This is closely related to #853. See #853 for all test configuration, etc. info.

Whereas #853 describes that the XML coverage report generated from my merged coverage reports has reduced line hit counts in v0.18.0+ (vs v0.17.1), this issue is to track that the HTML report I am also generating shows zero coverage in v0.18.0+ (vs v0.17.1).

Expected behavior

v017.1 HTML report excerpt:

All Files (81.69% covered at 665.54 hits/line)
41 files in total. 5756 relevant lines. 4702 lines covered and 1054 lines missed

v017.1 XML report excerpt:

<coverage line-rate="0.82" branch-rate="0" lines-covered="4736" lines-valid="5792" branches-covered="0" branches-valid="0" complexity="0" version="0" timestamp="1580190755">

Actual behavior

v0.18.0 HTML report excerpt:

All Files ( 100.0% covered at 0.0 hits/line )
0 files in total.
0 relevant lines, 0 lines covered and 0 lines missed. ( 100.0% )

v0.18.0 XML report excerpt:

<coverage line-rate="0.15" branch-rate="0" lines-covered="867" lines-valid="5792" branches-covered="0" branches-valid="0" complexity="0" version="0" timestamp="1580254163">

Note that the above HTML and XML report excerpts are from the exact same CI build (and which also generated the coverage.xml excerpted in #853), so there seems to be some discrepancy in the reporting between the XML and HTML report formatters starting in v0.18.0.

Related Issues

#853 A separate symptom first observed concurrently with this issue. They seem like they are probably separate regressions, but not sure.