Enforce maximum length in entity instance ids

[halspang]

Summary

What changed?

• Enforce maximum length of entity instances

Why is this change needed?

• The backend expects a maximum length of 100 characters for an Entity's ID. This change enforces that at the SDK level, allowing for an opt-in breaking change to eliminate bad behavior on the backend.

Issues / work items

• Resolves #
• Related #

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Project checklist

• Release notes are not required for the next release
  • Otherwise: Notes added to release_notes.md
• Backport is not required
  • Otherwise: Backport tracked by issue/PR #issue_or_pr
• All required tests have been added/updated (unit tests, E2E tests)
• Breaking change?
  • Impact: Users will no longer be able to specify Entity Instance Ids (combination of name and key) longer than 100 characters
  • Migration guidance: Use smaller name/key combos for Entities. If entities already exist with IDs that are too long, you must use the truncated value to access them: entityInstanceId.ToString().Take(100)

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AI-assisted code disclosure (required)

Was an AI tool used? (select one)

• No
• Yes, AI helped write parts of this PR (e.g., GitHub Copilot)
• Yes, an AI agent generated most of this PR

If AI was used:

• Tool(s):
• AI-assisted areas/files:
• What you changed after AI output:

AI verification (required if AI was used):

• I understand the code and can explain it
• I verified referenced APIs/types exist and are correct
• I reviewed edge cases/failure paths (timeouts, retries, cancellation, exceptions)
• I reviewed concurrency/async behavior
• I checked for unintended breaking or behavior changes

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Testing

Automated tests

• Result: Passed

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Notes for reviewers

• N/A

[Copilot]

Pull request overview

This PR enforces a maximum serialized length (100 chars) for EntityInstanceId values in the Abstractions layer, aligning SDK behavior with the backend’s entity instance ID constraints and preventing backend-side truncation/invalid IDs.

Changes:

• Added a length check in EntityInstanceId construction to reject instance IDs whose string form exceeds 100 characters.
• Added new unit tests covering basic EntityInstanceId behaviors and invalid inputs.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.

File	Description
src/Abstractions/Entities/EntityInstanceId.cs	Enforces a 100-character maximum entity instance ID length during construction (also impacts FromString/JSON conversion).
test/Abstractions.Tests/Entities/EntityInstanceIdTests.cs	Adds unit tests for constructor behavior, normalization, parsing, and invalid formats/lengths.

[Copilot]

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.

[Copilot]

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

[Copilot]

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated no new comments.

Comments suppressed due to low confidence (3)

test/Abstractions.Tests/Entities/EntityInstanceIdTests.cs:11

• Test method names in this project typically follow the "MemberOrScenario_Condition_Expectation" style (e.g., Ctor_NullName_Default, FromString_Invalid_Throws...). Using the generic "Test..." prefix here is inconsistent and makes failures harder to scan in test output.

    public void TestValidEntityInstanceId()

src/Abstractions/Entities/EntityInstanceId.cs:37

• The length validation uses MaxInstanceIdLength but the exception message hard-codes "100". This can drift if the limit is changed later and makes the constant less useful; interpolate the constant into the message.

            throw new ArgumentException($"entity instance ids may not exceed 100 characters in length, actual length {length}.");

test/Abstractions.Tests/Entities/EntityInstanceIdTests.cs:6

• Namespace is inconsistent with the other entity tests in this project (e.g., other files under test/Abstractions.Tests/Entities use Microsoft.DurableTask.Entities.Tests). Aligning the namespace improves discoverability and keeps related tests grouped consistently.

This issue also appears on line 11 of the same file.

namespace Microsoft.DurableTask.Abstractions.Tests.Entities;