pronto-rubycritic

A production-grade Pronto runner for RubyCritic. It reports reek / flay / flog / complexity / churn issues as Pronto messages — only on lines added or changed in the pull request, never on untouched code.

New in 0.12.0 — forensic refactor: real working filters for flay/flog scores, safe YAML loading, GitHub/GitLab auto-detection, six independently-tested modules, and ≥90 % line-coverage CI gates.

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Table of contents

• Why this gem
• At a glance
• Installation
• Quickstart
• Configuration
• Environment variables
• CI integration
• Architecture
• Development
• Troubleshooting
• Migrating from 0.11.x
• Contributing
• License

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Why this gem

Running the full RubyCritic report on every PR is noisy — contributors get flagged for code they never touched. This gem scopes RubyCritic output to diff-changed lines, making it actionable:

• Only added / modified lines are flagged. A smell on line 42 that existed before the PR is silently ignored; a smell introduced by the PR on line 7 is reported as a Pronto message.
• Every RubyCritic analyser is supported — reek, flay, flog, complexity, churn — behind one config file.
• Per-CI formatting. GitHub renders HTML <details> blocks in PR comments; GitLab gets plain Markdown (detected automatically).
• Fails loud in CI when asked, fails soft in local dev. Set PRONTO_RUBYCRITIC_RAISE_ERRORS=1 in CI to surface runner bugs; locally the runner degrades to an empty result set with a stderr warning.

At a glance

Ruby	≥ 3.2.2
Pronto	≥ 0.11, < 2.0
RubyCritic	≥ 4.9, < 6.0
Analysers	reek · flay · flog · complexity · churn
Output modes	GitHub HTML · GitLab Markdown · Plain
Tests	RSpec · 123 examples · ≥ 90 % line coverage (enforced)
Lint	RuboCop · Reek · RubyCritic (self-analysis)
CI	GitHub Actions (3.2 / 3.3 / 3.4 / 4.0) + GitLab CI
License	MIT

Installation

Add to your Gemfile:

gem 'pronto-rubycritic', '~> 0.12', require: false

Then:

bundle install

Or install standalone:

gem install pronto-rubycritic

Quickstart

Run on the current diff:

bundle exec pronto run -r rubycritic

Run on the last N commits:

bundle exec pronto run -r rubycritic -c HEAD~3

Run against a specific commit range (CI-friendly):

bundle exec pronto run -r rubycritic --commit="origin/main" -f github_pr -c origin/main

Example output

Given a PR that introduces a smell on a new line, the local / plain output looks like this (Pronto prefixes each message with path:line and a level letter):

app/services/order.rb:42 W: [warning] FeatureEnvy — Order#calculate_total (reek)
  Message:     Order#calculate_total refers to 'customer' more than self
  Locations:   app/services/order.rb:42
  Complexity:  14.50  Duplication: 0  Methods: 7  Cost: 2.10  Churn: 3
  Docs:        https://github.com/troessner/reek/blob/master/docs/Feature-Envy.md

Under GitHub Actions the same finding is posted as an inline PR review comment with a severity emoji, the smell type, a collapsible <details> metrics table, and a docs link; under GitLab CI it is the same content rendered as flat Markdown (a single-row metrics table, no <details>). See the output differences table below.

Configuration

Create .rubycritic-pronto.yml at your repo root. All keys are optional — an empty file (or no file at all) reports every smell on changed lines at the default severity.

