Yet another dotnet format. It combines dotnet format with jscpd to provide a single action to run both. The main goal is to provide a way to handle dotnet format in a mono repo. You can have an action before this and create a matrix of projects to run this action on. And each project can have its own dotnet format config file.

• Dotnet format
• Mono repo support by using .dotnet-format.json (yml) config file to configure dotnet format
• Problem Matcher for dotnet format (only works when verbosity is set to detailed)
• JSCPD, can be configured with .jscpd.json (yml) file
• Generate reports as GitHub Action artifact
• Generate reports as comment on PR
• Generate reports as workflow summary
• (optional) commit changes
• (optional) update existing PR comment

This is a composite action — it orchestrates shell steps and actions/github-script, so there is no bundled JavaScript to build or ship.

• .NET SDK must be available on the runner (e.g. via actions/setup-dotnet). The included example fixtures target .NET 10.
• GitHub-hosted runners provide everything else it needs (bash, jq, git, Node/npx). On self-hosted runners make sure those are present.
• jscpd 5 — when jscpdCheck is enabled, the action uses a jscpd/cpd binary found on PATH, otherwise it fetches it on demand with npx --yes jscpd@5 (a one-time download). To avoid the download, install jscpd on the runner (npm i -g jscpd).
• YAML config (.dotnet-format.yml / .jscpd.yml) is converted on demand using yq if it is on PATH (GitHub-hosted runners ship it), otherwise a one-off pinned npx -y js-yaml@4.1.0; JSON config needs nothing extra.

Note on config keys: the granular options/styleOptions/analyzersOptions/whitespaceOptions blocks are toggled with isEnabled. The legacy misspelled isEabled key from older versions is no longer supported (breaking change) — use isEnabled.

• generate report as comment

  

• Workflow summary

  

• Annotation

  

Currently this action is focused on running on PRs. example:

• example workflow
• example dotnet-format config
• example jscpd config
• Action input

This is a composite action: action.yml wires together shell steps (which run dotnet format, jscpd, and git) and actions/github-script steps (which call the GitHub API and @actions/core). The error-prone pure logic — config merge, dotnet format argument building, and report→markdown — lives in small, dependency-free ES modules under scripts/ that the github-script steps load with a dynamic import(). There is no build step and nothing is bundled or committed to dist/.

Toolchain:

• pnpm as the package manager (packageManager field; CI uses pnpm/action-setup)
• Biome for linting + formatting (biome.json)
• node:test (Node's built-in runner) for the helper unit tests — no Jest, no transpile

pnpm install
pnpm lint           # biome lint
pnpm format-check   # biome check (lint + format + import order)
pnpm test           # node --test (unit tests for scripts/)
pnpm all            # everything CI runs (biome check + node --test)

Layout:

• scripts/*.mjs — pure, dependency-free helpers (merge, config read, format-args, report markdown), unit-tested
• scripts/steps/*.mjs — thin github-script wrappers (resolve-config, format-report, jscpd-report, comment)
• __tests__/*.test.mjs — node:test coverage for the pure helpers
• __tests__/dotnet/** — .NET 10 fixtures for the end-to-end workflow
• problem-matcher.json — referenced by action.yml via ${{ github.action_path }}

End-to-end behavior is exercised by .github/workflows/test-dotnet-format.yml against the net10.0 fixtures. See WALKTHROUGH.md for the design rationale and MIGRATION.md for the migration plan.

This project is based on / inspired by lots of other projects, including but not limited to:

• https://github.com/xt0rted/dotnet-format

• https://github.com/jfversluis/dotnet-format

• https://github.com/aclemmensen/dotnet-format-problem-matcher

• https://github.com/kucherenko/jscpd

• https://github.com/getunlatch/jscpd-github-action

• https://github.com/bibipkins/dotnet-test-reporter