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, 4 insertions, 5 deletions

diff --git a/lib/std/Build/WebServer.zig b/lib/std/Build/WebServer.zig
index 50e304c950..4a136ccbf4 100644
--- a/lib/std/Build/WebServer.zig
+++ b/lib/std/Build/WebServer.zig
@@ -54,9 +54,9 @@ pub fn notifyUpdate(ws: *WebServer) void {
 pub const Options = struct {
     gpa: Allocator,
     thread_pool: *std.Thread.Pool,
+    ttyconf: Io.tty.Config,
     graph: *const std.Build.Graph,
     all_steps: []const *Build.Step,
-    ttyconf: Io.tty.Config,
     root_prog_node: std.Progress.Node,
     watch: bool,
     listen_address: net.IpAddress,
@@ -101,10 +101,10 @@ pub fn init(opts: Options) WebServer {
     return .{
         .gpa = opts.gpa,
         .thread_pool = opts.thread_pool,
+        .ttyconf = opts.ttyconf,
         .graph = opts.graph,
         .all_steps = all_steps,
         .listen_address = opts.listen_address,
-        .ttyconf = opts.ttyconf,
         .root_prog_node = opts.root_prog_node,
         .watch = opts.watch,
 
@@ -236,9 +236,9 @@ pub fn finishBuild(ws: *WebServer, opts: struct {
             ws.gpa,
             ws.graph.io,
             ws.thread_pool,
+            ws.ttyconf,
             ws.all_steps,
             ws.root_prog_node,
-            ws.ttyconf,
             .{ .forever = .{ .ws = ws } },
         ) catch |err| std.process.fatal("failed to start fuzzer: {s}", .{@errorName(err)});
         ws.fuzz.?.start();
@@ -655,8 +655,7 @@ fn buildClientWasm(ws: *WebServer, arena: Allocator, optimize: std.builtin.Optim
     }
 
     if (result_error_bundle.errorMessageCount() > 0) {
-        const color = std.zig.Color.auto;
-        result_error_bundle.renderToStdErr(color.renderOptions());
+        result_error_bundle.renderToStdErr(.{}, .auto);
         log.err("the following command failed with {d} compilation errors:\n{s}", .{
             result_error_bundle.errorMessageCount(),
             try Build.Step.allocPrintCmd(arena, null, argv.items),