fix(daemon): carry --__daemonized identity marker through exec-restart (#2739)

cmd/ggcode/daemon.go

@@ -1668,10 +1668,21 @@ loop:
 		runfile.Remove(ses.ID)
 
 		var args []string
+		// #2739: exec-restart must carry the daemon identity marker, or
+		// daemonIdentityMatches (which keys on "--__daemonized" /
+		// "ggcode[") sees the restarted PID as an unrelated process that
+		// happens to reuse the PID, deletes the PID file, and admits a
+		// second daemon. ForkIntoBackground writes the same marker
+		// (internal/daemon/background.go:282). argv[0] display-name
+		// rewriting is deliberately NOT replicated: ExecSelf treats args
+		// as the flag list after argv[0], so an injected display name
+		// would become a stray positional argument and break cobra
+		// parsing. Contains-based identity matching needs the flag alone.
 		if cfgFile != "" {
 			args = append(args, "--config", cfgFile)
 		}
 		args = append(args, "daemon", "--follow")
+		args = append(args, "--__daemonized")
 		if ses.ID != "" {
 			args = append(args, "--resume", ses.ID)
 		}

cmd/ggcode/zz_issue2739_test.go

@@ -0,0 +1,42 @@
+package main
+
+// #2739 regression (cmd side): the exec-restart argv must carry
+// --__daemonized, or daemonIdentityMatches sees the restarted PID as an
+// unrelated process (PID-reuse false positive), deletes the PID file, and
+// admits a second daemon. This test pins that the daemon command accepts
+// the hidden flag combined with the exact restart flags exec-restart
+// builds; the identity-match half lives in internal/daemon (same-package
+// test hook access).
+
+import (
+	"testing"
+
+	"github.com/spf13/cobra"
+)
+
+func TestIssue2739_DaemonizedFlagParsesWithRestartFlags(t *testing.T) {
+	// The exact flag combination exec-restart builds:
+	// [--config X] daemon --follow --__daemonized [--resume ID] [--bypass] ...
+	root := NewRootCmd()
+	// The flags live on the daemon subcommand; locate it like a real
+	// invocation would.
+	var daemonCmd *cobra.Command
+	for _, c := range root.Commands() {
+		if c.Name() == "daemon" {
+			daemonCmd = c
+			break
+		}
+	}
+	if daemonCmd == nil {
+		t.Fatalf("daemon subcommand not found")
+	}
+	if err := daemonCmd.ParseFlags([]string{
+		"--follow", "--__daemonized", "--bypass",
+	}); err != nil {
+		t.Fatalf("exec-restart flag combo must parse: %v", err)
+	}
+	f := daemonCmd.Flags()
+	if v, _ := f.GetBool("__daemonized"); !v {
+		t.Fatalf("__daemonized must be settable via combined restart argv")
+	}
+}

internal/daemon/zz_issue2739_test.go

@@ -0,0 +1,37 @@
+package daemon
+
+// #2739 regression (identity side): a daemon restarted via exec-restart
+// carries --__daemonized in its rebuilt argv; daemonIdentityMatches must
+// recognize it (and must NOT recognize a marker-less cmdline - that is the
+// PID-reuse false positive that deletes the PID file and admits a second
+// daemon).
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestIssue2739_IdentityMatchesRestartedCmdline(t *testing.T) {
+	orig := testProcessCmdline
+	t.Cleanup(func() { testProcessCmdline = orig })
+
+	// Simulated /proc/<pid>/cmdline after exec-restart with the fix.
+	cmdline := strings.Join([]string{
+		"/usr/local/bin/ggcode", "--config", "/home/u/.ggcode/ggcode.yaml",
+		"daemon", "--follow", "--__daemonized", "--resume", "abc123",
+	}, "\x00")
+	testProcessCmdline = func(int) string { return cmdline }
+	if !daemonIdentityMatches(1234, "/home/u/proj") {
+		t.Fatalf("restarted daemon cmdline with --__daemonized must match identity")
+	}
+
+	// Without the marker (the pre-fix bug): identity must NOT match, so a
+	// live restarted daemon was misjudged as PID reuse.
+	noMarker := strings.Join([]string{
+		"/usr/local/bin/ggcode", "--config", "/x.yaml", "daemon", "--follow",
+	}, "\x00")
+	testProcessCmdline = func(int) string { return noMarker }
+	if daemonIdentityMatches(1234, "/home/u/proj") {
+		t.Fatalf("cmdline without markers must not match daemon identity")
+	}
+}