Unify panic recovery into service.RecoverWorker

cmd/player/main.go had recoverBackgroundWorkerPanic and
internal/service/recover.go had handleWorkerPanic implementing the same
log-and-stack panic recovery. Export the service variant as RecoverWorker
(unchanged signature), use it from main.go, and drop the duplicate
helper plus the now-unused runtime/debug import.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

5 files changed, 25 insertions, 12 deletions

diff --git a/player-server/cmd/player/main.go b/player-server/cmd/player/main.go
index 72bff60..8835a1a 100644
--- a/player-server/cmd/player/main.go
+++ b/player-server/cmd/player/main.go
@@ -8,7 +8,6 @@ import (
 	"net/http"
 	"os"
 	"os/signal"
-	"runtime/debug"
 	"syscall"
 	"time"
 
@@ -82,12 +81,6 @@ func buildLogger(logLevel string) *slog.Logger {
 	return slog.New(slog.NewTextHandler(os.Stderr, &slog.HandlerOptions{Level: level}))
 }
 
-func recoverBackgroundWorkerPanic(logger *slog.Logger, worker string) {
-	if r := recover(); r != nil && logger != nil {
-		logger.Error("background worker panic", "worker", worker, "panic", r, "stack", string(debug.Stack()))
-	}
-}
-
 // wireDeps constructs the core service layer dependencies.
 func wireDeps(cfg *internal.Config, store repository.Store, logger *slog.Logger, appCtx context.Context) *appDeps {
 	clk := clock.RealClock{}
@@ -144,7 +137,12 @@ func startBackgroundWorkers(deps *appDeps) {
 			select {
 			case <-ticker.C:
 				func() {
-					defer recoverBackgroundWorkerPanic(deps.logger, "podcast checker")
+					// Use the unified service.RecoverWorker helper so this
+					// matches every other background-worker panic path in
+					// the codebase (gc, rescan, podcast feed check).
+					defer func() {
+						service.RecoverWorker(deps.logger, "podcast checker", recover())
+					}()
 					if err := deps.podcastSvc.CheckFeeds(context.Background()); err != nil {
 						deps.logger.Error("podcast feed check failed", "err", err)
 					}
diff --git a/player-server/internal/service/gc.go b/player-server/internal/service/gc.go
index 6eb485a..ab7f646 100644
--- a/player-server/internal/service/gc.go
+++ b/player-server/internal/service/gc.go
@@ -72,7 +72,7 @@ func (w *GCWorker) Start() {
 			case <-tickCh:
 				func() {
 					defer func() {
-						handleWorkerPanic(w.logger, "gc", recover())
+						RecoverWorker(w.logger, "gc", recover())
 					}()
 					w.run(w.ctx)
 				}()
diff --git a/player-server/internal/service/podcast_checker.go b/player-server/internal/service/podcast_checker.go
index 1de920c..362fd0e 100644
--- a/player-server/internal/service/podcast_checker.go
+++ b/player-server/internal/service/podcast_checker.go
@@ -42,7 +42,7 @@ func (s *podcastFeedChecker) CheckFeeds(ctx context.Context) error {
 		go func(f model.PodcastFeed) {
 			defer wg.Done()
 			defer func() {
-				handleWorkerPanic(s.logger, "podcast feed check", recover())
+				RecoverWorker(s.logger, "podcast feed check", recover())
 			}()
 			if err := s.checkFeed(ctx, f); err != nil {
 				s.logger.Warn("podcast feed check failed", "feed_id", f.ID, "feed_url", f.FeedURL, "err", err)
diff --git a/player-server/internal/service/recover.go b/player-server/internal/service/recover.go
index c89a78e..59a4716 100644
--- a/player-server/internal/service/recover.go
+++ b/player-server/internal/service/recover.go
@@ -6,7 +6,22 @@ import (
 	"runtime/debug"
 )
 
-func handleWorkerPanic(logger *slog.Logger, worker string, r any) error {
+// RecoverWorker is the unified panic-recovery helper for background workers.
+// Pass the value returned by recover() in r; when non-nil it logs the panic
+// together with the stack trace and returns a formatted error so callers can
+// propagate the failure (e.g. to scan progress) if they care. When r is nil
+// the function is a no-op, which makes it safe to use unconditionally inside
+// a deferred wrapper.
+//
+// Typical usage:
+//
+//	defer func() {
+//	    service.RecoverWorker(logger, "podcast checker", recover())
+//	}()
+//
+// This consolidates what used to be duplicated as handleWorkerPanic (here)
+// and recoverBackgroundWorkerPanic (in cmd/player) into one exported variant.
+func RecoverWorker(logger *slog.Logger, worker string, r any) error {
 	if r == nil {
 		return nil
 	}
diff --git a/player-server/internal/service/scan.go b/player-server/internal/service/scan.go
index da5c54f..fe9513b 100644
--- a/player-server/internal/service/scan.go
+++ b/player-server/internal/service/scan.go
@@ -61,7 +61,7 @@ func (s *scanService) TriggerRescan(ctx context.Context) error {
 		defer cancel()
 		defer s.notifyDone()
 		defer func() {
-			if err := handleWorkerPanic(s.logger, "rescan", recover()); err != nil {
+			if err := RecoverWorker(s.logger, "rescan", recover()); err != nil {
 				progress.Done(err)
 			}
 		}()