yellowjacket/.planning/phases/02-backend-correctness/02-01-PLAN.md

---
phase: 02-backend-correctness
plan: 01
type: execute
wave: 1
depends_on: []
files_modified:
  - backend/app.go
  - backend/config/config.go
autonomous: true
requirements: [CORR-05, CORR-06, CORR-07]

must_haves:
  truths:
    - "Package-level startupErr variable no longer exists; startup errors are stored in a YellowJacketApp struct field"
    - "Config files are written with 0o644 permissions"
    - "MPRIS callback errors (Pause, Seek) appear in the application log instead of being silently discarded"
  artifacts:
    - path: "backend/app.go"
      provides: "Startup error as struct field + MPRIS error logging"
      contains: "startupErr error"
    - path: "backend/config/config.go"
      provides: "Secure config file permissions"
      contains: "0o644"
  key_links:
    - from: "backend/app.go:OnStartup"
      to: "backend/app.go:OnDomReady"
      via: "yj.startupErr field (not package-level var)"
      pattern: "yj\\.startupErr"
    - from: "backend/app.go:MPRIS callbacks"
      to: "yj.logger"
      via: "Warn log on Pause/Seek error"
      pattern: "yj\\.logger\\.Warn.*MPRIS"
---

<objective>
Fix three independent error handling gaps in the application shell and config layer: eliminate the package-level startupErr variable, secure config file permissions, and log MPRIS callback errors.

Purpose: Remove global mutable state (startupErr), prevent world-writable config files, and ensure MPRIS failures are observable in logs.
Output: Modified `backend/app.go` and `backend/config/config.go` with all three fixes applied.
</objective>

<execution_context>
@/home/caleb/.config/opencode/get-shit-done/workflows/execute-plan.md
@/home/caleb/.config/opencode/get-shit-done/templates/summary.md
</execution_context>

<context>
@.planning/ROADMAP.md
@.planning/STATE.md
@.planning/phases/02-backend-correctness/02-CONTEXT.md
@.planning/phases/02-backend-correctness/02-RESEARCH.md

@backend/app.go
@backend/config/config.go

<interfaces>
<!-- Key types and contracts the executor needs. Extracted from codebase. -->

From backend/app.go:
```go
// YellowJacketApp is the main application struct for Wails.
type YellowJacketApp struct {
    FEBindings   []any
    FrontendUtil *frontendutil.FrontendUtil

    logger        *slog.Logger
    assetHandler  *assets.Handler
    database      *database.DB
    library       *library.Library
    player        *player.Player
    playlist      *playlist.Service
    queue         *queue.Queue
    mediaControls mediacontrols.Handler
    appContext    context.Context
    appConfig     *config.Config
}

var startupErr error  // line 134 — TO BE REMOVED

func (yj *YellowJacketApp) OnStartup(ctx context.Context)  // line 137 — uses startupErr
func (yj *YellowJacketApp) OnDomReady(ctx context.Context)  // line 251 — checks startupErr
```

MPRIS callback closures at lines 181-203:
```go
OnPause: func() { _ = yj.player.Pause() },
OnPlayPause: func() {
    if yj.player.IsPlaying() {
        _ = yj.player.Pause()
    } else {
        yj.queue.Play()
    }
},
OnStop:     func() { _ = yj.player.Pause() },
OnSeek: func(positionSec int) {
    _ = yj.player.Seek(positionSec)
},
```
</interfaces>
</context>

<tasks>

<task type="auto">
  <name>Task 1: Move startupErr to struct field and fix config permissions</name>
  <files>backend/app.go, backend/config/config.go</files>
  <action>
**CORR-05 — Startup error struct field (backend/app.go):**
1. Add `startupErr error` field to the `YellowJacketApp` struct (after `appConfig`)
2. Delete the package-level `var startupErr error` declaration at line 134
3. In `OnStartup` (line 154-155): change `startupErr = errors.Join(startupErr, ...)` to `yj.startupErr = errors.Join(yj.startupErr, ...)`
4. In `OnDomReady` (line 252-254): change `if startupErr != nil` to `if yj.startupErr != nil`, and `startupErr.Error()` to `yj.startupErr.Error()`
5. Verify no other references to the package-level `startupErr` exist

