• Version: v12.1.0
• Platform: Fedora 28 (Twenty Eight)
• Subsystem: test

This took me a while to figure out, and is potentially in the V8 engine.

In Node 12, block coverage seems to be dropped for some functions, on some platforms.

Here's an example:

• this coverage output is generated on Fedora with [email protected], by running the test suite for this library.
• this coverage output is generated from an identical run on [email protected].

The main difference between the two test runs is that coverage for generateChangelogEntry is missing in the output from Fedora (this is a serious issue, because from a test reporter point of view, generateChangelogEntry will appear as covered).

• tracking issue on V8: https://bugs.chromium.org/p/v8/issues/detail?id=9212
• tracking issue on c8: bug: coverage reported incorrectly with source-maps on Node 12 bcoe/c8#90

Additional Information

• this problem seemed to also occur on 11.14.0 on Fedora on @coreyfarrell's computer, but not 11.15.0; @coreyfarrell was unable to reproduce on >11.10.0 with further testing.

CC: @joyeecheung @hashseed @schuay, was wondering if you might have any thoughts on this one ... I could imagine it possibly being an issue in V8, or potentially a race condition during the bootstrapping of coverage in Node.js.