Changelog

All notable changes to this project will be documented in this file.

The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.

Unreleased

YARD documentation on all public classes and methods
CONTRIBUTING.md with development setup, architecture overview, and PR requirements
SECURITY.md with vulnerability reporting instructions
API stability guarantee: semver contract begins at 1.0.0
.yardopts configuration and yard development dependency
documentation_uri in gemspec metadata
gh auth token as automatic token source for developers with GitHub CLI installed

rubocop-rspec plugin for spec linting with targeted cop overrides
VCR integration tests with recorded cassettes for rails, nokogiri, puma, and edge cases
Integration formatter tests verifying text, JSON, and markdown output against real API data
Complete RBS type signatures for all private methods in GithubClient, UriResolver, and CLI
ExitCode module with SUCCESS (0), ERROR (1), and PARTIAL_FAILURE (2) constants
check exits with status based on report errors (0 = all ok, 1 = all failed, 2 = partial)
show exits 0 on success, 1 on error
README: exit codes section, concurrency flag docs, CI integration guide

UriResolver class for source URI resolution with non-GitHub host detection
Informative skip messages for gems hosted on GitLab, Codeberg, Bitbucket, and SourceHut
Automatic redirect following for renamed GitHub repositories (up to 3 hops)
RepoNotFoundError raised with descriptive messages for non-GitHub gems
TagMatcher class for tag format normalization (v1.2.3, 1.2.3, gem_name-1.2.3, release-1.2.3)
GitHub API pagination for gems with 100+ releases (up to 1000 releases)
Early termination when paginated releases pass the current version
Per-request timeout (10s default) and total timeout (120s default)
--timeout flag to set per-request timeout
request_timeout and total_timeout config file options
Interactive mode help hint: "(Space to select, Enter to confirm)"
JSON::ParserError handling in gem report builder to prevent worker thread crashes
Wider network error handling: Errno::ETIMEDOUT, Errno::ECONNRESET, OpenSSL::SSL::SSLError

RubygemsClient delegates URI resolution to UriResolver (extracted extract_github_repo)
Error message for missing repo changed from "Could not find GitHub repository" to "Could not determine source repository"
GithubClient uses TagMatcher for version extraction (replaced TAG_VERSION_REGEX)
GithubClient fetches 100 releases per page (was 30) with pagination support
GithubClient returns empty array for HTTP 301 responses (redirects handled by UriResolver)
All Gem::Version.new calls wrapped in safe_gem_version helper to prevent ArgumentError crashes
ConcurrentFetcher wrapped in total timeout to prevent runaway operations
HTTP requests in Cache, RubygemsClient, and ChangelogParser use configurable timeouts

YAML config file support: .gem_changelog_diff.yml (project) and ~/.config/gem_changelog_diff/config.yml (user)
Supported config keys: github_token, default_format, cache_ttl, concurrency, ignore_gems, no_color
init subcommand: generate a commented config file template
Config file token used as fallback when --token and GITHUB_TOKEN are not set
--dry-run flag: show which gems would be checked without fetching changelogs
Dry-run output respects --format flag (text, JSON, markdown)
Rails credentials token support: reads from Rails.application.credentials.dig(:gem_changelog_diff, :github_token) when running inside a Rails app
Token priority: --token flag → GITHUB_TOKEN env → Rails credentials → config file

Formatter class hierarchy: Formatters::Text, Formatters::Json, Formatters::Markdown
--format flag: text (default), json, or markdown
JSON output (--format json) for piping to jq or CI tools
Markdown output (--format markdown) for PR descriptions
--output flag to write formatted output to a file
Interactive gem selection via tty-prompt (--interactive / -i flag)
show subcommand: gem_changelog_diff show rails 7.0.0 7.1.0

Disk cache at ~/.cache/gem_changelog_diff/ with configurable TTL (default 24h)
ETag conditional requests to avoid consuming rate limit on revalidation
cache clear subcommand
--no-cache and --cache-ttl flags
Concurrent fetching via thread pool (default 4, configurable via --concurrency)
Progress indicator via tty-spinner when running in a terminal

Gemfile.lock parsing via Bundler::LockfileParser with RubyGems API version lookup
Automatic fallback to lockfile parsing when bundle outdated is unavailable
--strategy flag: auto (default), outdated, or lockfile
--lockfile flag for custom lockfile path
Positional arguments to inspect specific gems: gem_changelog_diff check rails sidekiq
--group flag to filter by Bundler group
--ignore flag to exclude specific gems

CHANGELOG.md fallback: fetches and parses changelog files when GitHub Releases are unavailable
Tries common filename variants: CHANGELOG.md, CHANGES.md, History.md, NEWS.md
SourceResolver orchestrates releases-first, changelog-fallback strategy
Colorized terminal output via tty-color; respects $NO_COLOR and --no-color flag
Summary line: "X gems outdated, Y with changelogs found, Z skipped"

GitHub personal access token support via --token flag or GITHUB_TOKEN env var
Configuration singleton for managing runtime settings
Custom error hierarchy: RepoNotFoundError, GitHubAPIError, RateLimitError, NetworkError
Graceful degradation: failed gems are skipped with a warning instead of aborting
Rate limit awareness: warns when GitHub API requests remaining drops below 10
--verbose flag for detailed status output
--quiet flag to suppress warnings

CLI entry point via Thor (exe/gem_changelog_diff) with check default command and version command
Outdated gem detection by parsing bundle outdated --parseable
OutdatedGem data object for representing outdated gem info
RubyGems API client to look up each gem's GitHub repository
GitHub API client to fetch releases between locked and latest versions
Plain text formatter for changelog output
Full end-to-end pipeline: detect → lookup → fetch → format