From e6b6a728b36335d9ac32dd216082aaf1faa6327e Mon Sep 17 00:00:00 2001
From: Andrew Kelley <andrew@ziglang.org>
Date: Tue, 9 Jul 2024 20:06:56 -0700
Subject: [PATCH] build runner: fix build summary painting over CLI progress

by obtaining the stderr lock when printing the build summary
---
 lib/compiler/build_runner.zig | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/lib/compiler/build_runner.zig b/lib/compiler/build_runner.zig
index ea1cfda266..7cc3d2bcd7 100644
--- a/lib/compiler/build_runner.zig
+++ b/lib/compiler/build_runner.zig
@@ -682,9 +682,12 @@ fn runStepNames(
     }
 
     const ttyconf = run.ttyconf;
-    const stderr = run.stderr;
 
     if (run.summary != .none) {
+        std.debug.lockStdErr();
+        defer std.debug.unlockStdErr();
+        const stderr = run.stderr;
+
         const total_count = success_count + failure_count + pending_count + skipped_count;
         ttyconf.setColor(stderr, .cyan) catch {};
         stderr.writeAll("Build Summary:") catch {};