Support glob/multiple Cobertura files (or action-side merge) in the file input

[glen-84]

Summary

The file input accepts a single Cobertura XML report. Projects with a test matrix or monorepo layout produce many per-project Cobertura files, so they must be merged into one file before this action can consume them. It would help if the action accepted multiple files / a glob / a directory and merged them itself.

Current behavior

• file is a single, required path to one Cobertura XML report.
• There is no glob, multi-file, or directory input.

Desired behavior

Accept any one of:

• glob patterns in file (e.g. **/*.cobertura.xml), or
• a files input taking a newline- or comma-separated list, or
• a directory + pattern,

and merge the matched reports (action-side or server-side) before upload. For comparison, codecov/codecov-action accepts multiple files / directory search, so matrix and monorepo setups upload without a separate merge step.

Use case

We're migrating a public .NET OSS monorepo (ChilliCream/graphql-platform) from Codecov to GitHub Code Quality. CI runs a 125-project test matrix, and each job emits its own *.cobertura.xml artifact. Codecov merged them server-side. With this action we now add an explicit merge step first:

- run: dotnet tool install --global dotnet-coverage
- run: >
    dotnet-coverage merge
    --output merged.cobertura.xml
    --output-format cobertura
    "**/*.cobertura.xml"
- uses: actions/upload-code-coverage@v1
  with:
    file: merged.cobertura.xml
    language: "C#"
    label: code-coverage/dotnet

This works, but native multi-file/glob support (or an action-side merge) would remove the extra tooling and step for the common matrix/monorepo case.

Question

If multiple uploads with distinct labels are made (e.g. one per matrix job), are they aggregated into a single PR coverage total, or treated independently? If aggregation already works that way, documenting it would cover much of this need on its own.

Drafted by Claude (Anthropic AI assistant).