[WRONG BRANCH] fix(crash-guard): preserve application fault visibility

src/lib/crash-guard.ts

@@ -176,9 +176,27 @@ export function isBenignAbortTeardown(err: unknown): boolean {
   const lockedStreamTeardown = err.message === "Invalid state: ReadableStream is locked"
     && (err as { code?: unknown }).code === "ERR_INVALID_STATE";
   if (!bareNullTeardown && !lockedStreamTeardown) return false;
+
+  const details = err as TypeError & {
+    sourceURL?: unknown;
+    line?: unknown;
+    column?: unknown;
+    originalLine?: unknown;
+    originalColumn?: unknown;
+  };
+  if (
+    (typeof details.sourceURL === "string" && details.sourceURL.length > 0)
+    || details.line !== undefined
+    || details.column !== undefined
+    || details.originalLine !== undefined
+    || details.originalColumn !== undefined
+  ) return false;
+
   const stack = err.stack ?? "";
-  // Native-only: no JS source frame. A real app TypeError would carry a `(file:line:col)` frame.
-  return !/\((?!native:)[^)]*:\d+:\d+\)/.test(stack);
+  // Native-only: no JS source frame, whether parenthesized or not.
+  return !stack.split(/\r?\n/).slice(1).some(line =>
+    /:\d+:\d+\)?\s*$/.test(line) && !/\bnative:\d+:\d+\)?\s*$/.test(line),
+  );
 }
 
 function record(kind: string, err: unknown, promise?: unknown): void {

tests/crash-guard.test.ts

@@ -108,6 +108,7 @@ describe("crash-guard diagnostics", () => {
 describe("benign abort-teardown classification", () => {
   test("flags the native-only bare TypeError as benign", () => {
     const err = new TypeError("null is not an object");
+    Object.assign(err, { sourceURL: "", line: undefined, column: undefined, originalLine: undefined, originalColumn: undefined });
     err.stack = "TypeError: null is not an object\n    at <anonymous> (native:1:11)\n    at processTicksAndRejections (native:7:39)";
     expect(isBenignAbortTeardown(err)).toBe(true);
   });
@@ -118,6 +119,19 @@ describe("benign abort-teardown classification", () => {
     expect(isBenignAbortTeardown(err)).toBe(false);
   });
 
+  test("does NOT flag a TypeError with an unparenthesized JS source frame", () => {
+    const err = new TypeError("null is not an object");
+    err.stack = "TypeError: null is not an object\n    at /abs/src/server.ts:120:13";
+    expect(isBenignAbortTeardown(err)).toBe(false);
+  });
+
+  test("does NOT flag a TypeError with hidden JSC source fields", () => {
+    const err = new TypeError("null is not an object");
+    err.stack = "TypeError: null is not an object\n    at <anonymous> (native:1:11)";
+    Object.assign(err, { sourceURL: "/abs/src/server.ts", originalLine: 120, originalColumn: 13 });
+    expect(isBenignAbortTeardown(err)).toBe(false);
+  });
+
   test("does NOT flag a different message or the (evaluating …) form", () => {
     const a = new TypeError("null is not an object (evaluating 'x.y')");
     a.stack = "TypeError: ...\n    at <anonymous> (native:1:11)";
@@ -136,7 +150,14 @@ describe("benign abort-teardown classification", () => {
 
   test("flags the native-only locked-ReadableStream sink-close teardown as benign (260712)", () => {
     const err = new TypeError("Invalid state: ReadableStream is locked");
-    (err as { code?: string }).code = "ERR_INVALID_STATE";
+    Object.assign(err, {
+      code: "ERR_INVALID_STATE",
+      sourceURL: "",
+      line: undefined,
+      column: undefined,
+      originalLine: undefined,
+      originalColumn: undefined,
+    });
     err.stack = "TypeError: Invalid state: ReadableStream is locked\n    at unknown\n    at <anonymous> (native:1:11)\n    at onSinkClose2 (native:5:32)";
     expect(isBenignAbortTeardown(err)).toBe(true);
   });