #include "commit.h" #include "tree.h" +#include "sparse-index.h" static void print_cache_entry(struct cache_entry *ce) { @@ -35,13 +36,19 @@ int cmd__read_cache(int argc, const char **argv) struct repository *r = the_repository; int i, cnt = 1; const char *name = NULL; - int table = 0; + int table = 0, expand = 0; + + initialize_the_repository(); + prepare_repo_settings(r); + r->settings.command_requires_full_index = 0; for (++argv, --argc; *argv && starts_with(*argv, "--"); ++argv, --argc) { if (skip_prefix(*argv, "--print-and-refresh=", &name)) continue; if (!strcmp(*argv, "--table")) table = 1; + else if (!strcmp(*argv, "--expand")) + expand = 1; } if (argc == 1) @@ -51,6 +58,10 @@ int cmd__read_cache(int argc, const char **argv) for (i = 0; i < cnt; i++) { repo_read_index(r); + + if (expand) + ensure_full_index(r->index); + if (name) { int pos; diff --git a/t/t1092-sparse-checkout-compatibility.sh b/t/t1092-sparse-checkout-compatibility.sh index de5d8461c993cc..a1aea141c62cc7 100755 --- a/t/t1092-sparse-checkout-compatibility.sh +++ b/t/t1092-sparse-checkout-compatibility.sh @@ -130,6 +130,11 @@ test_sparse_match () { test_cmp sparse-checkout-err sparse-index-err } +test_expect_success 'expanded in-memory index matches full index' ' + init_repos && + test_sparse_match test-tool read-cache --expand --table +' + test_expect_success 'status with options' ' init_repos && test_all_match git status --porcelain=v2 && From b276d2ed53238465b1416676a58506414022860f Mon Sep 17 00:00:00 2001 From: Derrick Stolee Date: Tue, 19 Jan 2021 11:01:57 -0500 Subject: [PATCH 09/21] unpack-trees: ensure full index The next change will translate full indexes into sparse indexes at write time. The existing logic provides a way for every sparse index to be expanded to a full index at read time. However, there are cases where an index is written and then continues to be used in-memory to perform further updates. unpack_trees() is frequently called after such a write. In particular, commands like 'git reset' do this double-update of the index. Ensure that we have a full index when entering unpack_trees(), but only when command_requires_full_index is true. This is always true at the moment, but we will later relax that after unpack_trees() is updated to handle sparse directory entries. Signed-off-by: Derrick Stolee --- unpack-trees.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/unpack-trees.c b/unpack-trees.c index f5f668f532d8d5..4dd99219073a4f 100644 --- a/unpack-trees.c +++ b/unpack-trees.c @@ -1567,6 +1567,7 @@ static int verify_absent(const struct cache_entry *, */ int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options *o) { + struct repository *repo = the_repository; int i, ret; static struct cache_entry *dfc; struct pattern_list pl; @@ -1578,6 +1579,12 @@ int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options trace_performance_enter(); trace2_region_enter("unpack_trees", "unpack_trees", the_repository); + prepare_repo_settings(repo); + if (repo->settings.command_requires_full_index) { + ensure_full_index(o->src_index); + ensure_full_index(o->dst_index); + } + if (!core_apply_sparse_checkout || !o->update) o->skip_sparse_checkout = 1; if (!o->skip_sparse_checkout && !o->pl) { From c3651e26dc3ace4602eeb7c7bbe3ee15684de257 Mon Sep 17 00:00:00 2001 From: Derrick Stolee Date: Tue, 12 Jan 2021 08:44:24 -0500 Subject: [PATCH 10/21] sparse-checkout: hold pattern list in index As we modify the sparse-checkout definition, we perform index operations on a pattern_list that only exists in-memory. This allows easy backing out in case the index update fails. However, if the index write itself cares about the sparse-checkout pattern set, we need access to that in-memory copy. Place a pointer to a 'struct pattern_list' in the index so we can access this on-demand. This will be used in the next change which uses the sparse-checkout definition to filter out directories that are outside the sparse cone. Signed-off-by: Derrick Stolee --- builtin/sparse-checkout.c | 17 ++++++++++------- cache.h | 2 ++ 2 files changed, 12 insertions(+), 7 deletions(-) diff --git a/builtin/sparse-checkout.c b/builtin/sparse-checkout.c index 2306a9ad98e08a..e00b82af727b5d 100644 --- a/builtin/sparse-checkout.c +++ b/builtin/sparse-checkout.c @@ -110,6 +110,8 @@ static int update_working_directory(struct pattern_list *pl) if (is_index_unborn(r->index)) return UPDATE_SPARSITY_SUCCESS; + r->index->sparse_checkout_patterns = pl; + memset(&o, 0, sizeof(o)); o.verbose_update = isatty(2); o.update = 1; @@ -138,6 +140,7 @@ static int update_working_directory(struct pattern_list *pl) else rollback_lock_file(&lock_file); + r->index->sparse_checkout_patterns = NULL; return result; } @@ -517,19 +520,18 @@ static int modify_pattern_list(int argc, const char **argv, enum modify_type m) { int result; int changed_config = 0; - struct pattern_list pl; - memset(&pl, 0, sizeof(pl)); + struct pattern_list *pl = xcalloc(1, sizeof(*pl)); switch (m) { case ADD: if (core_sparse_checkout_cone) - add_patterns_cone_mode(argc, argv, &pl); + add_patterns_cone_mode(argc, argv, pl); else - add_patterns_literal(argc, argv, &pl); + add_patterns_literal(argc, argv, pl); break; case REPLACE: - add_patterns_from_input(&pl, argc, argv); + add_patterns_from_input(pl, argc, argv); break; } @@ -539,12 +541,13 @@ static int modify_pattern_list(int argc, const char **argv, enum modify_type m) changed_config = 1; } - result = write_patterns_and_update(&pl); + result = write_patterns_and_update(pl); if (result && changed_config) set_config(MODE_NO_PATTERNS); - clear_pattern_list(&pl); + clear_pattern_list(pl); + free(pl); return result; } diff --git a/cache.h b/cache.h index 136dd496c95db8..8c4464420d0a49 100644 --- a/cache.h +++ b/cache.h @@ -307,6 +307,7 @@ static inline unsigned int canon_mode(unsigned int mode) struct split_index; struct untracked_cache; struct progress; +struct pattern_list; struct index_state { struct cache_entry **cache; @@ -338,6 +339,7 @@ struct index_state { struct mem_pool *ce_mem_pool; struct progress *progress; struct repository *repo; + struct pattern_list *sparse_checkout_patterns; }; /* Name hashing */ From f926cf8b2e019c710e164521bf90f7d948c7aa3d Mon Sep 17 00:00:00 2001 From: Derrick Stolee Date: Mon, 29 Mar 2021 14:36:46 -0400 Subject: [PATCH 11/21] sparse-index: add 'sdir' index extension The index format does not currently allow for sparse directory entries. This violates some expectations that older versions of Git or third-party tools might not understand. We need an indicator inside the index file to warn these tools to not interact with a sparse index unless they are aware of sparse directory entries. Add a new _required_ index extension, 'sdir', that indicates that the index may contain sparse directory entries. This allows us to continue to use the differences in index formats 2, 3, and 4 before we create a new index version 5 in a later change. Signed-off-by: Derrick Stolee --- Documentation/technical/index-format.txt | 12 ++++++++++++ read-cache.c | 9 +++++++++ 2 files changed, 21 insertions(+) diff --git a/Documentation/technical/index-format.txt b/Documentation/technical/index-format.txt index 3b74c05647dbac..65da0daaa5634c 100644 --- a/Documentation/technical/index-format.txt +++ b/Documentation/technical/index-format.txt @@ -392,3 +392,15 @@ The remaining data of each directory block is grouped by type: in this block of entries. - 32-bit count of cache entries in this block + +== Sparse Directory Entries + + When using sparse-checkout in cone mode, some entire directories within + the index can be summarized by pointing to a tree object instead of the + entire expanded list of paths within that tree. An index containing such + entries is a "sparse index". Index format versions 4 and less were not + implemented with such entries in mind. Thus, for these versions, an + index containing sparse directory entries will include this extension + with signature { 's', 'd', 'i', 'r' }. Like the split-index extension, + tools should avoid interacting with a sparse index unless they understand + this extension. diff --git a/read-cache.c b/read-cache.c index dd3980c12b5384..b8f092d1b7eb7d 100644 --- a/read-cache.c +++ b/read-cache.c @@ -47,6 +47,7 @@ #define CACHE_EXT_FSMONITOR 0x46534D4E /* "FSMN" */ #define CACHE_EXT_ENDOFINDEXENTRIES 0x454F4945 /* "EOIE" */ #define CACHE_EXT_INDEXENTRYOFFSETTABLE 0x49454F54 /* "IEOT" */ +#define CACHE_EXT_SPARSE_DIRECTORIES 0x73646972 /* "sdir" */ /* changes that can be kept in $GIT_DIR/index (basically all extensions) */ #define EXTMASK (RESOLVE_UNDO_CHANGED | CACHE_TREE_CHANGED | \ @@ -1763,6 +1764,10 @@ static int read_index_extension(struct index_state *istate, case CACHE_EXT_INDEXENTRYOFFSETTABLE: /* already handled in do_read_index() */ break; + case CACHE_EXT_SPARSE_DIRECTORIES: + /* no content, only an indicator */ + istate->sparse_index = 1; + break; default: if (*ext < 'A' || 'Z' < *ext) return error(_("index uses %.4s extension, which we do not understand"), @@ -3020,6 +3025,10 @@ static int do_write_index(struct index_state *istate, struct tempfile *tempfile, if (err) return -1; } + if (istate->sparse_index) { + if (write_index_ext_header(&c, &eoie_c, newfd, CACHE_EXT_SPARSE_DIRECTORIES, 0) < 0) + return -1; + } /* * CACHE_EXT_ENDOFINDEXENTRIES must be written as the last entry before the SHA1 From c870ae5e8749bb04c1290b607607ac056552e3f9 Mon Sep 17 00:00:00 2001 From: Derrick Stolee Date: Fri, 8 Jan 2021 08:38:34 -0500 Subject: [PATCH 12/21] sparse-index: convert from full to sparse If we have a full index, then we can convert it to a sparse index by replacing directories outside of the sparse cone with sparse directory entries. The convert_to_sparse() method does this, when the situation is appropriate. For now, we avoid converting the index to a sparse index if: 1. the index is split. 2. the index is already sparse. 3. sparse-checkout is disabled. 4. sparse-checkout does not use cone mode. Finally, we currently limit the conversion to when the GIT_TEST_SPARSE_INDEX environment variable is enabled. A mode using Git config will be added in a later change. The trickiest thing about this conversion is that we might not be able to mark a directory as a sparse directory just because it is outside the sparse cone. There might be unmerged files within that directory, so we need to look for those. Also, if there is some strange reason why a file is not marked with CE_SKIP_WORKTREE, then we should give up on converting that directory. There is still hope that some of its subdirectories might be able to convert to sparse, so we keep looking deeper. The conversion process is assisted by the cache-tree extension. This is calculated from the full index if it does not already exist. We then abandon the cache-tree as it no longer applies to the newly-sparse index. Thus, this cache-tree will be recalculated in every sparse-full-sparse round-trip until we integrate the cache-tree extension with the sparse index. Some Git commands use the index after writing it. For example, 'git add' will update the index, then write it to disk, then read its entries to report information. To keep the in-memory index in a full state after writing, we re-expand it to a full one after the write. This is wasteful for commands that only write the index and do not read from it again, but that is only the case until we make those commands "sparse aware." We can compare the behavior of the sparse-index in t1092-sparse-checkout-compability.sh by using GIT_TEST_SPARSE_INDEX=1 when operating on the 'sparse-index' repo. We can also compare the two sparse repos directly, such as comparing their indexes (when expanded to full in the case of the 'sparse-index' repo). We also verify that the index is actually populated with sparse directory entries. The 'checkout and reset (mixed)' test is marked for failure when comparing a sparse repo to a full repo, but we can compare the two sparse-checkout cases directly to ensure that we are not changing the behavior when using a sparse index. Signed-off-by: Derrick Stolee --- cache-tree.c | 3 + cache.h | 2 + read-cache.c | 26 ++++- sparse-index.c | 139 +++++++++++++++++++++++ sparse-index.h | 1 + t/t1092-sparse-checkout-compatibility.sh | 61 +++++++++- 6 files changed, 228 insertions(+), 4 deletions(-) diff --git a/cache-tree.c b/cache-tree.c index 2fb483d3c08389..5f07a39e501e63 100644 --- a/cache-tree.c +++ b/cache-tree.c @@ -6,6 +6,7 @@ #include "object-store.h" #include "replace-object.h" #include "promisor-remote.h" +#include "sparse-index.h" #ifndef DEBUG_CACHE_TREE #define DEBUG_CACHE_TREE 0 @@ -442,6 +443,8 @@ int cache_tree_update(struct index_state *istate, int flags) if (i) return i; + ensure_full_index(istate); + if (!istate->cache_tree) istate->cache_tree = cache_tree(); diff --git a/cache.h b/cache.h index 8c4464420d0a49..74b43aaa2bd14f 100644 --- a/cache.h +++ b/cache.h @@ -251,6 +251,8 @@ static inline unsigned int create_ce_mode(unsigned int mode) { if (S_ISLNK(mode)) return S_IFLNK; + if (S_ISSPARSEDIR(mode)) + return S_IFDIR; if (S_ISDIR(mode) || S_ISGITLINK(mode)) return S_IFGITLINK; return S_IFREG | ce_permissions(mode); diff --git a/read-cache.c b/read-cache.c index b8f092d1b7eb7d..2410e6e0df13ca 100644 --- a/read-cache.c +++ b/read-cache.c @@ -25,6 +25,7 @@ #include "fsmonitor.h" #include "thread-utils.h" #include "progress.h" +#include "sparse-index.h" /* Mask for the name length in ce_flags in the on-disk index */ @@ -1003,8 +1004,14 @@ int verify_path(const char *path, unsigned mode) c = *path++; if ((c == '.' && !verify_dotfile(path, mode)) || - is_dir_sep(c) || c == '\0') + is_dir_sep(c)) return 0; + /* + * allow terminating directory separators for + * sparse directory entries. + */ + if (c == '\0') + return S_ISDIR(mode); } else if (c == '\\' && protect_ntfs) { if (is_ntfs_dotgit(path)) return 0; @@ -3088,6 +3095,14 @@ static int do_write_locked_index(struct index_state *istate, struct lock_file *l unsigned flags) { int ret; + int was_full = !istate->sparse_index; + + ret = convert_to_sparse(istate); + + if (ret) { + warning(_("failed to convert to a sparse-index")); + return ret; + } /* * TODO trace2: replace "the_repository" with the actual repo instance @@ -3099,6 +3114,9 @@ static int do_write_locked_index(struct index_state *istate, struct lock_file *l trace2_region_leave_printf("index", "do_write_index", the_repository, "%s", get_lock_file_path(lock)); + if (was_full) + ensure_full_index(istate); + if (ret) return ret; if (flags & COMMIT_LOCK) @@ -3189,9 +3207,10 @@ static int write_shared_index(struct index_state *istate, struct tempfile **temp) { struct split_index *si = istate->split_index; - int ret; + int ret, was_full = !istate->sparse_index; move_cache_to_base_index(istate); + convert_to_sparse(istate); trace2_region_enter_printf("index", "shared/do_write_index", the_repository, "%s", get_tempfile_path(*temp)); @@ -3199,6 +3218,9 @@ static int write_shared_index(struct index_state *istate, trace2_region_leave_printf("index", "shared/do_write_index", the_repository, "%s", get_tempfile_path(*temp)); + if (was_full) + ensure_full_index(istate); + if (ret) return ret; ret = adjust_shared_perm(get_tempfile_path(*temp)); diff --git a/sparse-index.c b/sparse-index.c index 7095378a1b287a..619ff7c2e217ae 100644 --- a/sparse-index.c +++ b/sparse-index.c @@ -4,6 +4,145 @@ #include "tree.h" #include "pathspec.h" #include "trace2.h" +#include "cache-tree.h" +#include "config.h" +#include "dir.h" +#include "fsmonitor.h" + +static struct cache_entry *construct_sparse_dir_entry( + struct index_state *istate, + const char *sparse_dir, + struct cache_tree *tree) +{ + struct cache_entry *de; + + de = make_cache_entry(istate, S_IFDIR, &tree->oid, sparse_dir, 0, 0); + + de->ce_flags |= CE_SKIP_WORKTREE; + return de; +} + +/* + * Returns the number of entries "inserted" into the index. + */ +static int convert_to_sparse_rec(struct index_state *istate, + int num_converted, + int start, int end, + const char *ct_path, size_t ct_pathlen, + struct cache_tree *ct) +{ + int i, can_convert = 1; + int start_converted = num_converted; + enum pattern_match_result match; + int dtype; + struct strbuf child_path = STRBUF_INIT; + struct pattern_list *pl = istate->sparse_checkout_patterns; + + /* + * Is the current path outside of the sparse cone? + * Then check if the region can be replaced by a sparse + * directory entry (everything is sparse and merged). + */ + match = path_matches_pattern_list(ct_path, ct_pathlen, + NULL, &dtype, pl, istate); + if (match != NOT_MATCHED) + can_convert = 0; + + for (i = start; can_convert && i < end; i++) { + struct cache_entry *ce = istate->cache[i]; + + if (ce_stage(ce) || + !(ce->ce_flags & CE_SKIP_WORKTREE)) + can_convert = 0; + } + + if (can_convert) { + struct cache_entry *se; + se = construct_sparse_dir_entry(istate, ct_path, ct); + + istate->cache[num_converted++] = se; + return 1; + } + + for (i = start; i < end; ) { + int count, span, pos = -1; + const char *base, *slash; + struct cache_entry *ce = istate->cache[i]; + + /* + * Detect if this is a normal entry outside of any subtree + * entry. + */ + base = ce->name + ct_pathlen; + slash = strchr(base, '/'); + + if (slash) + pos = cache_tree_subtree_pos(ct, base, slash - base); + + if (pos < 0) { + istate->cache[num_converted++] = ce; + i++; + continue; + } + + strbuf_setlen(&child_path, 0); + strbuf_add(&child_path, ce->name, slash - ce->name + 1); + + span = ct->down[pos]->cache_tree->entry_count; + count = convert_to_sparse_rec(istate, + num_converted, i, i + span, + child_path.buf, child_path.len, + ct->down[pos]->cache_tree); + num_converted += count; + i += span; + } + + strbuf_release(&child_path); + return num_converted - start_converted; +} + +int convert_to_sparse(struct index_state *istate) +{ + if (istate->split_index || istate->sparse_index || + !core_apply_sparse_checkout || !core_sparse_checkout_cone) + return 0; + + /* + * For now, only create a sparse index with the + * GIT_TEST_SPARSE_INDEX environment variable. We will relax + * this once we have a proper way to opt-in (and later still, + * opt-out). + */ + if (!git_env_bool("GIT_TEST_SPARSE_INDEX", 0)) + return 0; + + if (!istate->sparse_checkout_patterns) { + istate->sparse_checkout_patterns = xcalloc(1, sizeof(struct pattern_list)); + if (get_sparse_checkout_patterns(istate->sparse_checkout_patterns) < 0) + return 0; + } + + if (!istate->sparse_checkout_patterns->use_cone_patterns) { + warning(_("attempting to use sparse-index without cone mode")); + return -1; + } + + if (cache_tree_update(istate, 0)) { + warning(_("unable to update cache-tree, staying full")); + return -1; + } + + remove_fsmonitor(istate); + + trace2_region_enter("index", "convert_to_sparse", istate->repo); + istate->cache_nr = convert_to_sparse_rec(istate, + 0, 0, istate->cache_nr, + "", 0, istate->cache_tree); + istate->drop_cache_tree = 1; + istate->sparse_index = 1; + trace2_region_leave("index", "convert_to_sparse", istate->repo); + return 0; +} static void set_index_entry(struct index_state *istate, int nr, struct cache_entry *ce) { diff --git a/sparse-index.h b/sparse-index.h index 09a20d036c4621..64380e121d8035 100644 --- a/sparse-index.h +++ b/sparse-index.h @@ -3,5 +3,6 @@ struct index_state; void ensure_full_index(struct index_state *istate); +int convert_to_sparse(struct index_state *istate); #endif diff --git a/t/t1092-sparse-checkout-compatibility.sh b/t/t1092-sparse-checkout-compatibility.sh index a1aea141c62cc7..1e888d1951226b 100755 --- a/t/t1092-sparse-checkout-compatibility.sh +++ b/t/t1092-sparse-checkout-compatibility.sh @@ -2,6 +2,11 @@ test_description='compare full workdir to sparse workdir' +# The verify_cache_tree() check is not sparse-aware (yet). +# So, disable the check until that integration is complete. +GIT_TEST_CHECK_CACHE_TREE=0 +GIT_TEST_SPLIT_INDEX=0 + . ./test-lib.sh test_expect_success 'setup' ' @@ -121,7 +126,9 @@ run_on_all () { test_all_match () { run_on_all "$@" && test_cmp full-checkout-out sparse-checkout-out && - test_cmp full-checkout-err sparse-checkout-err + test_cmp full-checkout-out sparse-index-out && + test_cmp full-checkout-err sparse-checkout-err && + test_cmp full-checkout-err sparse-index-err } test_sparse_match () { @@ -130,6 +137,38 @@ test_sparse_match () { test_cmp sparse-checkout-err sparse-index-err } +test_expect_success 'sparse-index contents' ' + init_repos && + + test-tool -C sparse-index read-cache --table >cache && + for dir in folder1 folder2 x + do + TREE=$(git -C sparse-index rev-parse HEAD:$dir) && + grep "040000 tree $TREE $dir/" cache \ + || return 1 + done && + + GIT_TEST_SPARSE_INDEX=1 git -C sparse-index sparse-checkout set folder1 && + + test-tool -C sparse-index read-cache --table >cache && + for dir in deep folder2 x + do + TREE=$(git -C sparse-index rev-parse HEAD:$dir) && + grep "040000 tree $TREE $dir/" cache \ + || return 1 + done && + + GIT_TEST_SPARSE_INDEX=1 git -C sparse-index sparse-checkout set deep/deeper1 && + + test-tool -C sparse-index read-cache --table >cache && + for dir in deep/deeper2 folder1 folder2 x + do + TREE=$(git -C sparse-index rev-parse HEAD:$dir) && + grep "040000 tree $TREE $dir/" cache \ + || return 1 + done +' + test_expect_success 'expanded in-memory index matches full index' ' init_repos && test_sparse_match test-tool read-cache --expand --table @@ -137,6 +176,7 @@ test_expect_success 'expanded in-memory index matches full index' ' test_expect_success 'status with options' ' init_repos && + test_sparse_match ls && test_all_match git status --porcelain=v2 && test_all_match git status --porcelain=v2 -z -u && test_all_match git status --porcelain=v2 -uno && @@ -273,6 +313,17 @@ test_expect_failure 'checkout and reset (mixed)' ' test_all_match git reset update-folder2 ' +# Ensure that sparse-index behaves identically to +# sparse-checkout with a full index. +test_expect_success 'checkout and reset (mixed) [sparse]' ' + init_repos && + + test_sparse_match git checkout -b reset-test update-deep && + test_sparse_match git reset deepest && + test_sparse_match git reset update-folder1 && + test_sparse_match git reset update-folder2 +' + test_expect_success 'merge' ' init_repos && @@ -309,14 +360,20 @@ test_expect_success 'clean' ' test_all_match git status --porcelain=v2 && test_all_match git clean -f && test_all_match git status --porcelain=v2 && + test_sparse_match ls && + test_sparse_match ls folder1 && test_all_match git clean -xf && test_all_match git status --porcelain=v2 && + test_sparse_match ls && + test_sparse_match ls folder1 && test_all_match git clean -xdf && test_all_match git status --porcelain=v2 && + test_sparse_match ls && + test_sparse_match ls folder1 && - test_path_is_dir sparse-checkout/folder1 + test_sparse_match test_path_is_dir folder1 ' test_done From bcf0da959ef35f989949b40ae1a386885d116331 Mon Sep 17 00:00:00 2001 From: Derrick Stolee Date: Mon, 11 Jan 2021 10:20:00 -0500 Subject: [PATCH 13/21] submodule: sparse-index should not collapse links A submodule is stored as a "Git link" that actually points to a commit within a submodule. Submodules are populated or not depending on submodule configuration, not sparse-checkout. To ensure that the sparse-index feature integrates correctly with submodules, we should not collapse a directory if there is a Git link within its range. Signed-off-by: Derrick Stolee --- sparse-index.c | 1 + t/t1092-sparse-checkout-compatibility.sh | 17 +++++++++++++++++ 2 files changed, 18 insertions(+) diff --git a/sparse-index.c b/sparse-index.c index 619ff7c2e217ae..7631f7bd00b78e 100644 --- a/sparse-index.c +++ b/sparse-index.c @@ -52,6 +52,7 @@ static int convert_to_sparse_rec(struct index_state *istate, struct cache_entry *ce = istate->cache[i]; if (ce_stage(ce) || + S_ISGITLINK(ce->ce_mode) || !(ce->ce_flags & CE_SKIP_WORKTREE)) can_convert = 0; } diff --git a/t/t1092-sparse-checkout-compatibility.sh b/t/t1092-sparse-checkout-compatibility.sh index 1e888d1951226b..cba5f89b1e96e6 100755 --- a/t/t1092-sparse-checkout-compatibility.sh +++ b/t/t1092-sparse-checkout-compatibility.sh @@ -376,4 +376,21 @@ test_expect_success 'clean' ' test_sparse_match test_path_is_dir folder1 ' +test_expect_success 'submodule handling' ' + init_repos && + + test_all_match mkdir modules && + test_all_match touch modules/a && + test_all_match git add modules && + test_all_match git commit -m "add modules directory" && + + run_on_all git submodule add "$(pwd)/initial-repo" modules/sub && + test_all_match git commit -m "add submodule" && + + # having a submodule prevents "modules" from collapse + test-tool -C sparse-index read-cache --table >cache && + grep "100644 blob .* modules/a" cache && + grep "160000 commit $(git -C initial-repo rev-parse HEAD) modules/sub" cache +' + test_done From 7191b48237dee37c095e7e995913bd37b003dd45 Mon Sep 17 00:00:00 2001 From: Derrick Stolee Date: Tue, 5 Jan 2021 07:51:47 -0500 Subject: [PATCH 14/21] unpack-trees: allow sparse directories The index_pos_by_traverse_info() currently throws a BUG() when a directory entry exists exactly in the index. We need to consider that it is possible to have a directory in a sparse index as long as that entry is itself marked with the skip-worktree bit. The 'pos' variable is assigned a negative value if an exact match is not found. Since a directory name can be an exact match, it is no longer an error to have a nonnegative 'pos' value. Signed-off-by: Derrick Stolee --- unpack-trees.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/unpack-trees.c b/unpack-trees.c index 4dd99219073a4f..0b888dab2246ee 100644 --- a/unpack-trees.c +++ b/unpack-trees.c @@ -746,9 +746,13 @@ static int index_pos_by_traverse_info(struct name_entry *names, strbuf_make_traverse_path(&name, info, names->path, names->pathlen); strbuf_addch(&name, '/'); pos = index_name_pos(o->src_index, name.buf, name.len); - if (pos >= 0) - BUG("This is a directory and should not exist in index"); - pos = -pos - 1; + if (pos >= 0) { + if (!o->src_index->sparse_index || + !