fix: silence embedded libghostty-vt logs

scripts/test_vendor_libghostty_vt.py

@@ -45,6 +45,14 @@ class VendorLibghosttyVtTests(unittest.TestCase):
         self.assertIn('"dist_archive"', text)
         self.assertIn('"extracted_dir"', text)
 
+    def test_embedded_libghostty_logging_is_silenced(self) -> None:
+        root = Path(__file__).resolve().parent.parent / "vendor" / "libghostty-vt"
+        lib_vt = root / "src" / "lib_vt.zig"
+        text = lib_vt.read_text()
+        self.assertIn("fn silentLog(", text)
+        self.assertIn(".log_level = .err", text)
+        self.assertIn(".logFn = silentLog", text)
+
 
 if __name__ == "__main__":
     unittest.main()

vendor/libghostty-vt/src/lib_vt.zig

@@ -242,6 +242,18 @@ comptime {
     }
 }
 
+fn silentLog(
+    comptime level: std.log.Level,
+    comptime scope: @Type(.enum_literal),
+    comptime format: []const u8,
+    args: anytype,
+) void {
+    _ = level;
+    _ = scope;
+    _ = format;
+    _ = args;
+}
+
 pub const std_options: std.Options = options: {
     if (builtin.target.cpu.arch.isWasm()) break :options .{
         // Wasm builds we specifically want to optimize for space with small
@@ -256,10 +268,13 @@ pub const std_options: std.Options = options: {
         .logFn = @import("os/wasm/log.zig").log,
     };
 
-    // For everything else we currently use defaults. Longer term I'm
-    // SURE this isn't right (e.g. we definitely want to customize the log
-    // function for the C lib at least).
-    break :options .{};
+    // Embedded libghostty-vt runs inside herdr's TUI process. Writing logs to
+    // stdout/stderr corrupts the ratatui surface, so silence library-side Zig
+    // logging by default for the C library build.
+    break :options .{
+        .log_level = .err,
+        .logFn = silentLog,
+    };
 };
 
 test {