Make Cmd+Shift+T reopen the last closed item

[austinywang]

Summary

• move the built-in Cmd+Shift+T binding from the workspace-only action to the existing unified Reopen Last Closed action
• restore the newest closed panel, workspace, or whole window through the shared ClosedItemHistoryStore LIFO path, including window workspaces and geometry
• preserve explicit legacy workspace-only bindings while keeping the existing action ID compatible with cmux.json and Settings
• document the new default and localize the shared shortcut label in English and Japanese

Architecture

This builds on the existing close-history owner rather than adding window-only state. Window closure already records a value-typed SessionWindowSnapshot, and restoration creates a fresh AppKit window from that snapshot. No live closed-window or PTY context is retained, and surface-level restore can continue to share the same stack (#4427).

Validation

• regression test committed before the fix; focused red proof: https://github.com/manaflow-ai/cmux/actions/runs/30427465225
• swift test --disable-xctest --package-path Packages/macOS/CmuxSettings (265 tests passed)
• ./scripts/lint-pbxproj-test-wiring.sh (626 test files)
• Swift frontend parse of all touched Swift/test files
• localization catalog parse plus English/Japanese key verification
• dependency-free TypeScript bundle check for web/data/cmux-shortcuts.ts
• git diff --check

Closes #9126
Cross-reference: #4427

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Summary by cubic

Cmd+Shift+T now reopens the last closed item—panel, workspace, or window—in LIFO order and restores window geometry. Settings now also preserve legacy unbindings so Cmd+Shift+T won’t override them. Closes #9126.

• New Features

  • Bind “Reopen Last Closed” to Cmd+Shift+T (panels/workspaces/windows; restores window frames).
  • Localized label (EN/JA); command palette and docs/web shortcuts updated; keeps the reopenClosedBrowserPanel action ID for Settings compatibility.

• Migration

  • reopenClosedWorkspace is unbound by default; Cmd+Shift+T defaults to reopenClosedBrowserPanel.
  • Existing explicit bindings or unbindings for reopenClosedWorkspace are preserved and suppress the default on reopenClosedBrowserPanel.

^{Written for commit bdf5cc9. Summary will update on new commits.}

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: ASSERTIVE

Plan: Pro Plus

Run ID: e7033bb9-8470-4f0c-8b2d-587257fc5173

📥 Commits

Reviewing files that changed from the base of the PR and between dec474e and bdf5cc9.

📒 Files selected for processing (13)

• Packages/macOS/CmuxSettings/Sources/CmuxSettings/Values/ShortcutAction+Defaults.swift
• Packages/macOS/CmuxSettings/Sources/CmuxSettings/Values/ShortcutAction+DisplayName.swift
• Packages/macOS/CmuxSettings/Sources/CmuxSettings/Values/ShortcutAction+LegacyDefaultResolution.swift
• Packages/macOS/CmuxSettingsUI/Sources/CmuxSettingsUI/Bindings/ShortcutListModel+Resolution.swift
• Packages/macOS/CmuxSettingsUI/Tests/CmuxSettingsUITests/ShortcutListLegacyOverrideTests.swift
• Sources/KeyboardShortcutSettings.swift
• Sources/KeyboardShortcutSettingsLookup.swift
• cmux.xcodeproj/project.pbxproj
• cmuxTests/KeyboardShortcutContextSwiftTests.swift
• cmuxTests/ReopenLastClosedTests.swift
• cmuxTests/WorkspaceRecoveryTests.swift
• skills/cmux-settings/references/shortcut-actions.md
• web/data/cmux-shortcuts.ts

💤 Files with no reviewable changes (1)

• cmuxTests/WorkspaceRecoveryTests.swift

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📝 Walkthrough

Walkthrough

Cmd+Shift+T now defaults to reopening closed browser panels while legacy workspace bindings can displace that default. Shortcut resolution, UI binding lookup, documentation, and window-restoration tests were updated accordingly.

Changes

Reopen Last Closed Shortcut

Layer / File(s)	Summary
Shortcut defaults and conflict resolution Packages/macOS/CmuxSettings/..., Sources/KeyboardShortcutSettings*, skills/cmux-settings/..., web/data/cmux-shortcuts.ts	The browser-panel action receives Cmd+Shift+T, the workspace action becomes unbound by default, and legacy conflict resolution handles explicit workspace bindings.
UI binding lookup and overrides Packages/macOS/CmuxSettingsUI/Bindings/..., Packages/macOS/CmuxSettingsUI/Tests/...	Explicit shortcut lookup is centralized, with tests covering workspace overrides and unbindings.
Window restoration and shortcut tests cmuxTests/ReopenLastClosedTests.swift, cmuxTests/KeyboardShortcutContextSwiftTests.swift, cmuxTests/WorkspaceRecoveryTests.swift, cmux.xcodeproj/project.pbxproj	Tests cover mixed history restoration, window LIFO reopening, shortcut metadata, conflict resolution, and project inclusion of the new test suite.

