One file for the next job
One file for reports and uploads.
For CI shards
Parallel tests.
One merged file.
Join exported .info shards into one report-ready LCOV file.
Where it fits
Tests to report
Merge exported shards before reporting.
Same result every time
Same output across input order and job count.
Choose the merge budget
Stream sorted files; configure sorting memory, workers, and temp space.
Install, then merge
GitHub Action or local binary.
02 Merge, then report
./lcovmerge coverage/shards/*.info -o coverage/merged.info
genhtml coverage/merged.info --output-directory coverage/htmlGitHub Actions
Merge downloaded artifacts in the final job.
- name: Merge LCOV shards
uses: megasoft1978/lcovmerge@v1.2.0
with:
files: coverage/shards/*.info
output: coverage/merged.infoGenerated workload benchmark
207 mssorted · 1 job145 mssorted · 4 jobs
Unsorted: 65 ms (1 job), 64 ms (4 jobs). Output bytes matched every run. One macOS arm64 host; results vary by workload.
Version 1.2.0 is the first Rust release.
Rust results & methodology ↗Report format
LCOV output works with your existing genhtml or upload step.
Limits
Exported .info only; no .gcda, .profraw, capture, reset, or reports. Native differs from lcov -a; profile 2.6 is experimental.
./lcovmerge --lcov-compat=2.6 -a 'coverage/shard-*.info' -o coverage/merged.infoSee the profile contract and full limits.