Merge branch 'jk/a-thread-only-dies-once'

A regression fix for the logic to detect die() handler triggering
itself recursively.

* jk/a-thread-only-dies-once:
  run-command: use thread-aware die_is_recursing routine
  usage: allow pluggable die-recursion checks

Author: gitster

git-compat-util.h

@@ -331,6 +331,7 @@ extern void warning(const char *err, ...) __attribute__((format (printf, 1, 2)))
 
 extern void set_die_routine(NORETURN_PTR void (*routine)(const char *err, va_list params));
 extern void set_error_routine(void (*routine)(const char *err, va_list params));
+extern void set_die_is_recursing_routine(int (*routine)(void));
 
 extern int prefixcmp(const char *str, const char *prefix);
 extern int suffixcmp(const char *str, const char *suffix);

run-command.c

@@ -588,6 +588,7 @@ int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const
 static pthread_t main_thread;
 static int main_thread_set;
 static pthread_key_t async_key;
+static pthread_key_t async_die_counter;
 
 static void *run_thread(void *data)
 {
@@ -614,6 +615,14 @@ static NORETURN void die_async(const char *err, va_list params)
 
 	exit(128);
 }
+
+static int async_die_is_recursing(void)
+{
+	void *ret = pthread_getspecific(async_die_counter);
+	pthread_setspecific(async_die_counter, (void *)1);
+	return ret != NULL;
+}
+
 #endif
 
 int start_async(struct async *async)
@@ -695,7 +704,9 @@ int start_async(struct async *async)
 		main_thread_set = 1;
 		main_thread = pthread_self();
 		pthread_key_create(&async_key, NULL);
+		pthread_key_create(&async_die_counter, NULL);
 		set_die_routine(die_async);
+		set_die_is_recursing_routine(async_die_is_recursing);
 	}
 
 	if (proc_in >= 0)

usage.c

@@ -6,8 +6,6 @@
 #include "git-compat-util.h"
 #include "cache.h"
 
-static int dying;
-
 void vreportf(const char *prefix, const char *err, va_list params)
 {
 	char msg[4096];
@@ -49,12 +47,19 @@ static void warn_builtin(const char *warn, va_list params)
 	vreportf("warning: ", warn, params);
 }
 
+static int die_is_recursing_builtin(void)
+{
+	static int dying;
+	return dying++;
+}
+
 /* If we are in a dlopen()ed .so write to a global variable would segfault
  * (ugh), so keep things static. */
 static NORETURN_PTR void (*usage_routine)(const char *err, va_list params) = usage_builtin;
 static NORETURN_PTR void (*die_routine)(const char *err, va_list params) = die_builtin;
 static void (*error_routine)(const char *err, va_list params) = error_builtin;
 static void (*warn_routine)(const char *err, va_list params) = warn_builtin;
+static int (*die_is_recursing)(void) = die_is_recursing_builtin;
 
 void set_die_routine(NORETURN_PTR void (*routine)(const char *err, va_list params))
 {
@@ -66,6 +71,11 @@ void set_error_routine(void (*routine)(const char *err, va_list params))
 	error_routine = routine;
 }
 
+void set_die_is_recursing_routine(int (*routine)(void))
+{
+	die_is_recursing = routine;
+}
+
 void NORETURN usagef(const char *err, ...)
 {
 	va_list params;
@@ -84,11 +94,10 @@ void NORETURN die(const char *err, ...)
 {
 	va_list params;
 
-	if (dying) {
+	if (die_is_recursing()) {
 		fputs("fatal: recursion detected in die handler\n", stderr);
 		exit(128);
 	}
-	dying = 1;
 
 	va_start(params, err);
 	die_routine(err, params);
@@ -102,12 +111,11 @@ void NORETURN die_errno(const char *fmt, ...)
 	char str_error[256], *err;
 	int i, j;
 
-	if (dying) {
+	if (die_is_recursing()) {
 		fputs("fatal: recursion detected in die_errno handler\n",
 			stderr);
 		exit(128);
 	}
-	dying = 1;
 
 	err = strerror(errno);
 	for (i = j = 0; err[i] && j < sizeof(str_error) - 1; ) {