███╗   ███╗██╗███╗   ██╗██████╗ ███████╗██████╗ ██████╗  ██████╗ 
 ████╗ ████║██║████╗  ██║██╔══██╗██╔════╝██╔══██╗██╔══██╗██╔═══██╗
 ██╔████╔██║██║██╔██╗ ██║██████╔╝█████╗  ██████╔╝██████╔╝██║   ██║
 ██║╚██╔╝██║██║██║╚██╗██║██╔══██╗██╔══╝  ██╔═══╝ ██╔══██╗██║   ██║
 ██║ ╚═╝ ██║██║██║ ╚████║██║  ██║███████╗██║     ██║  ██║╚██████╔╝
 ╚═╝     ╚═╝╚═╝╚═╝  ╚═══╝╚═╝  ╚═╝╚══════╝╚═╝     ╚═╝  ╚═╝ ╚═════╝ 

minrepro

Structure-aware JSON/YAML config shrinker: Find the smallest configuration snippet that still reproduces your bug.

---

⚡ What is minrepro? (In 15 Seconds)

When debugging huge Kubernetes manifests, Docker Compose files, CI workflows, or app configs, finding the exact offending line by hand is tedious and slow.

minrepro automates this delta debugging process:

1. Parses your configuration tree (JSON or YAML).
2. Runs your test command against the baseline to capture the exact failure.
3. Greedily removes unused keys and array items (largest subtrees first).
4. Keeps only deletions where your test still fails with that exact same error.
5. Outputs a minimal, valid config and a Markdown report with a unified diff!

🔍 Before vs. After Example

Original (100+ lines):

services:
  frontend:
    image: frontend:latest
    ports:
      - "3000:3000"
  backend:
    image: backend:latest
    environment:
      DATABASE_URL: postgres://db
      CACHE_URL: redis://cache
      BAD_OPTION: true
    volumes:
      - ./data:/data

After minrepro (Only what reproduces the failure):

services:
  backend:
    environment:
      BAD_OPTION: true

---

🚀 Quick Start

1. Install

pip install "git+https://github.com/dhrrishitvdeka/minrepro.git@v0.2.1"

Verify installation:

minrepro --version

2. Run on a Broken File

minrepro broken.yaml --test "my-tool --config {}" --error-contains "BAD_OPTION"

Note: The {} placeholder is automatically replaced by the path to each test candidate.

---

📋 Common Real-World Recipes

🐳 Docker Compose

Shrink a broken compose file that fails validation:

minrepro compose.yaml \
  --test "docker compose -f {} config" \
  --error-contains "service 'db' has invalid configuration"

☸️ Kubernetes Manifests

Isolate an invalid field in a large manifest using kubectl dry-run:

minrepro deployment.yaml \
  --test "kubectl apply --dry-run=server -f {}" \
  --error-contains "unknown field"

🤖 GitHub Actions Workflows

Isolate an invalid step or action in a .github/workflows/*.yml file using actionlint:

minrepro .github/workflows/ci.yml \
  --test "actionlint {}" \
  --error-contains "unexpected key"

📦 App Settings & JSON Payloads

Shrink an API request body or settings file:

minrepro payload.json \
  --test "python -m myapp.validate --input {}" \
  --diff

⚡ Direct In-Place Edit with Diff

Overwrite the file directly in place and display a colored terminal diff:

minrepro broken.yaml -t "pytest tests/test_config.py" --inplace --diff

---

🎛️ CLI Reference

minrepro INPUT --test "CMD with {}" [options]

