Inject FocusLogStore instead of a shared singleton

[azooz2003-bit]

Follow-up to the CmuxUpdater extraction (#5132), which de-singletoned UpdateLogStore. FocusLogStore (the DEBUG-only focus-event diagnostic logger that lives in the same file) still self-vended a static let shared.

This applies the same fix: AppDelegate owns the single FocusLogStore instance next to updateLog, so its lifecycle has one composition root. The in-AppDelegate call sites use the instance directly; the GhosttyTerminalView and Workspace sites reach it via AppDelegate.shared?.focusLog, mirroring the existing AppDelegate.shared?.updateLog precedent. The type is now a plain injectable class with a documented @unchecked Sendable (its mutable state stays confined to the serial queue, unchanged).

The second commit compile-time guards the FOCUSDBG NSLog in GhosttyNSView.focusLog behind #if DEBUG (it was runtime-gated only), per the repo debug-log requirement.

No production behavior change. FocusLogStore.append is already #if DEBUG; this only moves ownership.

Testing

• ./scripts/reload.sh --tag focuslog-di builds green.
• Verified no test target references the removed FocusLogStore.shared symbol.
• CI tests-build-and-lag and the CoreAnimation main-thread startup regression pass on the build.
• No new behavior to exercise at runtime: focus logging (~/Library/Logs/cmux-focus.log, the Copy Focus Logs menu action) works exactly as before, now sourced from the AppDelegate-owned instance.

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Project	Deployment	Actions	Updated (UTC)
cmux	Ready	Preview, Comment	Jun 2, 2026 8:34pm
cmux-staging	Building	Preview, Comment	Jun 2, 2026 8:34pm

[coderabbitai]

📝 Walkthrough

Walkthrough

FocusLogStore is converted from a singleton to an externally-constructible instance; AppDelegate now owns a FocusLogStore instance and all DEBUG focus-log writes (AppDelegate internals, Workspace, GhosttyTerminalView) are redirected to AppDelegate.shared?.focusLog. Clipboard export uses the instance snapshot/logPath.

Changes

Focus Logging Injection Refactoring

Layer / File(s)	Summary
FocusLogStore instance-based API Sources/Update/UpdateLogStore.swift	Removes static let shared singleton and private init(), exposes public init(), and adds @unchecked Sendable conformance to enable external lifecycle composition.
AppDelegate focusLog ownership and adoption Sources/AppDelegate.swift	Adds focusLog instance property; updates internal DEBUG logging call sites to use focusLog.append(...) and changes copyFocusLogs to use focusLog.snapshot() / focusLog.logPath().
Logging call-site updates in terminal and workspace Sources/GhosttyTerminalView.swift, Sources/Workspace.swift	Redirects DEBUG focus logging from FocusLogStore.shared.append() to AppDelegate.shared?.focusLog.append() using optional chaining at workspace and terminal call sites.

Sequence Diagram

sequenceDiagram
    participant AppDelegate
    participant FocusLogStore
    participant Workspace
    participant GhosttyNSView

    AppDelegate->>FocusLogStore: init() on app startup
    Workspace->>AppDelegate: AppDelegate.shared?.focusLog.append(message)
    AppDelegate->>FocusLogStore: append(message)
    GhosttyNSView->>AppDelegate: AppDelegate.shared?.focusLog.append(message)
    AppDelegate->>FocusLogStore: append(message)
    AppDelegate->>FocusLogStore: snapshot() + logPath() for clipboard

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Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Poem

I was once a global, shouting logs at will—
Now AppDelegate tends me, steady and still.
Messages hop through optional doors,
Snapped to clipboard and saved in drawers.
A rabbit cheers composition, soft and trill 🐇✨

