fix: Dynamic code cancellation no longer leaves Unity busy

[hatayama]

Summary

• Dynamic code execution now releases cancellation promptly even when the executed code returns an async task that ignores cancellation.
• Late task failures remain observed, and completed task results or failures are preserved when cancellation arrives at the same time.

User Impact

• Before this change, canceling a dynamic-code operation could leave Unity or the CLI communication path appearing stuck until the editor was restarted.
• After this change, cancellation returns a clean canceled result and the next dynamic-code request can run normally.

Changes

• Make dynamic-code awaiting cancellation-aware while keeping await continuations context-free.
• Observe late faults from abandoned user tasks so they do not surface as unrelated unobserved exceptions.
• Add EditMode coverage for cancellation release, late-fault observation, completed result preservation, and completed fault preservation.

Verification

• cli/dist/darwin-arm64/uloop compile --project-path "$(git rev-parse --show-toplevel)"
• cli/dist/darwin-arm64/uloop run-tests --project-path "$(git rev-parse --show-toplevel)" --test-mode EditMode --filter-type regex --filter-value "io\\.github\\.hatayama\\.UnityCliLoop\\.Tests\\.Editor\\.DynamicCodeToolTests\\.CommandRunnerCancellationTests\\..*"
• cli/dist/darwin-arm64/uloop run-tests --project-path "$(git rev-parse --show-toplevel)" --test-mode EditMode --filter-type regex --filter-value "io\\.github\\.hatayama\\.UnityCliLoop\\.Tests\\.Editor\\.DynamicCodeToolTests\\..*"
• ~/.codex/skills/codex-review/scripts/codex-review --parallel-tests ... v3-beta returned clean with no accepted/actionable findings.

[coderabbitai]

Caution

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ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

Run ID: 623a28b6-e23f-4f9c-8b7a-12e0241f4427

📥 Commits

Reviewing files that changed from the base of the PR and between ada8255 and d78132d.

⛔ Files ignored due to path filters (1)

• Assets/Tests/Editor/DynamicCodeToolTests/CommandRunnerCancellationTests.cs.meta is excluded by none and included by none

📒 Files selected for processing (3)

• Assets/Tests/Editor/DynamicCodeToolTests/CommandRunnerCancellationTests.cs
• Packages/src/Editor/FirstPartyTools/ExecuteDynamicCode/Execution/AwaitableHelper.cs
• Packages/src/Editor/FirstPartyTools/ExecuteDynamicCode/Execution/CommandRunner.cs

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📝 Walkthrough

Walkthrough

AwaitableHelper.AwaitIfNeeded gains a CancellationToken parameter and three new private helpers (AwaitTaskWithCancellationAsync, ObserveAbandonedTaskFaultAsync, AwaitObjectTaskWithCancellationAsync) that implement Task.WhenAny-based cancellation with fault observation for abandoned tasks. CommandRunner.ExecuteInternalAsync now forwards its token to AwaitIfNeeded. A new test fixture validates cancellation scenarios.

Changes

Cancellation-aware async execution

Layer / File(s)	Summary
AwaitIfNeeded signature, cancellation helpers, and CommandRunner wiring Packages/src/Editor/FirstPartyTools/ExecuteDynamicCode/Execution/AwaitableHelper.cs, Packages/src/Editor/FirstPartyTools/ExecuteDynamicCode/Execution/CommandRunner.cs	AwaitIfNeeded adds a CancellationToken parameter and routes Task/ValueTask awaiting through new AwaitTaskWithCancellationAsync helper (uses Task.WhenAny + a cancellation TaskCompletionSource). ObserveAbandonedTaskFaultAsync attaches a fault-observing continuation to tasks abandoned by cancellation. The awaitable-pattern fallback path is updated to use AwaitObjectTaskWithCancellationAsync. CommandRunner.ExecuteInternalAsync passes cancellationToken to AwaitIfNeeded.
Cancellation test fixture, state coordinator, and DynamicCommand wrapper Assets/Tests/Editor/DynamicCodeToolTests/CommandRunnerCancellationTests.cs	CommandRunnerCancellationTests adds four tests covering: runner recovery after async code ignores cancellation, fault observation on an abandoned task, and AwaitIfNeeded behavior when the token is already canceled at task completion. WrappedDynamicCommandState uses TaskCompletionSource signals to script started/blocking/returning behaviors. UnityCliLoop.Dynamic.DynamicCommand wraps WrappedDynamicCommandState.ExecuteAsync.

Sequence Diagram(s)

sequenceDiagram
  participant CommandRunner
  participant AwaitIfNeeded
  participant AwaitTaskWithCancellationAsync
  participant ObserveAbandonedTaskFaultAsync

  CommandRunner->>AwaitIfNeeded: AwaitIfNeeded(invoked, cancellationToken)
  AwaitIfNeeded->>AwaitTaskWithCancellationAsync: forward task + cancellationToken

  rect rgba(255, 100, 100, 0.5)
    Note over AwaitTaskWithCancellationAsync: cancellation fires first
    AwaitTaskWithCancellationAsync->>ObserveAbandonedTaskFaultAsync: attach fault-observer continuation
    AwaitTaskWithCancellationAsync-->>AwaitIfNeeded: throw OperationCanceledException
    AwaitIfNeeded-->>CommandRunner: propagate cancellation
  end

  rect rgba(100, 200, 100, 0.5)
    Note over AwaitTaskWithCancellationAsync: task completes first
    AwaitTaskWithCancellationAsync-->>AwaitIfNeeded: return Task<object> result
    AwaitIfNeeded-->>CommandRunner: return result
  end

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Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~25 minutes

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 15.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title 'fix: Dynamic code cancellation no longer leaves Unity busy' directly addresses the main issue fixed in this PR—cancellation now releases resources promptly instead of leaving the system stuck.
Description check	✅ Passed	The description comprehensively explains the fix, user impact, implementation approach, and verification steps, all directly related to the changeset's goal of fixing cancellation behavior in dynamic code execution.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch feature/hatayama/fix-frame-debugger-hang

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[cubic-dev-ai]

No issues found across 4 files

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