Options Overview

Flag	Shorthand	Description
INPUT		Path to failing JSON or YAML file
--test CMD	-t CMD	Command to run ({} is replaced with the candidate path)
--output PATH	-o PATH	Output path for reduced config (default: <name>.min.<ext>)
--inplace	-i	Overwrite the input file directly with the reduced config
--diff	-d	Print a syntax-highlighted diff of all removed keys/lines
--check		Test whether the baseline fails without shrinking (exit 0 if fails, 1 if ok)
--env KEY=VAL	-e KEY=VAL	Set environment variable for the test subprocess (repeatable)
--report PATH	-r PATH	Path to Markdown report (default: <name>.minrepro.md)
--no-report		Do not generate a Markdown report
--stdout		Print the reduced config directly to stdout
--no-output		Do not write a reduced config file to disk
--format json|yaml		Force format (default: auto-detected)
--exit-code N		Require an exact exit code (default: any non-zero code)
--error-contains TEXT		Require this substring in command output (stdout + stderr)
--error-regex PATTERN		Require this regex to match command output
--timeout SEC		Per-run timeout in seconds (default: 60; 0 for none)
--max-steps N		Stop after N deletion attempts (for debugging)
--quiet	-q	Suppress progress output on stderr
--version		Show version and exit

Exit Codes

Code	Meaning
0	Success: Config reduced (or baseline is interesting when using --check).
1	Baseline Not Interesting: The original config does not trigger the specified failure.
2	Error: Invalid command-line arguments, parse failure, or configuration error.

---

🔍 How It Works

flowchart TD
  A[Load JSON or YAML] --> B[Parse Tree & Validate Baseline]
  B --> C{Does Baseline Fail?}
  C -->|No| D[Exit 1: Baseline not interesting]
  C -->|Yes| E[Collect Deletion Candidates<br/>Sorted by Subtree Weight]
  E --> F{Any Candidates Left?}
  F -->|No| G[Fixed-Point Reached]
  F -->|Yes| H[Delete One Key or List Item]
  H --> I[Write Temp Config & Run Test]
  I --> J{Still Shows Same Error?}
  J -->|Yes| K[Keep Deletion & Rescan Tree]
  J -->|No| L[Reject Deletion & Try Next]
  K --> F
  L --> F
  G --> M[Write Reduced Config + Markdown Report + Diff]

Loading

Same-Failure Safety Guarantee

minrepro ensures your reduction never "drifts" into a different error:

• Predicate Check: Must match --exit-code, --error-contains, and --error-regex if specified.
• Signature Anchoring: Distinguishes distinctive failure tokens from generic noise (e.g. emptying a file into a syntax error is automatically rejected).

---

🐍 Python Library API

Use minrepro programmatically in Python scripts, test harnesses, or CI pipelines:

from pathlib import Path
from minrepro import reduce_file, reduce_data, load

# 1. Reduce a file directly
result = reduce_file(
    "broken.yaml",
    command="python -m myapp.check --config {}",
    error_contains="BAD_OPTION",
)
print("Reduced YAML:")
print(result.reduced_text)

# 2. Reduce in-memory data
data, fmt, original_text = load(Path("broken.yaml"))
result = reduce_data(
    data,
    command="python -m myapp.check --config {}",
    fmt=fmt,
    original_text=original_text,
    error_contains="BAD_OPTION",
)
print(f"Removed {len(result.events)} items in {result.duration_seconds:.2f}s")

---

💻 Platforms & Cross-Platform Details

minrepro is written in pure Python with zero OS-specific binaries:

Area	Windows Behavior	POSIX (Linux / macOS) Behavior
Shell	cmd.exe via CreateProcess (shell=True)	/bin/sh / bash
Quoting	Double quotes with % escaping (%%)	Single quotes via shlex.quote
Temp Files	Closed before subprocess access (no lock conflicts)	Standard unlinking
Line Endings	Normalized to \n (UTF-8, no CRLF git noise)	Standard \n
Process Tree	taskkill /F /T on timeout	os.killpg(SIGKILL) on timeout

---

🛠️ Development & Contributing

# Clone and setup environment
git clone https://github.com/dhrrishitvdeka/minrepro.git
cd minrepro

# Install in editable mode with dev dependencies
pip install -e ".[dev]"

# Run test suite
pytest

---

📄 License

This project is licensed under the MIT License.