Ensure that socket file is free when starting job api server

jobapi/server.go

@@ -36,10 +36,7 @@ func NewServer(socketPath string, environ env.Environment) (server *Server, toke
 	}
 
 	if exists {
-		err = os.RemoveAll(socketPath)
-		if err != nil {
-			return nil, "", fmt.Errorf("removing existing socket: %w", err)
-		}
+		return nil, "", fmt.Errorf("creating server: file already exists at socket path %s", socketPath)
 	}
 
 	token, err = generateToken(32)

jobapi/server_test.go

@@ -90,6 +90,30 @@ func TestServerStartStop(t *testing.T) {
 	}
 }
 
+func TestServerStartStop_WithPreExistingSocket(t *testing.T) {
+	sockName := path.Join(os.TempDir(), "test-socket-collision.sock")
+	srv1, _, err := jobapi.NewServer(sockName, env.Environment{})
+	if err != nil {
+		t.Fatalf("expected initial server creation to succeed, got %v", err)
+	}
+
+	err = srv1.Start()
+	if err != nil {
+		t.Fatalf("expected initial server start to succeed, got %v", err)
+	}
+	defer srv1.Stop()
+
+	expectedErr := fmt.Sprintf("creating server: file already exists at socket path %s", sockName)
+	_, _, err = jobapi.NewServer(sockName, env.Environment{})
+	if err == nil {
+		t.Fatalf("expected second server creation to fail with %s, got nil", expectedErr)
+	}
+
+	if err.Error() != expectedErr {
+		t.Fatalf("expected second server start to fail with %v, got %v", expectedErr, err)
+	}
+}
+
 type apiTestCase[Req, Resp any] struct {
 	name                 string
 	requestBody          *Req