From 1da7c93e4a6438a99f1f9339aa62ac51468b6fab Mon Sep 17 00:00:00 2001
From: Junseo Kim <semiwest2@gmail.com>
Date: Thu, 3 Sep 2026 23:56:54 +0900
Subject: [PATCH 1/2] fix(nextjs): Prevent sourceMappingURL stripping from
 truncating minified chunks

The regex in stripSourceMappingURLComments did not require the comment to
start at a line start, so sourceMappingURL-shaped text inside a string
literal of a minified (single-line) chunk matched, and everything from the
marker to EOF was deleted, leaving the chunk unparseable.

Anchor the match to a line start and exclude whitespace/quote characters
from the URL, matching how debug-id-upload.ts already reads the comment.
---
 packages/nextjs/src/config/handleRunAfterProductionCompile.ts | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/packages/nextjs/src/config/handleRunAfterProductionCompile.ts b/packages/nextjs/src/config/handleRunAfterProductionCompile.ts
index ae4b0a91d84a..8c8ed4af3ed8 100644
--- a/packages/nextjs/src/config/handleRunAfterProductionCompile.ts
+++ b/packages/nextjs/src/config/handleRunAfterProductionCompile.ts
@@ -137,8 +137,8 @@ async function warnAboutUncoveredSourcemaps(
   }
 }
 
-const SOURCEMAPPING_URL_COMMENT_REGEX = /\n?\/\/[#@] sourceMappingURL=[^\n]+$/;
-const CSS_SOURCEMAPPING_URL_COMMENT_REGEX = /\n?\/\*[#@] sourceMappingURL=[^\n]+\*\/$/;
+const SOURCEMAPPING_URL_COMMENT_REGEX = /(?:^|\n)\/\/[#@] sourceMappingURL=[^\s'"`]+$/;
+const CSS_SOURCEMAPPING_URL_COMMENT_REGEX = /(?:^|\n)\/\*[#@] sourceMappingURL=[^\n]+\*\/$/;
 
 /**
  * Strips sourceMappingURL comments from all JS/MJS/CJS/CSS files in the given directory.

From 9d762850fcc4084608c6b8a7bc096bed8aaeaf8f Mon Sep 17 00:00:00 2001
From: Junseo Kim <semiwest2@gmail.com>
Date: Thu, 3 Sep 2026 23:56:54 +0900
Subject: [PATCH 2/2] test(nextjs): Cover string-embedded sourceMappingURL
 markers in strip tests

---
 .../handleRunAfterProductionCompile.test.ts   | 42 +++++++++++++++++++
 1 file changed, 42 insertions(+)

diff --git a/packages/nextjs/test/config/handleRunAfterProductionCompile.test.ts b/packages/nextjs/test/config/handleRunAfterProductionCompile.test.ts
index ebff37a09c5a..5da39a04b2d0 100644
--- a/packages/nextjs/test/config/handleRunAfterProductionCompile.test.ts
+++ b/packages/nextjs/test/config/handleRunAfterProductionCompile.test.ts
@@ -740,4 +740,46 @@ describe('stripSourceMappingURLComments', () => {
       expect(content).not.toContain('sourceMappingURL');
     }
   });
+
+  it('does not modify minified files with a sourceMappingURL marker inside a string literal', async () => {
+    const filePath = path.join(tmpDir, 'chunks', 'minified.js');
+    const originalContent = `const worker = 'self.onmessage = () => {};\\n//# sourceMappingURL=worker.js.map\\n'; use(worker);`;
+    await fs.promises.writeFile(filePath, originalContent);
+
+    await stripSourceMappingURLComments(tmpDir);
+
+    const content = await fs.promises.readFile(filePath, 'utf-8');
+    expect(content).toBe(originalContent);
+  });
+
+  it('does not modify files ending with a template literal containing a sourceMappingURL marker', async () => {
+    const filePath = path.join(tmpDir, 'chunks', 'template.js');
+    const originalContent = 'const s = `line1\n//# sourceMappingURL=worker.js.map`;';
+    await fs.promises.writeFile(filePath, originalContent);
+
+    await stripSourceMappingURLComments(tmpDir);
+
+    const content = await fs.promises.readFile(filePath, 'utf-8');
+    expect(content).toBe(originalContent);
+  });
+
+  it('strips sourceMappingURL comment from files consisting only of the comment', async () => {
+    const filePath = path.join(tmpDir, 'chunks', 'comment-only.js');
+    await fs.promises.writeFile(filePath, '//# sourceMappingURL=comment-only.js.map');
+
+    await stripSourceMappingURLComments(tmpDir);
+
+    const content = await fs.promises.readFile(filePath, 'utf-8');
+    expect(content).toBe('');
+  });
+
+  it('strips sourceMappingURL comment with a data: URI', async () => {
+    const filePath = path.join(tmpDir, 'chunks', 'inline.js');
+    await fs.promises.writeFile(filePath, 'var a = 1;\n//# sourceMappingURL=data:application/json;base64,eyJ2IjozfQ==');
+
+    await stripSourceMappingURLComments(tmpDir);
+
+    const content = await fs.promises.readFile(filePath, 'utf-8');
+    expect(content).toBe('var a = 1;');
+  });
 });