[dborgards]

Superseded by #450, opened concurrently for the same issue 16 seconds before this PR. Both implement the same ownership seam and unsubscribe-after-dispose fix; #450 retains the active review and CI. Closing this duplicate to keep one authored PR open.

What does this change?

IsoTpChannel.Dispose now keeps its background-exception handler attached until its owned actor has finished disposing. A callback that outlives the actor's shutdown timeout therefore reaches channel subscribers through the existing asynchronous dispatcher. Borrowed actors remain owned by their callers and the channel still detaches its handler.

Closes #449. No public API change; the internal test constructor can explicitly take ownership of an injected actor.

Type of change

• feat — new behaviour (minor release)
• fix / perf — bug or performance fix (patch release)
• docs / test / refactor / chore / ci — no release
• Breaking change

Checklist

• Build with -p:CI=true, test (net10.0), dotnet format --verify-no-changes, and pack + eng/verify-packages.py all pass locally
• Public API changes are documented with XML comments — no public API change
• New behaviour is covered by a test
• The requirement or ADR this relates to is referenced — FR-RAW-023

Validation

• Release build: zero warnings and errors; full net10.0 suite: 2881/2881 passed.
• Regression: IsoTpChannelIntegrationTests.The_Shutdown_Timeout_Of_The_Channels_Own_Actor_Reaches_Its_Subscribers holds the actor callback until finally and awaits the dispatched timeout report. Restoring the old unsubscribe-before-dispose ordering makes this test fail with a timeout; restoring the fix passes.
• Local Cobertura: the modified Dispose ownership branch has 100% condition coverage (2/2), and all modified executable lines have hits. All class entries for the source file were inspected, including nested types.
• Format verification passed; fresh pack verified all 9 packages. Requirements traceability reports no new gaps; all 50 verification-script tests pass.
• net48 execution is left to Windows CI.

[cursor]

PR Summary

Medium Risk
Changes dispose ordering and actor-ownership semantics on the ISO-TP channel teardown path; behavior is covered by a new integration test and leaves the public API unchanged.

Overview
Fixes #449 / FR-RAW-023: when IsoTpChannel owns its ProtocolActor, Dispose now calls _actor.Dispose() before unsubscribing from BackgroundExceptionOccurred, so a shutdown join timeout raised during actor disposal still reaches channel subscribers via the existing async dispatcher. Borrowed actors are unchanged—the handler is always removed; only owned actors are disposed by the channel.

The internal test constructor gains an optional ownsActor flag so tests can inject an actor but still have the channel dispose it (production still creates and owns the actor when none is passed).

Adds The_Shutdown_Timeout_Of_The_Channels_Own_Actor_Reaches_Its_Subscribers, which blocks an actor callback across Dispose and asserts a TimeoutException is observed on BackgroundExceptionOccurred.

^{Reviewed by Cursor Bugbot for commit 1053891. Bugbot is set up for automated code reviews on this repo. Configure here.}

[chatgpt-codex-connector]

Codex Review Summary

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Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-10-25T09:53:43.357619Z	1053891	PR opened

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✅ All modified and coverable lines are covered by tests.

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