Module markers 

Source comment markers that exclude or tolerate a region of a file in coverage diff.

--ignore-filename-regex (and its coverage.yaml twin) drops a whole file from both reports, but the noise it exists to silence is almost always narrower than a file: one function gated on a runtime CPU-feature check is compiled into the denominator on every run yet executed only on a host that has the instruction, so it flips whenever the baseline and head runs draw different runner CPUs. Excluding the file hides far more real coverage than noise.

Naming the region in config is not an option either: line numbers are invalidated by every edit above them, and function extents are absent from the lcov FN: records (start line + mangled symbol only). So the region is delimited in the source itself, and each revision’s own source is scanned — head from the worktree, base from the base blob — which means no line number is ever stored, and a region that moves, grows, or disappears between base and head is handled by construction.

A region is opened by a comment naming a kind and a mandatory reason, and closed by an end comment; there is also a single-line form. The syntax is documented, with examples, in docs/coverage.md — deliberately not here: see INTRODUCER for why this file must not contain a literal marker.

Two kinds, differing in what they do to the reports:

• MarkerKind::Ignore — the lines are removed from both reports before any analysis, so they cannot move any number. The scoped twin of ignore-filename-regex.
• MarkerKind::Tolerate — the lines stay, so the percentage stays honest; only the delta signals are masked, by scoring each tolerated head line with its baseline hit status.

Matching is a plain substring on any line, so it works in any comment syntax and never depends on parsing the host language. A marker inside a string literal is therefore matched too — accepted, and documented.

Structs

FileMarkers

The regions of one file, plus the line sets they expand to.

Region

One marked region, as a 1-based inclusive line span.

Enums

MarkerKind

What a marked region does to the reports.

Constants

INTRODUCER

The literal that introduces every marker.

Functions

scan

Scans text for coverage markers, returning the regions in source order.