Merge branch 'ps/transport-helper-tsan-fix'

The TSAN race in transfer_debug() within transport-helper.c has been
resolved by initializing the debug flag early in
bidirectional_transfer_loop() before spawning worker threads, allowing
the removal of a TSAN suppression.

* ps/transport-helper-tsan-fix:
  transport-helper: fix TSAN race in transfer_debug()

.tsan-suppressions

@@ -7,7 +7,6 @@
 # A static variable is written to racily, but we always write the same value, so
 # in practice it (hopefully!) doesn't matter.
 race:^want_color$
-race:^transfer_debug$
 
 # A boolean value, which tells whether the replace_map has been initialized or
 # not, is read racily with an update. As this variable is written to only once,

transport-helper.c

@@ -1361,24 +1361,18 @@ int transport_helper_init(struct transport *transport, const char *name)
 /* This should be enough to hold debugging message. */
 #define PBUFFERSIZE 8192
 
+static int transfer_debug_enabled = -1;
+
 /* Print bidirectional transfer loop debug message. */
 __attribute__((format (printf, 1, 2)))
 static void transfer_debug(const char *fmt, ...)
 {
-	/*
-	 * NEEDSWORK: This function is sometimes used from multiple threads, and
-	 * we end up using debug_enabled racily. That "should not matter" since
-	 * we always write the same value, but it's still wrong. This function
-	 * is listed in .tsan-suppressions for the time being.
-	 */
-
 	va_list args;
 	char msgbuf[PBUFFERSIZE];
-	static int debug_enabled = -1;
 
-	if (debug_enabled < 0)
-		debug_enabled = getenv("GIT_TRANSLOOP_DEBUG") ? 1 : 0;
-	if (!debug_enabled)
+	if (transfer_debug_enabled < 0)
+		BUG("somebody forgot to check GIT_TRANSLOOP_DEBUG!");
+	if (!transfer_debug_enabled)
 		return;
 
 	va_start(args, fmt);
@@ -1648,6 +1642,9 @@ int bidirectional_transfer_loop(int input, int output)
 {
 	struct bidirectional_transfer_state state;
 
+	if (transfer_debug_enabled < 0)
+		transfer_debug_enabled = getenv("GIT_TRANSLOOP_DEBUG") ? 1 : 0;
+
 	/* Fill the state fields. */
 	state.ptg.src = input;
 	state.ptg.dest = 1;