(o->src_index->cache[pos]->ce_flags & CE_SKIP_WORKTREE)) + BUG("This is a directory and should not exist in index"); + } else { + pos = -pos - 1; + } if (pos >= o->src_index->cache_nr || !starts_with(o->src_index->cache[pos]->name, name.buf) || (pos > 0 && starts_with(o->src_index->cache[pos-1]->name, name.buf))) From 57be9b4a728b2bb16c841d3bad3c9c876a8839e0 Mon Sep 17 00:00:00 2001 From: Derrick Stolee Date: Fri, 8 Jan 2021 11:05:49 -0500 Subject: [PATCH 15/21] sparse-index: check index conversion happens Add a test case that uses test_region to ensure that we are truly expanding a sparse index to a full one, then converting back to sparse when writing the index. As we integrate more Git commands with the sparse index, we will convert these commands to check that we do _not_ convert the sparse index to a full index and instead stay sparse the entire time. Signed-off-by: Derrick Stolee --- t/t1092-sparse-checkout-compatibility.sh | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/t/t1092-sparse-checkout-compatibility.sh b/t/t1092-sparse-checkout-compatibility.sh index cba5f89b1e96e6..47f98321785204 100755 --- a/t/t1092-sparse-checkout-compatibility.sh +++ b/t/t1092-sparse-checkout-compatibility.sh @@ -393,4 +393,22 @@ test_expect_success 'submodule handling' ' grep "160000 commit $(git -C initial-repo rev-parse HEAD) modules/sub" cache ' +test_expect_success 'sparse-index is expanded and converted back' ' + init_repos && + + ( + GIT_TEST_SPARSE_INDEX=1 && + export GIT_TEST_SPARSE_INDEX && + GIT_TRACE2_EVENT="$(pwd)/trace2.txt" GIT_TRACE2_EVENT_NESTING=10 \ + git -C sparse-index -c core.fsmonitor="" reset --hard && + test_region index convert_to_sparse trace2.txt && + test_region index ensure_full_index trace2.txt && + + rm trace2.txt && + GIT_TRACE2_EVENT="$(pwd)/trace2.txt" GIT_TRACE2_EVENT_NESTING=10 \ + git -C sparse-index -c core.fsmonitor="" status -uno && + test_region index ensure_full_index trace2.txt + ) +' + test_done From c22b4111e49ef810810c54d4afba25db342c24a6 Mon Sep 17 00:00:00 2001 From: Derrick Stolee Date: Mon, 29 Mar 2021 14:29:54 -0400 Subject: [PATCH 16/21] sparse-index: add index.sparse config option When enabled, this config option signals that index writes should attempt to use sparse-directory entries. Signed-off-by: Derrick Stolee --- Documentation/config/index.txt | 5 +++++ cache.h | 1 + repo-settings.c | 7 +++++++ repository.h | 3 ++- sparse-index.c | 34 +++++++++++++++++++++++++++++----- 5 files changed, 44 insertions(+), 6 deletions(-) diff --git a/Documentation/config/index.txt b/Documentation/config/index.txt index 7cb50b37e98dba..75f3a2d1054146 100644 --- a/Documentation/config/index.txt +++ b/Documentation/config/index.txt @@ -14,6 +14,11 @@ index.recordOffsetTable:: Defaults to 'true' if index.threads has been explicitly enabled, 'false' otherwise. +index.sparse:: + When enabled, write the index using sparse-directory entries. This + has no effect unless `core.sparseCheckout` and + `core.sparseCheckoutCone` are both enabled. Defaults to 'false'. + index.threads:: Specifies the number of threads to spawn when loading the index. This is meant to reduce index load time on multiprocessor machines. diff --git a/cache.h b/cache.h index 74b43aaa2bd14f..8aede373aeb34f 100644 --- a/cache.h +++ b/cache.h @@ -1059,6 +1059,7 @@ struct repository_format { int worktree_config; int is_bare; int hash_algo; + int sparse_index; char *work_tree; struct string_list unknown_extensions; struct string_list v1_only_extensions; diff --git a/repo-settings.c b/repo-settings.c index d63569e4041eca..0cfe8b787db26d 100644 --- a/repo-settings.c +++ b/repo-settings.c @@ -85,4 +85,11 @@ void prepare_repo_settings(struct repository *r) * removed. */ r->settings.command_requires_full_index = 1; + + /* + * Initialize this as off. + */ + r->settings.sparse_index = 0; + if (!repo_config_get_bool(r, "index.sparse", &value) && value) + r->settings.sparse_index = 1; } diff --git a/repository.h b/repository.h index e06a2301569722..a45f7520fd9e12 100644 --- a/repository.h +++ b/repository.h @@ -42,7 +42,8 @@ struct repo_settings { int core_multi_pack_index; - unsigned command_requires_full_index:1; + unsigned command_requires_full_index:1, + sparse_index:1; }; struct repository { diff --git a/sparse-index.c b/sparse-index.c index 7631f7bd00b78e..6f4d95d35b1ef9 100644 --- a/sparse-index.c +++ b/sparse-index.c @@ -102,19 +102,43 @@ static int convert_to_sparse_rec(struct index_state *istate, return num_converted - start_converted; } +static int enable_sparse_index(struct repository *repo) +{ + const char *config_path = repo_git_path(repo, "config.worktree"); + + git_config_set_in_file_gently(config_path, + "index.sparse", + "true"); + + prepare_repo_settings(repo); + repo->settings.sparse_index = 1; + return 0; +} + int convert_to_sparse(struct index_state *istate) { if (istate->split_index || istate->sparse_index || !core_apply_sparse_checkout || !core_sparse_checkout_cone) return 0; + if (!istate->repo) + istate->repo = the_repository; + + /* + * The GIT_TEST_SPARSE_INDEX environment variable triggers the + * index.sparse config variable to be on. + */ + if (git_env_bool("GIT_TEST_SPARSE_INDEX", 0)) { + int err = enable_sparse_index(istate->repo); + if (err < 0) + return err; + } + /* - * For now, only create a sparse index with the - * GIT_TEST_SPARSE_INDEX environment variable. We will relax - * this once we have a proper way to opt-in (and later still, - * opt-out). + * Only convert to sparse if index.sparse is set. */ - if (!git_env_bool("GIT_TEST_SPARSE_INDEX", 0)) + prepare_repo_settings(istate->repo); + if (!istate->repo->settings.sparse_index) return 0; if (!istate->sparse_checkout_patterns) { From 75fe9b0f57da2cfc152a0e48f7573d381b4c44d2 Mon Sep 17 00:00:00 2001 From: Derrick Stolee Date: Wed, 13 Jan 2021 08:10:28 -0500 Subject: [PATCH 17/21] sparse-checkout: toggle sparse index from builtin The sparse index extension is used to signal that index writes should be in sparse mode. This was only updated using GIT_TEST_SPARSE_INDEX=1. Add a '--[no-]sparse-index' option to 'git sparse-checkout init' that specifies if the sparse index should be used. It also updates the index to use the correct format, either way. Add a warning in the documentation that the use of a repository extension might reduce compatibility with third-party tools. 'git sparse-checkout init' already sets extension.worktreeConfig, which places most sparse-checkout users outside of the scope of most third-party tools. Update t1092-sparse-checkout-compatibility.sh to use this CLI instead of GIT_TEST_SPARSE_INDEX=1. Signed-off-by: Derrick Stolee --- Documentation/git-sparse-checkout.txt | 14 +++++++ builtin/sparse-checkout.c | 17 ++++++++- sparse-index.c | 33 +++++++++++------ sparse-index.h | 3 ++ t/t1092-sparse-checkout-compatibility.sh | 47 +++++++++++++----------- 5 files changed, 80 insertions(+), 34 deletions(-) diff --git a/Documentation/git-sparse-checkout.txt b/Documentation/git-sparse-checkout.txt index a0eeaeb02ee310..fdcf43f87cb373 100644 --- a/Documentation/git-sparse-checkout.txt +++ b/Documentation/git-sparse-checkout.txt @@ -45,6 +45,20 @@ To avoid interfering with other worktrees, it first enables the When `--cone` is provided, the `core.sparseCheckoutCone` setting is also set, allowing for better performance with a limited set of patterns (see 'CONE PATTERN SET' below). ++ +Use the `--[no-]sparse-index` option to toggle the use of the sparse +index format. This reduces the size of the index to be more closely +aligned with your sparse-checkout definition. This can have significant +performance advantages for commands such as `git status` or `git add`. +This feature is still experimental. Some commands might be slower with +a sparse index until they are properly integrated with the feature. ++ +**WARNING:** Using a sparse index requires modifying the index in a way +that is not completely understood by external tools. If you have trouble +with this compatibility, then run `git sparse-checkout init --no-sparse-index` +to rewrite your index to not be sparse. Older versions of Git will not +understand the sparse directory entries index extension and may fail to +interact with your repository until it is disabled. 