Estimated code review effort: 4 (Complex) | ~45 minutes

Sequence Diagram(s)

sequenceDiagram
  participant User
  participant KeyboardShortcutSettings
  participant ClosedItemHistoryStore
  participant MainWindow
  User->>KeyboardShortcutSettings: Press Cmd+Shift+T
  KeyboardShortcutSettings->>ClosedItemHistoryStore: Restore newest closed item
  ClosedItemHistoryStore->>MainWindow: Reopen window or panel
  MainWindow-->>User: Restore workspace, tabs, and frame

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Possibly related issues

• Issue 6999: Covers the same ReopenLastClosedTests and Cmd+Shift+T shortcut migration.
• Issue 7000: Covers the same restoration tests and shortcut default changes.

Possibly related PRs

• manaflow-ai/cmux#8841: Updates the same reopen-last-closed shortcut pair and legacy conflict-resolution behavior.

Suggested reviewers: lawrencecchen, azooz2003-bit

🚥 Pre-merge checks | ✅ 24 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (24 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title is concise and accurately highlights the main change: Cmd+Shift+T now reopens the last closed item.
Description check	✅ Passed	The description covers the change, rationale, validation, and issue linkage, though some template sections are only lightly filled.
Linked Issues check	✅ Passed	The changes satisfy #9126 by making Cmd+Shift+T reopen the latest closed item in LIFO order, including windows, with customizable bindings.
Out of Scope Changes check	✅ Passed	The added tests, docs, project wiring, and localization all support the shortcut and restore behavior, with no clear unrelated scope.
Cmux Swift Actor Isolation	✅ Passed	No new actor-isolation debt: the new production helpers are pure/value-side, and the only @MainActor additions are tests; ShortcutListModel stays MainActor-isolated.
Cmux Swift Blocking Runtime	✅ Passed	Touched production Swift files add no semaphores, sleeps, locks, syncs, or polling; the only waitUntil loop is confined to the new test suite.
Cmux Browser Automation Off-Main	✅ Passed	PR only changes shortcut/settings and tests; it does not touch the scoped browser automation files or routing policy.
Cmux Expensive Synchronous Load	✅ Passed	Touched files only adjust shortcut conflict resolution and tests; no agent-history loaders, broad scans, or heavy sync parsing were added to main/interactive paths.
Cmux Cache Substitution Correctness	✅ Passed	PASS: The new shortcut lookups use event-driven stores with initial snapshots; UI starts observing before use, so no stale/cold cache substitution in a persistence path.
Cmux No Hacky Sleeps	✅ Passed	No changed non-Swift runtime code uses sleeps/timers; the touched TS file is static shortcut data, and the only polling helper is Swift test-only.
Cmux Algorithmic Complexity	✅ Passed	All new logic is O(1) dictionary/set lookup or fixed enum mapping; no nested scans, batch rescans, or hot-path re-sorting were added.
Cmux Swift Concurrency	✅ Passed	No new legacy async patterns appear in the touched cmux Swift code; the only Task usage is test-only Task.yield(), which the rule allows.
Cmux Swift @Concurrent	✅ Passed	No touched Swift code adds or changes async isolation/@Concurrent; the new test work is explicitly @MainActor UI-bound.
Cmux Swift Package Boundaries	✅ Passed	PASS: The only production Swift change is in CmuxSettings package code; app-root Sources/ are untouched, and the new legacy-resolution logic is package-scoped and testable.
Cmux Swiftpm Lockfiles	✅ Passed	pbxproj only adds ReopenLastClosedTests wiring; no Package.resolved, Package.swift, or .gitignore changes, and no SwiftPM package-reference edits were present.
Cmux Swift Logging	✅ Passed	No added print/debugPrint/dump/NSLog/Logger in touched production Swift; the only stdout use is in XCTest assertions, which the policy allows.
Cmux User-Facing Error Privacy	✅ Passed	PASS: Touched production files only change shortcut defaults/labels/conflict resolution; no user-facing errors, alerts, API bodies, or sensitive details were added.
Cmux Full Internationalization	✅ Passed	Swift uses String(localized:) with existing xcstrings entries; web routing/messages are locale-aligned, and the only web copy change is a moved EN/JA note, not new untranslated text.
Cmux Swiftui State Layout	✅ Passed	Touched SwiftUI-adjacent code only refactors shortcut resolution; no new ObservableObject/@published, GeometryReader, lazy-row store refs, or render-time state writes were introduced.
Cmux Architecture Rethink	✅ Passed	PASS: The diff adds synchronous legacy-default resolution and localization; the only polling/synchronization is confined to tests, with no new runtime timing/observer/lock side channels.
Cmux Swift Auxiliary Window Close Shortcuts	✅ Passed	Diff only changes shortcut/settings code and test-only window fixtures; no new standalone cmux-owned window, identifier, or close-shortcut ownership changes.
Cmux Source Artifacts	✅ Passed	All changed paths are intentional source/docs/tests/config/data; none are logs, caches, scratch dirs, or build artifacts.
Cmux No Test Or Debug Seam In Production Source	✅ Passed	The only production-source patch adds legacy conflict-resolution logic in ShortcutAction+LegacyDefaultResolution.swift; no #if DEBUG seam or test-only accessor was added.
Cmux No Ambient Global State	✅ Passed	Touched production Swift adds/adjusts extension methods and private helpers only; no new file-scope funcs, mutable globals, or singleton/state ownership patterns were introduced.

✨ Finishing Touches 💡 1

📝 Generate docstrings 💡

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch issue-9126-cmdshiftt-reopen-window

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