Bug: breadcrumb-dispatch-message-and-handoff-record-inaccurate

[drmoisan]

• Work Mode: minor-audit

Summary

The breadcrumb test dispatcher's exception message, and one earlier handoff record, describe the DispatchValue path inaccurately. These are wording and documentation defects only; behavior is correct.

Environment

• OS/version: n/a
• Python version: n/a (C#)
• Command/flags used: n/a
• Data source or fixture: n/a

Steps to Reproduce

1. Read QuickFiler/Viewers/BreadcrumbUiDispatcher.cs lines ~101 and ~183, and the assertion at QuickFiler.Test/Viewers/BreadcrumbUiThreadDispatchTests.cs:305.
2. Compare the message with what the owner-thread-only DispatchValue path actually does.
3. Read the earlier breadcrumb thread-affinity follow-up handoff record, which attributes one DispatchValue site to the owner-thread-id check.

Expected Behavior

The message and the asserted wording describe the specific DispatchValue behavior, and the handoff record attributes each site to the check that actually governs it.

Actual Behavior

• The message "The owner-thread-only test dispatcher cannot marshal cross-thread UI work." is broader than the DispatchValue mechanism, and the test asserts the broad wording with *cannot marshal cross-thread UI work*.
• The earlier handoff record misattributes one DispatchValue site to the owner-thread-id check.

Logs / Screenshots

• Attached minimal logs or screenshot
• Snippet: see the PR test(931): remove scheduler and file-handle dependence from breadcrumb thread-affinity and FileInfoWrapper tests #939 body, section Follow-ups, items 3 and 4.

Impact / Severity

• Blocker
• High
• Medium
• Low

Source

From: docs/features/potential/2026-09-29-breadcrumb-dispatch-message-and-handoff-record-inaccurate.md

[drmoisan]

Restoring sections dropped by the promotion tooling.

Suspected Cause / Notes

Both defects originate from the breadcrumb thread-affinity work, and both were found by the #931 review (PR #939, Follow-ups items 3 and 4).

Source: docs/features/active/2026-09-28-tests-depend-on-uncontrolled-environment-931/evidence/qa-gates/p4-t13-follow-up-handoff.2026-09-29T09-46.md.

Proposed Fix / Validation Ideas

• Narrow the message text at QuickFiler/Viewers/BreadcrumbUiDispatcher.cs (lines ~101 and ~183), and update the WithMessage pattern at QuickFiler.Test/Viewers/BreadcrumbUiThreadDispatchTests.cs:305 to match.
• Correct the handoff record's attribution of the DispatchValue site.