more

pkg/outbox/outbox.go

@@ -23,6 +23,7 @@ import (
 	"errors"
 	"log/slog"
 	"os"
+	"path/filepath"
 	"sort"
 	"sync"
 	"time"
@@ -144,6 +145,12 @@ func (o *Outbox) compact() error {
 	if err := os.Rename(tmp, o.path); err != nil {
 		return err
 	}
+	// fsync the directory so the rename (the file swap) is itself durable — a
+	// crash right after must not leave the pending log lost or a stale .tmp.
+	if d, derr := os.Open(filepath.Dir(o.path)); derr == nil {
+		_ = d.Sync()
+		_ = d.Close()
+	}
 	o.f, err = os.OpenFile(o.path, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0o644)
 	return err
 }