🚥 Pre-merge checks | ✅ 17 | ❌ 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 (17 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title 'Inject FocusLogStore instead of a shared singleton' accurately and concisely summarizes the main architectural change in the pull request—replacing a singleton pattern with dependency injection.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Cmux Swift Actor Isolation	✅ Passed	FocusLogStore marked @unchecked Sendable with serial queue isolation; AppDelegate @MainActor owns instance; all call sites appropriately access from MainActor/MainThread contexts.
Cmux Swift Blocking Runtime	✅ Passed	PR refactors FocusLogStore from singleton to instance injection without introducing blocking operations. Existing queue.sync is only called from UI menu action.
Cmux No Hacky Sleeps	✅ Passed	Check out of scope: PR changes only Swift files, but this check covers TypeScript, JavaScript, shell, and non-Swift build/runtime scripts only.
Cmux Algorithmic Complexity	✅ Passed	All focusLog.append() calls are single debug-log events, most #if DEBUG guarded, never in loops. FocusLogStore uses bounded 400-entry buffer; no algorithmic complexity violations detected.
Cmux Swift Concurrency	✅ Passed	PR refactors FocusLogStore from singleton to injectable pattern; pre-existing serial DispatchQueue usage is retained unchanged, no new legacy async patterns introduced.
Cmux Swift @Concurrent	✅ Passed	PR converts FocusLogStore from singleton to injectable; introduces no async functions, @concurrent annotations, or concurrency violations.
Cmux Swift File And Package Boundaries	✅ Passed	Refactoring adds minimal lines to existing oversized files (7, 3, 5, 2 lines) all below 250-line threshold. No new responsibilities, no mixed concerns; appropriate app-target glue code.
Cmux Swift Logging	✅ Passed	NSLog in GhosttyTerminalView is properly guarded by #if DEBUG; all focusLog calls are debug-only (#if DEBUG blocks) with no secrets exposed; file logging follows established UpdateLogStore pattern.
Cmux User-Facing Error Privacy	✅ Passed	Focus log messages are developer-only debug info guarded by #if DEBUG, stored locally in ~/Library/Logs/, not user-facing. No sensitive information exposed.
Cmux Full Internationalization	✅ Passed	PR contains debug-only focus logging refactoring with #if DEBUG guards; no new user-facing text or unlocalized strings added.
Cmux Swiftui State Layout	✅ Passed	PR introduces no new SwiftUI observable state. FocusLogStore is a plain logging utility with @unchecked Sendable. Usage in AppKit views and existing ObservableObjects are incidental and approved.
Cmux Architecture Rethink	✅ Passed	Converts FocusLogStore from singleton to AppDelegate-injected instance. No prohibited patterns (sleeps, locks, observers, channels). Uses safe optional chaining with proper serial queue thread safety.
Cmux Swift Auxiliary Window Close Shortcuts	✅ Passed	PR refactors FocusLogStore (logging utility) from singleton to injectable—no NSWindow, NSPanel, NSWindowController, Window, or WindowGroup additions.
Description check	✅ Passed	The pull request description provides a clear summary of changes, testing approach, and the rationale for the dependency injection pattern. All required template sections are addressed.

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✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch feat-focuslogstore-di

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[azooz2003-bit]

@codex review

[chatgpt-codex-connector]

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[greptile-apps]

Greptile Summary

This PR de-singletones FocusLogStore to match the existing UpdateLogStore DI pattern: AppDelegate now owns a single focusLog instance, and all call sites in GhosttyTerminalView and Workspace are updated to reach it via AppDelegate.shared?.focusLog. The refactor is clean and consistent with the established pattern.

• UpdateLogStore.swift: Removes static let shared, opens init(), and adds an @unchecked Sendable conformance with a clear queue-confinement comment.
• AppDelegate.swift: Adds let focusLog = FocusLogStore() as a stored property; all in-file call sites use it directly.
• GhosttyTerminalView.swift: Switches to AppDelegate.shared?.focusLog; also wraps the previously bare NSLog(\"[FOCUSDBG]\") in #if DEBUG, which is a correct tightening of production logging.

Confidence Score: 5/5

Safe to merge; this is a clean DI refactor with no behavioral change in debug builds and a negligible side effect in release builds.

All changed code is mechanical: singleton removed, stored property added to AppDelegate, call sites updated. The only noteworthy difference is that FocusLogStore.init() — and therefore ensureLogFile() — now runs unconditionally in release builds, creating an empty log file that was previously never created. This is cosmetic and has no functional impact on users.

Sources/Update/UpdateLogStore.swift — FocusLogStore.init() calls ensureLogFile() unconditionally, creating an empty log file in release builds that did not exist before.

Important Files Changed

Filename	Overview
Sources/Update/UpdateLogStore.swift	Removes static let shared from FocusLogStore, makes init() public, and adds @unchecked Sendable conformance with a clear documentation comment explaining the queue-confinement invariant.
Sources/AppDelegate.swift	Adds let focusLog = FocusLogStore() as a stored property next to updateLog. All in-file call sites updated. Because stored properties initialise unconditionally, FocusLogStore.init() (including ensureLogFile()) now always runs in release builds, which was not the case before this PR.
Sources/GhosttyTerminalView.swift	Updates focusLog() to use AppDelegate.shared?.focusLog; also wraps the pre-existing bare NSLog inside #if DEBUG, which is an improvement per the logging rule.
Sources/Workspace.swift	Two call sites inside #if DEBUG blocks updated from FocusLogStore.shared to AppDelegate.shared?.focusLog; mechanical change with no behavior difference.

Sequence Diagram

sequenceDiagram
    participant AD as AppDelegate
    participant FLS as FocusLogStore
    participant GTV as GhosttyNSView
    participant WS as Workspace

    Note over AD: App startup
    AD->>FLS: "init() → let focusLog = FocusLogStore()"

    Note over GTV: focusDebugEnabled check
    GTV->>AD: AppDelegate.shared?.focusLog
    AD-->>GTV: FocusLogStore instance
    GTV->>FLS: "append(message) [#if DEBUG only]"

    Note over WS: Inside #if DEBUG block
    WS->>AD: AppDelegate.shared?.focusLog
    AD-->>WS: FocusLogStore instance
    WS->>FLS: append(message)

    Note over AD: copyFocusLogs action
    AD->>FLS: snapshot() / logPath()
    FLS-->>AD: entries / path

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_{Reviews (2): Last reviewed commit: "Compile-time guard the FOCUSDBG NSLog in..." | Re-trigger Greptile}

[cubic-dev-ai]

No issues found across 4 files

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