# Filter by reek smell type and cap total smells per module.
reek:
  smell_types:
    - FeatureEnvy
    - UncommunicativeMethodName
    - UncommunicativeVariableName
    - DuplicateMethodCall
    - LongParameterList
  max_smells: 5            # cap total smells per module (all analysers)

# Drop flay smells above this duplication-mass score.
flay:
  max_score: 100
  exclude:
    - 'spec/**/*'
    - 'db/migrate/**/*'

# Drop flog smells above this complexity score.
flog:
  max_score: 20
  exclude:
    - 'spec/**/*'

# Drop entire modules above these thresholds.
complexity:
  max: 10

churn:
  max: 5

Configuration keys reference

Key	Scope	Behaviour
reek.smell_types	reek smells only	Allow-list of reek smell type names. Non-listed reek smells are dropped. flay/flog smells are unaffected.
reek.max_smells	all smells per module	Cap total reported smells per module.
flay.max_score	flay smells only	Drop flay smells with score > max_score.
flay.exclude	flay smells only	Repo-relative globs (FNM_PATHNAME) to skip.
flog.max_score	flog smells only	Drop flog smells with score > max_score.
flog.exclude	flog smells only	Same as flay.exclude.
complexity.max	module	Drop modules with complexity > max.
churn.max	module	Drop modules with churn > max.

Recognised reek smell types

Use any of these under reek.smell_types:

Attribute · BooleanParameter · ClassVariable · ControlParameter · DataClump
DuplicateMethodCall · FeatureEnvy · InstanceVariableAssumption
IrresponsibleModule · LongParameterList · LongYieldList · ManualDispatch
MissingSafeMethod · ModuleInitialize · NestedIterators · NilCheck
RepeatedConditional · SelfAssignment · SingletonMethodCall · TooManyConstants
TooManyInstanceVariables · TooManyMethods · UncommunicativeMethodName
UncommunicativeModuleName · UncommunicativeParameterName
UncommunicativeVariableName · UnusedParameters · UnusedPrivateMethod
UtilityFunction

Environment variables

Variable	Default	Purpose
PRONTO_RUBYCRITIC_SEVERITY_LEVEL	warning	Severity of emitted messages: info, warning, error, or fatal.
PRONTO_RUBYCRITIC_DEBUG	unset	Set to 1/true/yes/on to print the first 10 backtrace lines on any internal error.
PRONTO_RUBYCRITIC_RAISE_ERRORS	unset	Set to 1/true/yes/on to re-raise internal errors instead of returning []. Recommended in CI.
PRONTO_REEK_SEVERITY_LEVEL	unset	Deprecated. Read for back-compat with a deprecation warning. Use PRONTO_RUBYCRITIC_SEVERITY_LEVEL.

Severity can also be set in .pronto.yml:

# .pronto.yml
rubycritic:
  severity_level: warning

Precedence: PRONTO_RUBYCRITIC_SEVERITY_LEVEL → PRONTO_REEK_SEVERITY_LEVEL (deprecated) → .pronto.yml → :warning default.

CI integration

GitHub Actions

The runner auto-detects $GITHUB_ACTIONS and emits rich HTML with <details> blocks. Example step:

- name: Pronto
  env:
    PRONTO_PULL_REQUEST_ID: ${{ github.event.pull_request.number }}
    PRONTO_GITHUB_ACCESS_TOKEN: ${{ secrets.GITHUB_TOKEN }}
    PRONTO_RUBYCRITIC_RAISE_ERRORS: '1'
  run: |
    bundle exec pronto run -f github_pr -c origin/${{ github.base_ref }}

GitLab CI

The runner auto-detects $GITLAB_CI and emits plain Markdown (GitLab discussion comments do not render <details> reliably). Example:

pronto:
  stage: lint
  script:
    - bundle exec pronto run -f gitlab_mr -c origin/$CI_MERGE_REQUEST_TARGET_BRANCH_NAME
  variables:
    PRONTO_GITLAB_API_PRIVATE_TOKEN: $PRONTO_GITLAB_TOKEN
    PRONTO_RUBYCRITIC_RAISE_ERRORS: '1'

Output differences table

Feature	GitHub Actions	GitLab CI	Local CLI
Markup	HTML <details> + table	Flat Markdown table	Indented plain text
Source location	Anchored to the diff line	Anchored to the diff line	Printed on a Locations: line
Detected via	$GITHUB_ACTIONS	$GITLAB_CI	neither

Architecture

Pronto::RubyCritic (Runner)
├── ConfigLoader     — safe YAML + severity resolution
├── Analyser         — owns ::RubyCritic::Config global, runs AnalysersRunner
├── SmellFilter      — pure filter against user config
├── MessageBuilder   — maps smells → Pronto::Message on added lines
└── Formatter        — GitHub HTML / GitLab Markdown / Plain

Each module has its own spec file (spec/pronto/rubycritic/*_spec.rb) and mocks only the boundary between layers. Integration tests in spec/integration/ exercise the full runner end-to-end against real fixtures.

