[cyanzhong]

Skip unnecessary reverts when file-change notifications report content identical to the current document.

[Copilot]

🟡 Changes recommended

A race with pending file reads can install stale content after acknowledging disk changes, while skipped raw-data cache refreshes can make Reopen with Encoding restore older text.

2 open issues

• Prevent pending reads from overwriting a newer disk state · New
• Refresh cached file data when acknowledging matching content · New

What changed in this PR

This PR avoids unnecessary editor reloads when external file-change notifications report bytes identical to the current document, while preserving reloads for changed content and text bundles.

Changes:

• Add coordinated content comparison and modification-date tracking to the shared document helper.
• Run external-change handling on the main queue.
• Add tests for matching content, subsequent saves, changed bytes, unsynchronized text, and text bundles.

File	Description
MarkEditMac/​Tests/​EditorDocumentTests.swift	Verify external text-bundle edits still reload and preserve assets.
MarkEditMac/​Tests/​EditorDocumentSaveTests.swift	Cover skipped reverts, save behavior, and required reloads.
MarkEditMac/​Sources/​Editor/​Models/​EditorDocument.swift	Delegate external-change handling to the helper on the main queue.
MarkEditMac/​Modules/​Sources/​AppKitExtensions/​Foundation/​NSDocument+Extension.swift	Add coordinated timestamp and content checks before reverting.

_{Review effort: Balanced}

[Copilot]

🟡 Changes recommended

Synchronous file coordination on the main queue can deadlock with a writer waiting for autosave, so the disk read must move off-main with state revalidation before applying the result.

1 open issue

• Avoid blocking the main queue during coordinated reads · New

2 resolved since last review

• Prevent pending reads from overwriting a newer disk state
• Refresh cached file data when acknowledging matching content

_{Review effort: Balanced}

[Copilot]

🟡 Changes recommended

An external write matching unsaved edits leaves the editor’s saved undo checkpoint stale, so undoing can incorrectly mark the document clean and allow changes to be discarded on close without prompting.

1 open issue

• Update saved undo checkpoint when external content matches edits · New

1 resolved since last review

• Avoid blocking the main queue during coordinated reads

_{Review effort: Balanced}

[Copilot]

🟡 Changes recommended

Regression tests are missing for the new skip-revert path and pending-read retry, leaving identical-content handling, changed-content reloads, and pending-decode behavior unprotected.

1 open issue

• Add regression tests for skip-revert and pending-read retry · New

1 resolved since last review

• Update saved undo checkpoint when external content matches edits

_{Review effort: Balanced}