fix: reap zombie child processes in container environments

cmd/soft/serve/reap_linux.go

@@ -0,0 +1,42 @@
+//go:build linux
+
+package serve
+
+import (
+	"context"
+	"time"
+
+	"charm.land/log/v2"
+	"golang.org/x/sys/unix"
+)
+
+// reapZombies periodically reaps zombie child processes.
+//
+// When soft-serve runs as PID 1 in a container, orphaned descendant
+// processes (e.g. grandchild git pack-objects left behind when a git
+// parent exits before waiting for them) are reparented to PID 1.
+// Without an init system these processes become zombies because the
+// Go runtime only tracks children spawned via os/exec, not reparented
+// orphans. This goroutine periodically calls waitpid(-1, WNOHANG) to
+// clean them up.
+func reapZombies(ctx context.Context, logger *log.Logger) {
+	go func() {
+		ticker := time.NewTicker(10 * time.Second)
+		defer ticker.Stop()
+		for {
+			select {
+			case <-ctx.Done():
+				return
+			case <-ticker.C:
+				for {
+					var status unix.WaitStatus
+					pid, err := unix.Wait4(-1, &status, unix.WNOHANG, nil)
+					if err != nil || pid <= 0 {
+						break
+					}
+					logger.Debugf("reaped zombie child pid=%d status=%d", pid, status)
+				}
+			}
+		}
+	}()
+}

cmd/soft/serve/reap_other.go

@@ -0,0 +1,13 @@
+//go:build !linux
+
+package serve
+
+import (
+	"context"
+
+	"charm.land/log/v2"
+)
+
+// reapZombies is a no-op on non-Linux platforms.
+// See reap_linux.go for the Linux implementation.
+func reapZombies(_ context.Context, _ *log.Logger) {}

cmd/soft/serve/serve.go

@@ -75,6 +75,11 @@ var (
 				return fmt.Errorf("start server: %w", err)
 			}
 
+			// Start zombie child reaper for container environments where
+			// soft-serve may run as PID 1 without an init supervisor.
+			// See https://github.com/charmbracelet/soft-serve/issues/891
+			reapZombies(ctx, s.logger)
+
 			if syncHooks {
 				be := backend.FromContext(ctx)
 				if err := cmd.InitializeHooks(ctx, cfg, be); err != nil {