'set':: Write a set of patterns to the sparse-checkout file, as given as diff --git a/builtin/sparse-checkout.c b/builtin/sparse-checkout.c index e00b82af727b5d..ca63e2c64e9595 100644 --- a/builtin/sparse-checkout.c +++ b/builtin/sparse-checkout.c @@ -14,6 +14,7 @@ #include "unpack-trees.h" #include "wt-status.h" #include "quote.h" +#include "sparse-index.h" static const char *empty_base = ""; @@ -283,12 +284,13 @@ static int set_config(enum sparse_checkout_mode mode) } static char const * const builtin_sparse_checkout_init_usage[] = { - N_("git sparse-checkout init [--cone]"), + N_("git sparse-checkout init [--cone] [--[no-]sparse-index]"), NULL }; static struct sparse_checkout_init_opts { int cone_mode; + int sparse_index; } init_opts; static int sparse_checkout_init(int argc, const char **argv) @@ -303,11 +305,15 @@ static int sparse_checkout_init(int argc, const char **argv) static struct option builtin_sparse_checkout_init_options[] = { OPT_BOOL(0, "cone", &init_opts.cone_mode, N_("initialize the sparse-checkout in cone mode")), + OPT_BOOL(0, "sparse-index", &init_opts.sparse_index, + N_("toggle the use of a sparse index")), OPT_END(), }; repo_read_index(the_repository); + init_opts.sparse_index = -1; + argc = parse_options(argc, argv, NULL, builtin_sparse_checkout_init_options, builtin_sparse_checkout_init_usage, 0); @@ -326,6 +332,15 @@ static int sparse_checkout_init(int argc, const char **argv) sparse_filename = get_sparse_checkout_filename(); res = add_patterns_from_file_to_list(sparse_filename, "", 0, &pl, NULL); + if (init_opts.sparse_index >= 0) { + if (set_sparse_index_config(the_repository, init_opts.sparse_index) < 0) + die(_("failed to modify sparse-index config")); + + /* force an index rewrite */ + repo_read_index(the_repository); + the_repository->index->updated_workdir = 1; + } + /* If we already have a sparse-checkout file, use it. */ if (res >= 0) { free(sparse_filename); diff --git a/sparse-index.c b/sparse-index.c index 6f4d95d35b1ef9..4c73772c6d6c8f 100644 --- a/sparse-index.c +++ b/sparse-index.c @@ -102,21 +102,32 @@ static int convert_to_sparse_rec(struct index_state *istate, return num_converted - start_converted; } -static int enable_sparse_index(struct repository *repo) +static int set_index_sparse_config(struct repository *repo, int enable) { - const char *config_path = repo_git_path(repo, "config.worktree"); - - git_config_set_in_file_gently(config_path, - "index.sparse", - "true"); + int res; + char *config_path = repo_git_path(repo, "config.worktree"); + res = git_config_set_in_file_gently(config_path, + "index.sparse", + enable ? "true" : NULL); + free(config_path); prepare_repo_settings(repo); repo->settings.sparse_index = 1; - return 0; + return res; +} + +int set_sparse_index_config(struct repository *repo, int enable) +{ + int res = set_index_sparse_config(repo, enable); + + prepare_repo_settings(repo); + repo->settings.sparse_index = enable; + return res; } int convert_to_sparse(struct index_state *istate) { + int test_env; if (istate->split_index || istate->sparse_index || !core_apply_sparse_checkout || !core_sparse_checkout_cone) return 0; @@ -128,11 +139,9 @@ int convert_to_sparse(struct index_state *istate) * The GIT_TEST_SPARSE_INDEX environment variable triggers the * index.sparse config variable to be on. */ - if (git_env_bool("GIT_TEST_SPARSE_INDEX", 0)) { - int err = enable_sparse_index(istate->repo); - if (err < 0) - return err; - } + test_env = git_env_bool("GIT_TEST_SPARSE_INDEX", -1); + if (test_env >= 0) + set_sparse_index_config(istate->repo, test_env); /* * Only convert to sparse if index.sparse is set. diff --git a/sparse-index.h b/sparse-index.h index 64380e121d8035..39dcc859735e2b 100644 --- a/sparse-index.h +++ b/sparse-index.h @@ -5,4 +5,7 @@ struct index_state; void ensure_full_index(struct index_state *istate); int convert_to_sparse(struct index_state *istate); +struct repository; +int set_sparse_index_config(struct repository *repo, int enable); + #endif diff --git a/t/t1092-sparse-checkout-compatibility.sh b/t/t1092-sparse-checkout-compatibility.sh index 47f98321785204..472c5337de1bf4 100755 --- a/t/t1092-sparse-checkout-compatibility.sh +++ b/t/t1092-sparse-checkout-compatibility.sh @@ -6,6 +6,7 @@ test_description='compare full workdir to sparse workdir' # So, disable the check until that integration is complete. GIT_TEST_CHECK_CACHE_TREE=0 GIT_TEST_SPLIT_INDEX=0 +GIT_TEST_SPARSE_INDEX= . ./test-lib.sh @@ -100,25 +101,26 @@ init_repos () { # initialize sparse-checkout definitions git -C sparse-checkout sparse-checkout init --cone && git -C sparse-checkout sparse-checkout set deep && - GIT_TEST_SPARSE_INDEX=1 git -C sparse-index sparse-checkout init --cone && - GIT_TEST_SPARSE_INDEX=1 git -C sparse-index sparse-checkout set deep + git -C sparse-index sparse-checkout init --cone --sparse-index && + test_cmp_config -C sparse-index true index.sparse && + git -C sparse-index sparse-checkout set deep } run_on_sparse () { ( cd sparse-checkout && - GIT_TEST_SPARSE_INDEX=0 "$@" >../sparse-checkout-out 2>../sparse-checkout-err + "$@" >../sparse-checkout-out 2>../sparse-checkout-err ) && ( cd sparse-index && - GIT_TEST_SPARSE_INDEX=1 "$@" >../sparse-index-out 2>../sparse-index-err + "$@" >../sparse-index-out 2>../sparse-index-err ) } run_on_all () { ( cd full-checkout && - GIT_TEST_SPARSE_INDEX=0 "$@" >../full-checkout-out 2>../full-checkout-err + "$@" >../full-checkout-out 2>../full-checkout-err ) && run_on_sparse "$@" } @@ -148,7 +150,7 @@ test_expect_success 'sparse-index contents' ' || return 1 done && - GIT_TEST_SPARSE_INDEX=1 git -C sparse-index sparse-checkout set folder1 && + git -C sparse-index sparse-checkout set folder1 && test-tool -C sparse-index read-cache --table >cache && for dir in deep folder2 x @@ -158,7 +160,7 @@ test_expect_success 'sparse-index contents' ' || return 1 done && - GIT_TEST_SPARSE_INDEX=1 git -C sparse-index sparse-checkout set deep/deeper1 && + git -C sparse-index sparse-checkout set deep/deeper1 && test-tool -C sparse-index read-cache --table >cache && for dir in deep/deeper2 folder1 folder2 x @@ -166,7 +168,14 @@ test_expect_success 'sparse-index contents' ' TREE=$(git -C sparse-index rev-parse HEAD:$dir) && grep "040000 tree $TREE $dir/" cache \ || return 1 - done + done && + + # Disabling the sparse-index removes tree entries with full ones + git -C sparse-index sparse-checkout init --no-sparse-index && + + test-tool -C sparse-index read-cache --table >cache && + ! grep "040000 tree" cache && + test_sparse_match test-tool read-cache --table ' test_expect_success 'expanded in-memory index matches full index' ' @@ -396,19 +405,15 @@ test_expect_success 'submodule handling' ' test_expect_success 'sparse-index is expanded and converted back' ' init_repos && - ( - GIT_TEST_SPARSE_INDEX=1 && - export GIT_TEST_SPARSE_INDEX && - GIT_TRACE2_EVENT="$(pwd)/trace2.txt" GIT_TRACE2_EVENT_NESTING=10 \ - git -C sparse-index -c core.fsmonitor="" reset --hard && - test_region index convert_to_sparse trace2.txt && - test_region index ensure_full_index trace2.txt && - - rm trace2.txt && - GIT_TRACE2_EVENT="$(pwd)/trace2.txt" GIT_TRACE2_EVENT_NESTING=10 \ - git -C sparse-index -c core.fsmonitor="" status -uno && - test_region index ensure_full_index trace2.txt - ) + GIT_TRACE2_EVENT="$(pwd)/trace2.txt" GIT_TRACE2_EVENT_NESTING=10 \ + git -C sparse-index -c core.fsmonitor="" reset --hard && + test_region index convert_to_sparse trace2.txt && + test_region index ensure_full_index trace2.txt && + + rm trace2.txt && + GIT_TRACE2_EVENT="$(pwd)/trace2.txt" GIT_TRACE2_EVENT_NESTING=10 \ + git -C sparse-index -c core.fsmonitor="" status -uno && + test_region index ensure_full_index trace2.txt ' test_done From 7f55a232e6479b62efc7b97d04cdf3ad11a0623d Mon Sep 17 00:00:00 2001 From: Derrick Stolee Date: Thu, 18 Feb 2021 11:37:45 -0500 Subject: [PATCH 18/21] sparse-checkout: disable sparse-index We use 'git sparse-checkout init --cone --sparse-index' to toggle the sparse-index feature. It makes sense to also disable it when running 'git sparse-checkout disable'. This is particularly important because it removes the extensions.sparseIndex config option, allowing other tools to use this Git repository again. This does mean that 'git sparse-checkout init' will not re-enable the sparse-index feature, even if it was previously enabled. While testing this feature, I noticed that the sparse-index was not being written on the first run, but by a second. This was caught by the call to 'test-tool read-cache --table'. This requires adjusting some assignments to core_apply_sparse_checkout and pl.use_cone_patterns in the sparse_checkout_init() logic. Signed-off-by: Derrick Stolee --- builtin/sparse-checkout.c | 10 +++++++++- t/t1091-sparse-checkout-builtin.sh | 13 +++++++++++++ 2 files changed, 22 insertions(+), 1 deletion(-) diff --git a/builtin/sparse-checkout.c b/builtin/sparse-checkout.c index ca63e2c64e9595..585343fa1972ca 100644 --- a/builtin/sparse-checkout.c +++ b/builtin/sparse-checkout.c @@ -280,6 +280,9 @@ static int set_config(enum sparse_checkout_mode mode) "core.sparseCheckoutCone", mode == MODE_CONE_PATTERNS ? "true" : NULL); + if (mode == MODE_NO_PATTERNS) + set_sparse_index_config(the_repository, 0); + return 0; } @@ -341,10 +344,11 @@ static int sparse_checkout_init(int argc, const char **argv) the_repository->index->updated_workdir = 1; } + core_apply_sparse_checkout = 1; + /* If we already have a sparse-checkout file, use it. */ if (res >= 0) { free(sparse_filename); - core_apply_sparse_checkout = 1; return update_working_directory(NULL); } @@ -366,6 +370,7 @@ static int sparse_checkout_init(int argc, const char **argv) add_pattern(strbuf_detach(&pattern, NULL), empty_base, 0, &pl, 0); strbuf_addstr(&pattern, "!/*/"); add_pattern(strbuf_detach(&pattern, NULL), empty_base, 0, &pl, 0); + pl.use_cone_patterns = init_opts.cone_mode; return write_patterns_and_update(&pl); } @@ -632,6 +637,9 @@ static int sparse_checkout_disable(int argc, const char **argv) strbuf_addstr(&match_all, "/*"); add_pattern(strbuf_detach(&match_all, NULL), empty_base, 0, &pl, 0); + prepare_repo_settings(the_repository); + the_repository->settings.sparse_index = 0; + if (update_working_directory(&pl)) die(_("error while refreshing working directory")); diff --git a/t/t1091-sparse-checkout-builtin.sh b/t/t1091-sparse-checkout-builtin.sh index fc64e9ed99f4bf..38fc8340f5c9b7 100755 --- a/t/t1091-sparse-checkout-builtin.sh +++ b/t/t1091-sparse-checkout-builtin.sh @@ -205,6 +205,19 @@ test_expect_success 'sparse-checkout disable' ' check_files repo a deep folder1 folder2 ' +test_expect_success 'sparse-index enabled and disabled' ' + git -C repo sparse-checkout init --cone --sparse-index && + test_cmp_config -C repo true index.sparse && + test-tool -C repo read-cache --table >cache && + grep " tree " cache && + + git -C repo sparse-checkout disable && + test-tool -C repo read-cache --table >cache && + ! grep " tree " cache && + git -C repo config --list >config && + ! grep index.sparse config +' + test_expect_success 'cone mode: init and set' ' git -C repo sparse-checkout init --cone && git -C repo config --list >config && From 365901809d9d43f1229ac3e81990853b06b8fb35 Mon Sep 17 00:00:00 2001 From: Derrick Stolee Date: Wed, 13 Jan 2021 06:59:46 -0500 Subject: [PATCH 19/21] cache-tree: integrate with sparse directory entries The cache-tree extension was previously disabled with sparse indexes. However, the cache-tree is an important performance feature for commands like 'git status' and 'git add'. Integrate it with sparse directory entries. When writing a sparse index, completely clear and recalculate the cache tree. By starting from scratch, the only integration necessary is to check if we hit a sparse directory entry and create a leaf of the cache-tree that has an entry_count of one and no subtrees. Signed-off-by: Derrick Stolee --- cache-tree.c | 18 ++++++++++++++++++ sparse-index.c | 10 +++++++++- 2 files changed, 27 insertions(+), 1 deletion(-) diff --git a/cache-tree.c b/cache-tree.c index 5f07a39e501e63..950a9615db8fcd 100644 --- a/cache-tree.c +++ b/cache-tree.c @@ -256,6 +256,24 @@ static int update_one(struct cache_tree *it, *skip_count = 0; + /* + * If the first entry of this region is a sparse directory + * entry corresponding exactly to 'base', then this cache_tree + * struct is a "leaf" in the data structure, pointing to the + * tree OID specified in the entry. + */ + if (entries > 0) { + const struct cache_entry *ce = cache[0]; + + if (S_ISSPARSEDIR(ce->ce_mode) && + ce->ce_namelen == baselen && + !strncmp(ce->name, base, baselen)) { + it->entry_count = 