Description

avivkeller

opened on Sep 21, 2024

Issue body actions

Version

v22.9.0

Platform

N/A

Subsystem

test_runner

What steps will reproduce the bug?

Create index.mjs:

export {}
//# sourceMappingURL=index.mjs.map

Create index.mjs.map:

{"version":3,"file":"index.mjs","sourceRoot":"","sources":["index.mjs"],"names":[],"mappings":"AAEA"}

Run:

node --experimental-test-coverage --test index.mjs

How often does it reproduce? Is there a required condition?

Every time.

What is the expected behavior? Why is that the expected behavior?

Coverage should be reported, or an error explaining why it wasn't is displayed.

What do you see instead?

ℹ Warning: Could not report code coverage. TypeError: Cannot read properties of undefined (reading 'startOffset')

Additional information

CC @nodejs/test_runner

Reacted by Spencer Snyder

Activity

1. avivkeller

   added

   confirmed-bugIssues and PRs for confirmed bugs.Issues and PRs for confirmed bugs.

   coverageIssues and PRs related to Node.js code coverage support.Issues and PRs related to Node.js code coverage support.

   source mapsIssues and PRs related to source map support.Issues and PRs related to source map support.

   test_runnerIssues and PRs related to the test runner subsystem.Issues and PRs related to the test runner subsystem.

   on Sep 21, 2024
2. geeksilva97 commented on Apr 21, 2025

   

   geeksilva97

   on Apr 21, 2025

   Contributor

   More actions

   It's not reproducible in 23.10.0

   Reacted by Aviv Keller, Pietro Marchini and Tejas Sathe
3. mcollina commented on May 23, 2026

   

   mcollina

   on May 23, 2026

   SponsorMember

   More actions

   I investigated this from a clean upstream/main build and could not reproduce it anymore.

   I checked out upstream/main, rebuilt node, and then ran the exact repro from the issue:

   ./node --experimental-test-coverage --test /tmp/.../index.mjs

   with:

   export {}
   //# sourceMappingURL=index.mjs.map

   and:

   {"version":3,"file":"index.mjs","sourceRoot":"","sources":["index.mjs"],"names":[],"mappings":"AAEA"}

   Current behavior is a normal coverage report:

   • index.mjs | 100.00 | 100.00 | 100.00
   • exit code 0

   So this no longer fails with:

   Warning: Could not report code coverage. TypeError: Cannot read properties of undefined (reading 'startOffset')
   

   The most likely fix is #55359, which made coverage only use sourcemap remapping when --enable-source-maps is explicitly enabled. That matches this repro, because it only used --experimental-test-coverage and --test.

   There was also related hardening in #55055 for invalid or missing sourcemaps.
4. mcollina

   closed this as completedon May 23, 2026

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