filter out internal frame from stack trace

Author: edmundhung

packages/miniflare/src/plugins/core/errors/index.ts

@@ -3,7 +3,7 @@ import path from "path";
 import { fileURLToPath } from "url";
 import { z } from "zod";
 import { Request, Response } from "../../../http";
-import { Log } from "../../../shared";
+import { Log, processStackTrace } from "../../../shared";
 import { maybeParseURL } from "../../shared";
 import {
 	contentsToString,
@@ -235,7 +235,14 @@ export function reviveError(
 	error.stack = jsonError.stack;
 
 	// Try to apply source-mapping to the stack trace
-	error.stack = getSourceMappedStack(workerSrcOpts, error);
+	error.stack = processStackTrace(
+		getSourceMappedStack(workerSrcOpts, error),
+		(line, location) =>
+			!location.includes(".wrangler/tmp") &&
+			!location.includes("wrangler/templates/middleware")
+				? line
+				: null
+	);
 
 	return error;
 }
@@ -278,19 +285,6 @@ export async function handlePrettyErrorRequest(
 	const youch = new Youch();
 
 	youch.useTransformer((error) => {
-		error.frames = error.frames
-			.filter(
-				(frame) =>
-					!frame.fileName?.includes(".wrangler/tmp") &&
-					!frame.fileName?.includes("wrangler/templates/middleware")
-			)
-			.map((frame) => {
-				// To avoid Youch throwing an error if the frame has no fileName
-				// This happens in tests which hides some parts of the stack trace
-				frame.fileName ??= "";
-
-				return frame;
-			});
 		error.hint = [
 			'<a href="https://developers.cloudflare.com/workers/" target="_blank" style="text-decoration:none;font-style:normal;padding:5px">📚 Workers Docs</a>',
 			'<a href="https://discord.cloudflare.com" target="_blank" style="text-decoration:none;font-style: normal;padding:5px">💬 Workers Discord</a>',

packages/miniflare/src/plugins/core/modules.ts

@@ -30,9 +30,9 @@ const builtinModulesWithPrefix = builtinModules.concat(
 
 // Module identifier used if script came from `script` option
 export function buildStringScriptPath(workerIndex: number) {
-	return `script:${workerIndex}`;
+	return `script-${workerIndex}`;
 }
-const stringScriptRegexp = /^script:(\d+)$/;
+const stringScriptRegexp = /^script-(\d+)$/;
 export function maybeGetStringScriptPathIndex(
 	scriptPath: string
 ): number | undefined {

packages/miniflare/src/shared/log.ts

@@ -35,14 +35,40 @@ export function prefixError(prefix: string, e: any): Error {
 	return e;
 }
 
-function dimInternalStackLine(line: string): string {
-	if (
-		line.startsWith("    at") &&
-		(!line.includes(cwd) || line.includes(cwdNodeModules))
-	) {
-		return dim(line);
+// Regex matches V8 stack frame lines with and without function name:
+//   at fnName (file:line:col)
+//   at file:line:col
+const frameRegex = /^\s*at(?:\s+[^\s()]+)?\s*\(?(.+?)\)?$/;
+/**
+ * Processes a stack trace by applying a custom frame transformer.
+ * The transformer receives each frame line and its location (file:line:column);
+ * if it returns null, that frame is dropped; otherwise its return value replaces the line.
+ */
+export function processStackTrace(
+	stack: string,
+	transformFrame: (line: string, location: string) => string | null
+): string {
+	const lines = stack.split("\n");
+	const result: string[] = [];
+
+	for (const line of lines) {
+		const match = frameRegex.exec(line);
+
+		if (match) {
+			const location = match[1];
+			const transformed = transformFrame(line, location);
+			if (transformed !== null) {
+				result.push(transformed);
+			}
+
+			continue; // if transformed is null, drop the frame
+		}
+
+		// Non-frame lines (e.g., error message) are preserved
+		result.push(line);
 	}
-	return line;
+
+	return result.join("\n");
 }
 
 /**
@@ -60,11 +86,14 @@ export function formatError(error: Error): string {
 	let message: string;
 
 	if (error.stack) {
-		message = error.stack
-			.split("\n")
-			// Dim internal stack trace lines to highlight user code
-			.map(dimInternalStackLine)
-			.join("\n");
+		message = processStackTrace(error.stack, (line) => {
+			if (!line.includes(cwd) || line.includes(cwdNodeModules)) {
+				// Dim internal stack trace lines to highlight user code
+				return dim(line);
+			}
+
+			return line;
+		});
 	} else {
 		message = error.toString();
 	}

packages/miniflare/test/plugins/core/errors/index.spec.ts

@@ -352,7 +352,7 @@ test("responds with pretty error page", async (t) => {
 	t.regex(res.headers.get("Content-Type") ?? "", /^text\/html/);
 	const text = await res.text();
 	// ...including error, request method, URL and headers
-	t.regex(text, /Test error!/);
+	t.regex(text, /Unusual oops!/);
 	t.regex(text, /Method.+POST/is);
 	t.regex(text, /URL.+some-unusual-path/is);
 	t.regex(text, /X-Unusual-Key.+some-unusual-value/is);
@@ -361,12 +361,12 @@ test("responds with pretty error page", async (t) => {
 	const errorLogs = log.getLogs(LogLevel.ERROR);
 	t.deepEqual(errorLogs, [
 		`Error: Unusual oops!
-    at doSomething (script)
-    at Object.fetch (script)
+    at doSomething (script-0:6:12)
+    at Object.fetch (script-0:30:6)
 Caused by: Error: Test error
-    at oops (script)
-    at doSomething (script)
-    at Object.fetch (script)`,
+    at oops (script-0:13:11)
+    at doSomething (script-0:4:5)
+    at Object.fetch (script-0:30:6)`,
 	]);
 
 	// Check `fetch()` accepting HTML returns pretty-error page