Merge branch 'nd/gc-lock-against-each-other'

* nd/gc-lock-against-each-other:
  gc: remove gc.pid file at end of execution

builtin/gc.c

@@ -14,6 +14,7 @@
 #include "cache.h"
 #include "parse-options.h"
 #include "run-command.h"
+#include "sigchain.h"
 #include "argv-array.h"
 
 #define FAILED_RUN "failed to run %s"
@@ -35,6 +36,21 @@ static struct argv_array repack = ARGV_ARRAY_INIT;
 static struct argv_array prune = ARGV_ARRAY_INIT;
 static struct argv_array rerere = ARGV_ARRAY_INIT;
 
+static char *pidfile;
+
+static void remove_pidfile(void)
+{
+	if (pidfile)
+		unlink(pidfile);
+}
+
+static void remove_pidfile_on_signal(int signo)
+{
+	remove_pidfile();
+	sigchain_pop(signo);
+	raise(signo);
+}
+
 static int gc_config(const char *var, const char *value, void *cb)
 {
 	if (!strcmp(var, "gc.packrefs")) {
@@ -179,6 +195,10 @@ static const char *lock_repo_for_gc(int force, pid_t* ret_pid)
 	FILE *fp;
 	int fd, should_exit;
 
+	if (pidfile)
+		/* already locked */
+		return NULL;
+
 	if (gethostname(my_host, sizeof(my_host)))
 		strcpy(my_host, "unknown");
 
@@ -219,6 +239,10 @@ static const char *lock_repo_for_gc(int force, pid_t* ret_pid)
 	strbuf_release(&sb);
 	commit_lock_file(&lock);
 
+	pidfile = git_pathdup("gc.pid");
+	sigchain_push_common(remove_pidfile_on_signal);
+	atexit(remove_pidfile);
+
 	return NULL;
 }
 

t/t6500-gc.sh

@@ -9,6 +9,11 @@ test_expect_success 'gc empty repository' '
 	git gc
 '
 
+test_expect_success 'gc does not leave behind pid file' '
+	git gc &&
+	test_path_is_missing .git/gc.pid
+'
+
 test_expect_success 'gc --gobbledegook' '
 	test_expect_code 129 git gc --nonsense 2>err &&
 	test_i18ngrep "[Uu]sage: git gc" err