1; + oidcpy(&it->oid, &ce->oid); + return 1; + } + } + if (0 <= it->entry_count && has_object_file(&it->oid)) return it->entry_count; diff --git a/sparse-index.c b/sparse-index.c index 4c73772c6d6c8f..95ea17174da3b8 100644 --- a/sparse-index.c +++ b/sparse-index.c @@ -172,7 +172,11 @@ int convert_to_sparse(struct index_state *istate) istate->cache_nr = convert_to_sparse_rec(istate, 0, 0, istate->cache_nr, "", 0, istate->cache_tree); - istate->drop_cache_tree = 1; + + /* Clear and recompute the cache-tree */ + cache_tree_free(&istate->cache_tree); + cache_tree_update(istate, 0); + istate->sparse_index = 1; trace2_region_leave("index", "convert_to_sparse", istate->repo); return 0; @@ -273,5 +277,9 @@ void ensure_full_index(struct index_state *istate) strbuf_release(&base); free(full); + /* Clear and recompute the cache-tree */ + cache_tree_free(&istate->cache_tree); + cache_tree_update(istate, 0); + trace2_region_leave("index", "ensure_full_index", istate->repo); } From 9b068c458898edfc5267c06e37563f66fac148cf Mon Sep 17 00:00:00 2001 From: Derrick Stolee Date: Tue, 16 Feb 2021 14:45:16 -0500 Subject: [PATCH 20/21] sparse-index: loose integration with cache_tree_verify() The cache_tree_verify() method is run when GIT_TEST_CHECK_CACHE_TREE is enabled, which it is by default in the test suite. The logic must be adjusted for the presence of these directory entries. For now, leave the test as a simple check for whether the directory entry is sparse. Do not go any further until needed. This allows us to re-enable GIT_TEST_CHECK_CACHE_TREE in t1092-sparse-checkout-compatibility.sh. Further, p2000-sparse-operations.sh uses the test suite and hence this is enabled for all tests. We need to integrate with it before we run our performance tests with a sparse-index. Signed-off-by: Derrick Stolee --- cache-tree.c | 19 +++++++++++++++++++ t/t1092-sparse-checkout-compatibility.sh | 3 --- 2 files changed, 19 insertions(+), 3 deletions(-) diff --git a/cache-tree.c b/cache-tree.c index 950a9615db8fcd..11bf1fcae6e1d6 100644 --- a/cache-tree.c +++ b/cache-tree.c @@ -808,6 +808,19 @@ int cache_tree_matches_traversal(struct cache_tree *root, return 0; } +static void verify_one_sparse(struct repository *r, + struct index_state *istate, + struct cache_tree *it, + struct strbuf *path, + int pos) +{ + struct cache_entry *ce = istate->cache[pos]; + + if (!S_ISSPARSEDIR(ce->ce_mode)) + BUG("directory '%s' is present in index, but not sparse", + path->buf); +} + static void verify_one(struct repository *r, struct index_state *istate, struct cache_tree *it, @@ -830,6 +843,12 @@ static void verify_one(struct repository *r, if (path->len) { pos = index_name_pos(istate, path->buf, path->len); + + if (pos >= 0) { + verify_one_sparse(r, istate, it, path, pos); + return; + } + pos = -pos - 1; } else { pos = 0; diff --git a/t/t1092-sparse-checkout-compatibility.sh b/t/t1092-sparse-checkout-compatibility.sh index 472c5337de1bf4..12e6c453024fdf 100755 --- a/t/t1092-sparse-checkout-compatibility.sh +++ b/t/t1092-sparse-checkout-compatibility.sh @@ -2,9 +2,6 @@ test_description='compare full workdir to sparse workdir' -# The verify_cache_tree() check is not sparse-aware (yet). -# So, disable the check until that integration is complete. -GIT_TEST_CHECK_CACHE_TREE=0 GIT_TEST_SPLIT_INDEX=0 GIT_TEST_SPARSE_INDEX= From 66602733cc95d9a53594520cd8b28d3338e258ea Mon Sep 17 00:00:00 2001 From: Derrick Stolee Date: Mon, 15 Feb 2021 14:39:27 -0500 Subject: [PATCH 21/21] p2000: add sparse-index repos p2000-sparse-operations.sh compares different Git commands in repositories with many files at HEAD but using sparse-checkout to focus on a small portion of those files. Add extra copies of the repository that use the sparse-index format so we can track how that affects the performance of different commands. At this point in time, the sparse-index is 100% overhead from the CPU front, and this is measurable in these tests: Test --------------------------------------------------------------- 2000.2: git status (full-index-v3) 0.59(0.51+0.12) 2000.3: git status (full-index-v4) 0.59(0.52+0.11) 2000.4: git status (sparse-index-v3) 1.40(1.32+0.12) 2000.5: git status (sparse-index-v4) 1.41(1.36+0.08) 2000.6: git add -A (full-index-v3) 2.32(1.97+0.19) 2000.7: git add -A (full-index-v4) 2.17(1.92+0.14) 2000.8: git add -A (sparse-index-v3) 2.31(2.21+0.15) 2000.9: git add -A (sparse-index-v4) 2.30(2.20+0.13) 2000.10: git add . (full-index-v3) 2.39(2.02+0.20) 2000.11: git add . (full-index-v4) 2.20(1.94+0.16) 2000.12: git add . (sparse-index-v3) 2.36(2.27+0.12) 2000.13: git add . (sparse-index-v4) 2.33(2.21+0.16) 2000.14: git commit -a -m A (full-index-v3) 2.47(2.12+0.20) 2000.15: git commit -a -m A (full-index-v4) 2.26(2.00+0.17) 2000.16: git commit -a -m A (sparse-index-v3) 3.01(2.92+0.16) 2000.17: git commit -a -m A (sparse-index-v4) 3.01(2.94+0.15) Note that there is very little difference between the v3 and v4 index formats when the sparse-index is enabled. This is primarily due to the fact that the relative file sizes are the same, and the command time is mostly taken up by parsing tree objects to expand the sparse index into a full one. With the current file layout, the index file sizes are given by this table: | full index | sparse index | +-------------+--------------+ v3 | 108 MiB | 1.6 MiB | v4 | 80 MiB | 1.2 MiB | Future updates will improve the performance of Git commands when the index is sparse. Signed-off-by: Derrick Stolee --- t/perf/p2000-sparse-operations.sh | 19 ++++++++++++++++++- 1 file changed, 18 insertions(+), 1 deletion(-) diff --git a/t/perf/p2000-sparse-operations.sh b/t/perf/p2000-sparse-operations.sh index dddd527b633034..94513c97748943 100755 --- a/t/perf/p2000-sparse-operations.sh +++ b/t/perf/p2000-sparse-operations.sh @@ -59,12 +59,29 @@ test_expect_success 'setup repo and indexes' ' git sparse-checkout set $SPARSE_CONE && git config index.version 4 && git update-index --index-version=4 + ) && + git -c core.sparseCheckoutCone=true clone --branch=wide --sparse . sparse-index-v3 && + ( + cd sparse-index-v3 && + git sparse-checkout init --cone --sparse-index && + git sparse-checkout set $SPARSE_CONE && + git config index.version 3 && + git update-index --index-version=3 + ) && + git -c core.sparseCheckoutCone=true clone --branch=wide --sparse . sparse-index-v4 && + ( + cd sparse-index-v4 && + git sparse-checkout init --cone --sparse-index && + git sparse-checkout set $SPARSE_CONE && + git config index.version 4 && + git update-index --index-version=4 ) ' test_perf_on_all () { command="$@" - for repo in full-index-v3 full-index-v4 + for repo in full-index-v3 full-index-v4 \ + sparse-index-v3 sparse-index-v4 do test_perf "$command ($repo)" " (