Generating a report from multiple `nextest-archive` runs

[BatmanAoD]

We are using separate nextest archives for separate feature-sets, and we'd like cargo llvm-cov report to be able to create a combined report from the separate archives. It appears that the report command only permits a single --nextest-archive-file argument.

• we nextest-archive each --feature, using a common target directory target/llvm-cov-target/`
• for each nextest archive, we run llvm-cov nextest in a separate CI job
• a subsequent job collects all of the profraw files and puts them under target/llvm-cov-target/.
• we then attempt to generate a coverage report using that directory:

So we'd like to be able to do cargo llvm-cov report --nextest-archive-file <file1> --nextest-archive-file <file2>.

[BatmanAoD]

Related feature request in nextest itself: nextest-rs/nextest#2233

[taiki-e]

Does the existing method not work?

[BatmanAoD]

@taiki-e That doesn't appear to be compatible with the --nextest-archive option; or is it? It appears to assume that the tests are in a consolidated directory already.