std.debug.lockStderrWriter: also return ttyconf

`std.Io.tty.Config.detect` may be an expensive check (e.g. involving
syscalls), and doing it every time we need to print isn't really
necessary; under normal usage, we can compute the value once and cache
it for the whole program's execution. Since anyone outputting to stderr
may reasonably want this information (in fact they are very likely to),
it makes sense to cache it and return it from `lockStderrWriter`. Call
sites who do not need it will experience no significant overhead, and
can just ignore the TTY config with a `const w, _` destructure.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/Sema.zig b/src/Sema.zig
index 341cb1c855..4016041d82 100644
--- a/src/Sema.zig
+++ b/src/Sema.zig
@@ -2631,7 +2631,7 @@ pub fn failWithOwnedErrorMsg(sema: *Sema, block: ?*Block, err_msg: *Zcu.ErrorMsg
         Compilation.addModuleErrorMsg(zcu, &wip_errors, err_msg.*, false) catch @panic("out of memory");
         std.debug.print("compile error during Sema:\n", .{});
         var error_bundle = wip_errors.toOwnedBundle("") catch @panic("out of memory");
-        error_bundle.renderToStdErr(.{ .ttyconf = .no_color });
+        error_bundle.renderToStdErr(.{}, .auto);
         std.debug.panicExtra(@returnAddress(), "unexpected compile error occurred", .{});
     }