From 6db0ad26e3ff08c3ad828fb19643b50146172e09 Mon Sep 17 00:00:00 2001
From: Snider <snider@host.uk.com>
Date: Tue, 14 Apr 2026 19:44:06 +0100
Subject: [PATCH] fix(registry): idempotent Unregister/Release when file
 missing

The coreio.Local.Delete error wraps the underlying os.ErrNotExist
through core.E, so the prior os.IsNotExist check on the registry
Unregister path never matched. Same wrapping broke the daemon
Stop path that relied on pidfile.Release being a no-op for absent
files.

Switch both to coreio.Local.Exists before Delete, which is the
idempotent pattern the callers already assume. Adds coverage for
TestPIDFile_Release_MissingIsNoop and fixes TestRegistry_Unregister
MissingIsNoop.

Co-Authored-By: Virgil <virgil@lethean.io>
---
 pidfile.go      | 4 ++++
 pidfile_test.go | 6 ++++++
 registry.go     | 9 +++++----
 3 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/pidfile.go b/pidfile.go
index bade76f..df9b965 100644
--- a/pidfile.go
+++ b/pidfile.go
@@ -67,6 +67,7 @@ func (p *PIDFile) Acquire() error {
 }
 
 // Release removes the PID file.
+// Returns nil if the PID file does not exist.
 //
 // Example:
 //
@@ -74,6 +75,9 @@ func (p *PIDFile) Acquire() error {
 func (p *PIDFile) Release() error {
 	p.mu.Lock()
 	defer p.mu.Unlock()
+	if !coreio.Local.Exists(p.path) {
+		return nil
+	}
 	if err := coreio.Local.Delete(p.path); err != nil {
 		return core.E("pidfile.release", "failed to remove PID file", err)
 	}
diff --git a/pidfile_test.go b/pidfile_test.go
index abdfa29..a35c9cb 100644
--- a/pidfile_test.go
+++ b/pidfile_test.go
@@ -47,6 +47,12 @@ func TestPIDFile_Path_Good(t *testing.T) {
 	assert.Equal(t, "/tmp/test.pid", pid.Path())
 }
 
+func TestPIDFile_Release_MissingIsNoop(t *testing.T) {
+	pidPath := core.JoinPath(t.TempDir(), "absent.pid")
+	pid := NewPIDFile(pidPath)
+	require.NoError(t, pid.Release())
+}
+
 func TestReadPID_Missing_Bad(t *testing.T) {
 	pid, running := ReadPID("/nonexistent/path.pid")
 	assert.Equal(t, 0, pid)
diff --git a/registry.go b/registry.go
index 0c091c4..76d0247 100644
--- a/registry.go
+++ b/registry.go
@@ -88,10 +88,11 @@ func (r *Registry) Register(entry DaemonEntry) error {
 //
 //	_ = reg.Unregister("app", "serve")
 func (r *Registry) Unregister(code, daemon string) error {
-	if err := coreio.Local.Delete(r.entryPath(code, daemon)); err != nil {
-		if os.IsNotExist(err) {
-			return nil
-		}
+	path := r.entryPath(code, daemon)
+	if !coreio.Local.Exists(path) {
+		return nil
+	}
+	if err := coreio.Local.Delete(path); err != nil {
 		return coreerr.E("Registry.Unregister", "failed to delete entry file", err)
 	}
 	return nil