See CHANGELOG.md for the rationale behind every change in 0.12.0.

Development

git clone https://github.com/Rishabhs343/custom-pronto-gem.git
cd custom-pronto-gem
bundle install

bundle exec rake              # RuboCop + RSpec
bundle exec rake ci           # RuboCop + Reek + RSpec + RubyCritic (full CI)
bundle exec rake reek         # Reek only
bundle exec rake critic       # RubyCritic self-analysis

Run a single spec file:

bundle exec rspec spec/pronto/rubycritic_spec.rb

Generate a coverage report (opens coverage/index.html):

COVERAGE=1 bundle exec rspec

Debug the runner against a real project:

cd /path/to/your/project
PRONTO_RUBYCRITIC_DEBUG=1 bundle exec pronto run -r rubycritic --unstaged

Troubleshooting

Symptom	Cause	Fix
no messages reported, but smells exist	You set the now-removed reek.min_severity key	Remove it from .rubycritic-pronto.yml; see migration
undefined method new_file? for Pronto::Git::Patch	Running a test that was written against ≤ 0.11.x mocks	Upgrade test mocks to use instance_double(Pronto::Git::Patch)
invalid YAML in .rubycritic-pronto.yml on stderr, no messages	Config file has a syntax error	Run yamllint .rubycritic-pronto.yml or check your editor's linter
pronto-rubycritic: PRONTO_REEK_SEVERITY_LEVEL is deprecated…	Legacy env var still set	Switch to PRONTO_RUBYCRITIC_SEVERITY_LEVEL
All smells reported as :warning regardless of config	Default severity is :warning in 0.12.0	Set severity_level: info in .pronto.yml under rubycritic:
RubyCritic::SourceControlSystem::NotFoundError in CI	Working dir is not a git repo	Ensure actions/checkout@v4 uses fetch-depth: 0

Set PRONTO_RUBYCRITIC_DEBUG=1 for the first 10 lines of any backtrace.

Migrating from 0.11.x

Change	Action needed
reek.min_severity removed	Delete the key from .rubycritic-pronto.yml. It was dead code that silently filtered out every smell.
flay.max_score / flog.max_score now actually filter	Expect more accurate filtering — previously these keys were no-ops.
Default severity :info → :warning	To keep :info, set PRONTO_RUBYCRITIC_SEVERITY_LEVEL=info or add rubycritic.severity_level: info to .pronto.yml.
PRONTO_REEK_SEVERITY_LEVEL deprecated	Rename to PRONTO_RUBYCRITIC_SEVERITY_LEVEL. The legacy var still works with a deprecation warning.
Pronto::RubyCritic::VERSION added	Existing Pronto::RubyCriticVersion::VERSION still works.
rubycritic dependency now pinned < 6.0	If you pin RubyCritic 6.x in your own Gemfile, wait for pronto-rubycritic 0.13.

Full breaking-change rationale in CHANGELOG.md.

Contributing

1. Fork the repo
2. Create a feature branch (git checkout -b feature/amazing-thing)
3. Make your changes with tests
4. Run the full CI suite locally: bundle exec rake ci
5. Open a PR

See CONTRIBUTING.md for more detail. All contributions must pass RuboCop, Reek, RSpec with ≥ 90 % line coverage, and RubyCritic ≥ 75 score.

License

MIT © Rishabh Singh. See LICENSE for the full text.