Path coverage, and branch coverage from LCOV

We now show path coverage for reports from Pebble with --path-coverage. A path is one route through a method, so path coverage tells you whether each combination of branches ran. It is low by nature, often about 5%, so it is shown next to Code Coverage and Branch Coverage and does not change them or your status checks. Read the path coverage docs.

You can find path coverage in these places, when your reports include it: a Path Coverage tile on the repository, commit and pull request pages, a path coverage line in the coverage chart (click the tile), a Paths column in the file list, a Paths row in the pull request comment, and the paths taken on each method in the file viewer, for example Paths 1/2. The method badge now sits on the line that declares the method.

With --path-coverage, Pebble also writes how many outcomes of each decision ran. The file viewer marks the lines where only some outcomes ran as partly covered, so you can see where the missing paths are.

LCOV reports now give branch coverage too, per file and per line, from their BRDA records. Istanbul-based tools (Jest, Vitest, nyc, c8) write these by default. For LCOV, clover_coverage in the API and analytics was always 100%, because LCOV has no statements. It now counts each line as a statement, so it is the share of lines and branches covered, as for Clover.

The API now returns path coverage: path_coverage, paths_total and paths_covered on commits, path in the repository coverage overview, and methods (branch rate and paths per method) in the file coverage endpoints.