Fix stale diff views not refreshing on file or tree changes

[Jinwoo-H]

Summary

Fixes #4730 — diff tabs stayed stale after file or git changes, and re-clicking a node in the source-control or combined-diff tree did not refresh the view.

• Bump diffContentReloadNonce when re-opening an existing single-file diff tab (openDiff / openBranchDiff / openCommitDiff) so cached bodies refetch
• Reload unstaged/staged single-file diff tabs when the active file's git status entry changes (not the whole worktree)
• Include staged diff tabs in external file-watch reload routing and overflow recovery
• Combined diff: retry loaded/in-flight sections on tree re-navigation and external file changes, skipping dirty inline edits
• Bust in-flight diff read dedup on forced reloads to avoid stale promise results

Review fixes (auto-review-fix)

• Scoped git-status reload to the active file's status signature; skip duplicate fetch on initial tab open
• Guard combined-diff reloads against dirty sections and in-flight loads
• Stabilized combined-diff external-change listener deps via ref

Validation

• pnpm vitest run — editor-panel-diff-reload, editor-autosave, editor, useEditorExternalWatch tests (149 passing)
• pnpm run typecheck:web
• Electron E2E: unstaged diff auto-reloads on external edit; re-click reloads without closing tab

Made with Orca 🐋

[pullfrog]

Important

One moderate correctness issue: retrySection in CombinedDiffViewer should bump generation to prevent stale in-flight fetches from flashing old content.

Reviewed changes — fixes stale diff views by adding a diffContentReloadNonce signal for re-opening existing diff tabs, scoping git-status reloads to the active file's entries, and extending the combined diff viewer to reload sections on tree navigation and external file changes.

• Add diffContentReloadNonce to OpenFile — bumped on re-opening existing diff tabs via openDiff, openBranchDiff, and openCommitDiff; the panel effect clears cached content and force-reloads when the nonce changes.
• Extract isReloadableSingleFileDiffTab and shouldReloadDiffOnGitStatusChange — replace inline diffSource checks across the panel, external events, and lazy-load effects.
• Scope git-status reload to the active file — compute activeFileGitStatusSignature from only the matching status entries, eliminating spurious reloads when unrelated files change.
• Include staged diff tabs in external file-watch routing — isExternalReloadableEditorTab and getOpenFilesForExternalFileChange now match staged diffs, and getOverflowExternalReloadTargets routes them to overflow recovery.
• Combined diff: reload on tree navigation and external changes — requestCombinedDiffSectionReload retries loaded/in-flight sections with dirty-edit guards; an external-change listener reloads matching uncommitted sections.

---

Note: 1 inline comment(s) dropped because they did not anchor to lines inside the PR diff:

• src/renderer/src/components/editor/CombinedDiffViewer.tsx:627-648 (RIGHT) — start_line 627 (RIGHT) is not inside a diff hunk

  ^{｜ Fix it ➔ ｜ View workflow run ｜ Using DeepSeek Pro (free via Pullfrog for OSS) ｜ 𝕏}

[pullfrog]

✅ No new issues found. All prior review feedback addressed.

Reviewed changes — the new commit a00dc4a rotates Monaco diff model keys via content-signature-based identities, hardens combined-diff reload with git-status signature tracking, and adds E2E verification scripts.

• Rotate Monaco diff model keys via content signatures — EditorContent.tsx keys DiffViewer with the content hash + reload nonce to force a fresh mount when fetched blobs change; ChangesModeView.tsx uses the shared getDiffContentSignature for the original-side model key rotation.
• Bump contentGeneration in retrySection — addresses the prior review's generation concern. The combined-diff load scheduler's rerequest clears in-flight queue slots before re-enqueuing, and DiffSectionItem.tsx incorporates contentGeneration into its Monaco model path key.
• Add git-status signature tracking to combined diff — buildCombinedGitStatusSignature scopes cache restores to matching sections; an effect reloads all loaded sections when git status entries for those files change.
• Add module-level external-change listener for unmounted combined-diff tabs — invalidates the view state cache so remounts don't replay stale section bodies.
• Extract shared predicates and utilities — isReloadableSingleFileDiffTab, shouldReloadDiffOnGitStatusChange, isExternalReloadableEditorTab, and getDiffContentSignature replace inline checks across the editor panel, external events, and file watch subsystems.
• Add three E2E verification scripts — Playwright CDP scripts (diff-reload-e2e-verify.mjs, diff-reload-ssh-e2e-verify.mjs, diff-reload-ssh-local-e2e-verify.mjs) cover local, SSH Docker container, and SSH localhost diff-reload scenarios.
• Bust in-flight diff dedup on forced reloads — loadDiffContent now accepts { force?: boolean }; external-change events pass force: true to avoid stale promise results.

  ^{｜ View workflow run ｜ Using DeepSeek Pro (free via Pullfrog for OSS) ｜ 𝕏}