pager: fix order of atexit() calls

This is just a bug fix to git so that the pager won't close stdin/out
before other atexit functions run. The easy way to repro the bug is to
turn on GIT_TRACE_PERFORMANCE and run a command that runs the pager. Then
notice you don't get your performance data at the end. With this fix, you
do actually get the performance trace data.

Signed-off-by: Ben Peart <Ben.Peart@microsoft.com>

cache.h

@@ -1662,6 +1662,7 @@ extern void write_file(const char *path, const char *fmt, ...);
 
 /* pager.c */
 extern void setup_pager(void);
+extern void wait_for_pager_atexit(void);
 extern int pager_in_use(void);
 extern int pager_use_color;
 extern int term_columns(void);

git.c

@@ -782,6 +782,12 @@ int cmd_main(int argc, const char **argv)
 			cmd = slash + 1;
 	}
 
+	/*
+	 * wait_for_pager_atexit will close stdout/stderr so it needs to be
+	 * registered first so that it will execute last and not close the
+	 * handles until all other atexit handlers have finished
+	 */
+	atexit(wait_for_pager_atexit);
 	trace_command_performance(argv);
 
 	/*

pager.c

@@ -26,9 +26,12 @@ static void wait_for_pager(int in_signal)
 		finish_command(&pager_process);
 }
 
-static void wait_for_pager_atexit(void)
+
+static int run_wait_for_pager_atexit = 0;
+void wait_for_pager_atexit(void)
 {
-	wait_for_pager(0);
+	if (run_wait_for_pager_atexit)
+		wait_for_pager(0);
 }
 
 static void wait_for_pager_signal(int signo)
@@ -137,7 +140,7 @@ void setup_pager(void)
 
 	/* this makes sure that the parent terminates after the pager */
 	sigchain_push_common(wait_for_pager_signal);
-	atexit(wait_for_pager_atexit);
+	run_wait_for_pager_atexit = 1;
 }
 
 int pager_in_use(void)