ReproMin

Turn a large failing repository into a small, verified bug reproduction.

ReproMin is a repository-scale test-case reducer for repeatable Maven, Gradle, and Python failures. It removes files, manifest entries, source structure, and selected text only while the same failure still occurs.

Maintainer-run Gradle pilot: 854 -> 11 files, with the same failure reproduced in 5/5 fresh copies.

Start here

Run the self-contained demo to see a reduction complete in about 30 seconds. Already have a repeatable failure? Reduce it yourself. For a public, licensed Maven, Gradle, or Python case, share its exact revision, reproduction command, and target failure signal. A maintainer will check the fit and run a bounded first reduction; you do not need to install ReproMin.

30-second demo

With uv, run the published release without installing anything into your project or system Python:

uvx --from https://github.com/fly1d/repomin/releases/download/v0.1.0.dev13/repomin-0.1.0.dev13-py3-none-any.whl \
  repomin demo ./repomin-demo

The trusted, network-free demo normally finishes in a few seconds. Its key output looks like this:

ReproMin demo completed.
Reduced: 3 files / 855 bytes -> 2 files / 276 bytes in 14 attempts.
Removed: unused.txt and two unrelated input lines.
Validated: exact payload fingerprint.
Next: install ReproMin persistently, then check your repository with `repomin doctor SOURCE`.

The demo validates the reduced payload and leaves it with an evidence report for inspection. To use your own repeatable failure, continue with the real-repository quick start. The PowerShell walkthrough provides a self-contained Windows tour; the Chinese quick start covers the same real-repository path in Chinese. For a failing CI job, start with the GitHub Action.

Project status: ReproMin is a pre-alpha feasibility build. Use it on a reproducible failure in a repository you trust. The default host backend runs your command directly and is not a sandbox.

Evidence so far

Two maintainer-run pilots demonstrate the current technical scope:

Pilot	Before	After	Fresh-copy evidence
Gradle #38843	854 files, 3.8 MB	11 files, 87.9 KB	5/5 replays + cold start
tsdown #979	14 files	8 files	3/3 replays

These are feasibility results, not independent adoption or a promise that every repository will shrink by the same amount. The current milestone is five non-maintainer workflows.

When to use it

Use ReproMin when a bug already repeats but the repository is too large to share, review, or keep as a regression fixture. It produces a smaller payload, a human-readable receipt, and a machine-readable report that can be validated or replayed.

Your goal	Start with
Find the commit that introduced a regression	git bisect
Capture the runtime environment and dependencies	A container or ReproZip
Minimize source or compiler inputs	C-Reduce, C-Vise, Perses, or Shrink Ray
Shrink a build or application repository and retain evidence	ReproMin

ReproMin treats your build, test, or reproduction command as the authority. It does not diagnose the root cause or prove that the remaining code is correct.

Reduce a real failure

ReproMin requires Python 3.9+ and has no runtime dependencies. First run the reproduction command yourself and identify a marker that is specific to the target failure. Then, from a virtual environment, install the current pre-alpha release, check readiness, run a bounded reduction, and validate the exported evidence:

python -m pip install \
  "https://github.com/fly1d/repomin/releases/download/v0.1.0.dev13/repomin-0.1.0.dev13-py3-none-any.whl"

repomin doctor . \
  --command 'python -m pytest -q tests/test_checkout.py' \
  --match 'AssertionError: checkout total mismatch' \
  --exit-code 1 \
  --output ../checkout-repro

repomin reduce . \
  --command 'python -m pytest -q tests/test_checkout.py' \
  --match 'AssertionError: checkout total mismatch' \
  --exit-code 1 \
  --max-attempts 25 \
  --max-duration 300 \
  --output ../checkout-repro

repomin report validate ../checkout-repro.repomin/report.json \
  --payload ../checkout-repro \
  --format markdown

ReproMin itself prepares candidates in temporary copies and does not write into the source tree. On the host backend, however, your reproduction command still runs with your account and can modify any resource it can access. Do not use a generic marker such as FAILED, error, or only a test filename: an unrelated failure could satisfy it. The example requires both a distinctive failure message and its exact exit code. Before reducing, confirm that the target repeats and that setup errors or other failures do not emit the same marker. The quick start explains the complete real-repository workflow and the available exception and process signatures; use the Doctor guide for failed checks and the replay guide before executing an exported command.

For a repeatable CI failure, the GitHub Action can upload the reduced payload and validated report as workflow artifacts.

Current coverage

Layer	Coverage
Repository tree	Files and directories in any trusted local repository
Build manifests	Maven, Gradle, Python, Pipenv, Node, Composer, MSBuild, Bundler, Cargo, and Go
Source structure	Native Java and Python reducers
Selected text	Explicit UTF-8 files reduced by line
Custom semantic edits	Optional OpenAI-compatible HTTP integration; every edit still passes the oracle

Other languages still benefit from repository, manifest, and explicit text reduction. Start with the nearest ecosystem example.

Safety and privacy

The host backend runs the supplied command with your user account. It is not a sandbox. Only run repositories and commands you trust. Docker can reduce access when configured carefully, but it is not a complete security boundary. Read SECURITY.md before handling third-party code.

The Markdown validation summary is path-free and allow-listed, but it does not make the payload or full report safe to publish. Review every shared artifact.

Documentation and community

Documentation, Chinese quick start, Q&A, Share a result, Contribute, Starter tasks, Support

Apache-2.0 licensed. See LICENSE.