A source file carries one istanbul statement map per Vite environment, so a
node suite and a jsdom suite that load the same module enter the merged
report through two maps that spell one statement differently. istanbul
reconciles those overlapping ranges by attributing the hits of the narrowest
containing range, but only while a location carries numeric line and column
values. ast-v8-to-istanbul ends a whole-line statement at column Infinity, and
the partition blob serializes Infinity as null, so the merge command kept the
client-only spelling as an extra, unhit statement: a file whose every statement
ran reported 96.96% and failed the per-file 100% gate.
The coordinator now passes each partition a reporter whose onCoverage hook
rewrites every non-finite end column to a finite line-end column before the
blob is written, which restores that reconciliation without weakening the
gate. The uncovered-locations reporter reads the same column as a line end.
The per-file 100% thresholds name only the failing file. A custom istanbul
reporter now prints one clickable path:line:col record per uncovered
statement, branch path, and function, right above the threshold errors, in
both the CI coverage lane and local test:coverage runs (they share this
config). CJS because istanbul-reports loads custom reporters with a bare
require() outside the tsx/ESM pipeline.
Tianyi Cui