**CORR-06 — Config permissions (backend/config/config.go):**
1. At line 152, change `os.FileMode(int(0o666))` to `0o644`
2. This is a single expression replacement — the `os.WriteFile` call signature stays the same
  </action>
  <verify>
    <automated>cd /mnt/vault/dev/golang/yellowjacket && go vet ./backend/... && grep -q "startupErr error" backend/app.go && ! grep -q "^var startupErr" backend/app.go && grep -q "0o644" backend/config/config.go && ! grep -q "0o666" backend/config/config.go</automated>
  </verify>
  <done>Package-level startupErr is gone; YellowJacketApp has startupErr field; OnStartup and OnDomReady reference yj.startupErr; config.go writes with 0o644 permissions</done>
</task>

<task type="auto">
  <name>Task 2: Log MPRIS callback errors</name>
  <files>backend/app.go</files>
  <action>
**CORR-07 — MPRIS callback error logging (backend/app.go):**

Replace the four MPRIS closures (lines 183-195) that discard errors with closures that log on failure. Use `Warn` level per research recommendation — these are non-fatal conditions. Keep inline closures (no named method extraction).

1. **OnPause** (line 183): Replace `func() { _ = yj.player.Pause() }` with:
```go
func() {
    if err := yj.player.Pause(); err != nil {
        yj.logger.Warn("MPRIS Pause failed", "err", err)
    }
}
```

2. **OnPlayPause** (lines 184-189): Replace the `_ = yj.player.Pause()` inside the `if yj.player.IsPlaying()` branch:
```go
func() {
    if yj.player.IsPlaying() {
        if err := yj.player.Pause(); err != nil {
            yj.logger.Warn("MPRIS PlayPause(pause) failed", "err", err)
        }
    } else {
        yj.queue.Play()
    }
}
```

3. **OnStop** (line 191): Replace `func() { _ = yj.player.Pause() }` with:
```go
func() {
    if err := yj.player.Pause(); err != nil {
        yj.logger.Warn("MPRIS Stop failed", "err", err)
    }
}
```

4. **OnSeek** (lines 194-196): Replace `func(positionSec int) { _ = yj.player.Seek(positionSec) }` with:
```go
func(positionSec int) {
    if err := yj.player.Seek(positionSec); err != nil {
        yj.logger.Warn("MPRIS Seek failed", "err", err)
    }
}
```

Ensure all four closures no longer use `_ =` to discard errors.
  </action>
  <verify>
    <automated>cd /mnt/vault/dev/golang/yellowjacket && go vet ./backend/... && ! grep -q '_ = yj.player.Pause()' backend/app.go && ! grep -q '_ = yj.player.Seek' backend/app.go && grep -c 'MPRIS.*failed' backend/app.go | grep -q '^4$'</automated>
  </verify>
  <done>All four MPRIS callbacks (OnPause, OnPlayPause, OnStop, OnSeek) check errors and log at Warn level; no discarded errors remain in MPRIS closures</done>
</task>

</tasks>

<verification>
```bash
# All backend packages compile and pass vet
go vet ./backend/...

# No package-level startupErr
! grep -q "^var startupErr" backend/app.go

# Struct field exists
grep -q "startupErr error" backend/app.go

# Config permissions fixed
grep -q "0o644" backend/config/config.go
! grep -q "0o666" backend/config/config.go

# MPRIS errors logged (4 occurrences)
test "$(grep -c 'MPRIS.*failed' backend/app.go)" -eq 4

# No discarded player errors in MPRIS closures
! grep -q '_ = yj.player' backend/app.go

# Linting passes
golangci-lint run ./backend/...
```
</verification>

<success_criteria>
- `go vet ./backend/...` passes
- `golangci-lint run ./backend/...` passes
- Package-level `startupErr` variable eliminated
- Config file written with 0o644 permissions
- All four MPRIS callbacks log errors at Warn level
</success_criteria>

<output>
After completion, create `.planning/phases/02-backend-correctness/02-01-SUMMARY.md`
</output>