test: harden Windows CI output sanitization (#567) (thanks @erikpr1994)

test/setup.ts

@@ -9,34 +9,50 @@ function sanitizeWindowsCIOutput(text: string): string {
 }
 
 if (process.platform === "win32" && process.env.GITHUB_ACTIONS === "true") {
+  const decodeUtf8Text = (chunk: unknown): string | null => {
+    if (typeof chunk === "string") return chunk;
+    if (Buffer.isBuffer(chunk)) return chunk.toString("utf-8");
+    if (chunk instanceof Uint8Array)
+      return Buffer.from(chunk).toString("utf-8");
+    if (chunk instanceof ArrayBuffer)
+      return Buffer.from(chunk).toString("utf-8");
+    if (ArrayBuffer.isView(chunk)) {
+      return Buffer.from(
+        chunk.buffer,
+        chunk.byteOffset,
+        chunk.byteLength,
+      ).toString("utf-8");
+    }
+    return null;
+  };
+
   const originalStdoutWrite = process.stdout.write.bind(process.stdout);
   const originalStderrWrite = process.stderr.write.bind(process.stderr);
 
   process.stdout.write = ((chunk: unknown, ...args: unknown[]) => {
-    if (typeof chunk === "string") {
-      return originalStdoutWrite(sanitizeWindowsCIOutput(chunk), ...args);
-    }
-    if (Buffer.isBuffer(chunk)) {
-      return originalStdoutWrite(
-        sanitizeWindowsCIOutput(chunk.toString("utf-8")),
-        ...args,
-      );
-    }
-    return originalStdoutWrite(chunk as never, ...args);
+    const text = decodeUtf8Text(chunk);
+    if (text !== null)
+      return originalStdoutWrite(sanitizeWindowsCIOutput(text), ...args);
+    return originalStdoutWrite(chunk as never, ...args); // passthrough
   }) as typeof process.stdout.write;
 
   process.stderr.write = ((chunk: unknown, ...args: unknown[]) => {
-    if (typeof chunk === "string") {
-      return originalStderrWrite(sanitizeWindowsCIOutput(chunk), ...args);
-    }
-    if (Buffer.isBuffer(chunk)) {
-      return originalStderrWrite(
-        sanitizeWindowsCIOutput(chunk.toString("utf-8")),
-        ...args,
-      );
-    }
-    return originalStderrWrite(chunk as never, ...args);
+    const text = decodeUtf8Text(chunk);
+    if (text !== null)
+      return originalStderrWrite(sanitizeWindowsCIOutput(text), ...args);
+    return originalStderrWrite(chunk as never, ...args); // passthrough
   }) as typeof process.stderr.write;
+
+  const originalWriteSync = fs.writeSync.bind(fs);
+  fs.writeSync = ((fd: number, data: unknown, ...args: unknown[]) => {
+    if (fd === 1 || fd === 2) {
+      const text = decodeUtf8Text(data);
+      if (text !== null) {
+        return originalWriteSync(fd, sanitizeWindowsCIOutput(text), ...args);
+      }
+    }
+    return originalWriteSync(fd, data as never, ...(args as never[]));
+  }) as typeof fs.writeSync;
 }
 
 const originalHome = process.env.HOME;