From 3e456d4bb0ca04f901f7fdb359a8d9bfb65c4f0b Mon Sep 17 00:00:00 2001
From: Jarred Sumner <jarred@jarredsumner.com>
Date: Wed, 30 Jul 2025 00:09:42 -0700
Subject: [PATCH] Disable `findSourceMap` when `--enable-source-maps` is not
 passed (#21478)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

### What does this PR do?

Fixes the error printed:
```js
❯ bun --bun dev
$ next dev --turbopack
   ▲ Next.js 15.4.5 (Turbopack)
   - Local:        http://localhost:3000
   - Network:      http://192.168.1.250:3000

 ✓ Starting...
 ✓ Ready in 637ms
 ○ Compiling / ...
 ✓ Compiled / in 1280ms
/private/tmp/empty/my-app/.next/server/chunks/ssr/[root-of-the-server]__012ba519._.js: Invalid source map. Only conformant source maps can be used to filter stack frames. Cause: TypeError: payload is not an Object. (evaluating '"sections" in payload')
/private/tmp/empty/my-app/.next/server/chunks/ssr/[root-of-the-server]__93bf7db5._.js: Invalid source map. Only conformant source maps can be used to filter stack frames. Cause: TypeError: payload is not an Object. (evaluating '"sections" in payload')
 GET / 200 in 1416ms
^C^[[A
```

### How did you verify your code works?
---
 src/sourcemap/JSSourceMap.zig | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/src/sourcemap/JSSourceMap.zig b/src/sourcemap/JSSourceMap.zig
index 21c5c10b90..3222d56ffd 100644
--- a/src/sourcemap/JSSourceMap.zig
+++ b/src/sourcemap/JSSourceMap.zig
@@ -6,10 +6,22 @@ sourcemap: *bun.sourcemap.ParsedSourceMap,
 sources: []bun.String = &.{},
 names: []bun.String = &.{},
 
+/// TODO: when we implement --enable-source-map CLI flag, set this to true.
+pub var @"--enable-source-maps" = false;
+
 fn findSourceMap(
     globalObject: *JSGlobalObject,
     callFrame: *CallFrame,
 ) bun.JSError!JSValue {
+    // Node.js doesn't enable source maps by default.
+    // In Bun, we do use them for almost all files since we transpile almost all files
+    // If we enable this by default, we don't have a `payload` object since we don't internally create one.
+    // This causes Next.js to emit errors like the below on start:
+    //       .next/server/chunks/ssr/[root-of-the-server]__012ba519._.js: Invalid source map. Only conformant source maps can be used to filter stack frames. Cause: TypeError: payload is not an Object. (evaluating '"sections" in payload')
+    if (!@"--enable-source-maps") {
+        return .js_undefined;
+    }
+
     const source_url_value = callFrame.argument(0);
     if (!source_url_value.isString()) {
         return .js_undefined;