From fad223d92ed34caac163695cc2a32cba80267c32 Mon Sep 17 00:00:00 2001
From: Andrew Kelley <andrew@ziglang.org>
Date: Wed, 12 Jun 2024 17:16:42 -0700
Subject: [PATCH] std.Progress: use a recursive mutex for stderr

---
 lib/std/Progress.zig | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/lib/std/Progress.zig b/lib/std/Progress.zig
index c7dffe4c3f..ef9099be99 100644
--- a/lib/std/Progress.zig
+++ b/lib/std/Progress.zig
@@ -521,6 +521,8 @@ fn windowsApiUpdateThreadRun() void {
 /// Allows the caller to freely write to stderr until `unlockStdErr` is called.
 ///
 /// During the lock, any `std.Progress` information is cleared from the terminal.
+///
+/// The lock is recursive; the same thread may hold the lock multiple times.
 pub fn lockStdErr() void {
     stderr_mutex.lock();
     clearWrittenWithEscapeCodes() catch {};
@@ -1378,4 +1380,7 @@ const have_sigwinch = switch (builtin.os.tag) {
     else => false,
 };
 
-var stderr_mutex: std.Thread.Mutex = .{};
+/// The primary motivation for recursive mutex here is so that a panic while
+/// stderr mutex is held still dumps the stack trace and other debug
+/// information.
+var stderr_mutex = std.Thread.Mutex.Recursive.init;