Add a --cache option and fix CI

.github/workflows/test.yml

@@ -0,0 +1,50 @@
+name: gha-workflow-libyear-bundler-test
+on: [push, pull_request]
+jobs:
+
+  # Linting is a separate job, primary because it only needs to be done once,
+  # and secondarily because jobs are performed concurrently.
+  gha-job-pt-lint:
+    name: Lint
+    runs-on: ubuntu-18.04
+    steps:
+      - name: Checkout source
+        uses: actions/checkout@v2
+      - name: Setup ruby
+        uses: ruby/setup-ruby@v1
+        with:
+          # Lowest supported ruby version. See gemspec
+          ruby-version: '2.1'
+      - name: Bundle
+        run: |
+          bundle install --jobs 4 --retry 3
+      - name: Lint
+        run: bundle exec rubocop
+  gha-job-pt-test:
+    name: Ruby ${{ matrix.ruby }}
+    runs-on: ubuntu-18.04
+    strategy:
+      # Currently a one-dimensional matrix of ruby versions. In the future we
+      # add bundler version as the second dimension.
+      matrix:
+        # See lowest supported ruby version in gemspec
+        ruby:
+          - '2.1'
+          - '2.2'
+          - '2.3'
+          - '2.4'
+          - '2.5'
+          - '2.6'
+          - '2.7'
+          - '3.0'
+    steps:
+      - name: Checkout source
+        uses: actions/checkout@v2
+      - name: Setup ruby
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: ${{ matrix.ruby }}
+      - name: Bundle
+        run: bundle install --jobs 4 --retry 3
+      - name: Test
+        run: bundle exec rspec

.gitignore

@@ -8,3 +8,5 @@
 /spec/reports/
 /tmp/
 .ruby-version
+.idea
+.byebug_history

.rubocop.yml

@@ -12,14 +12,25 @@ Layout/MultilineMethodCallIndentation:
 Metrics/AbcSize:
   Max: 27
 
+# Not a useful metric compared to, e.g. `AbcSize`.
 Metrics/BlockLength:
-  Exclude:
-    - 'spec/**/*'
+  Enabled: false
+
+# Please use semantic style, e.g. `do` when there's a side-effect, else `{}`.
+# The semantic style is too nuanced to lint, so the cop is disabled.
+Style/BlockDelimiters:
+  Enabled: false
 
 # Annotated tokens harm readability in 90% of format strings.
 Style/FormatStringToken:
   Enabled: false
 
+# The decision of when to use a guard clause to improve readability is subtle,
+# and it's not clear that it can be linted. Certainly, the default
+# `MinBodyLength` of 1 can actually hurt readability.
+Style/GuardClause:
+  Enabled: false
+
 # Too subtle to lint. Prefer normal conditionals, except on very simple lines.
 Style/IfUnlessModifier:
   Enabled: false
@@ -36,4 +47,3 @@ Metrics/MethodLength:
 
 Style/StringLiterals:
   Enabled: false
-

CONTRIBUTING.md

@@ -4,9 +4,29 @@
 
 Pull requests are welcome.
 
+## Support for old rubies
+
+We test all minor versions of ruby, back to 2.1. It's important that people with
+badly out-of-date systems can still measure how bad they are.
+
+### Installing old rubies
+
+> When building Ruby 2.3 or older, [use] OpenSSL 1.0 ..
+> https://github.com/rbenv/ruby-build/wiki#openssl-version-compatibility
+
+```bash
+brew install rbenv/tap/openssl@1.0
+RUBY_CONFIGURE_OPTS="--with-openssl-dir=$(brew --prefix openssl@1.0)" \
+  rbenv install 2.1.10
+```
+
+## Test
+
 ```bash
+rbenv shell 2.1.10 # See installing, above
 bundle install
-bin/test
+bundle exec rubocop
+bundle exec rspec
 ```
 
 ## Releases

bin/run

@@ -3,4 +3,4 @@
 # Used only by the maintainers of libyear_bundler, this file is a convenient
 # way to run during local development.
 
-ruby -I lib -r libyear_bundler -e 'LibyearBundler::CLI.new(ARGV).run'
+ruby -I lib -r libyear_bundler -e 'LibyearBundler::CLI.new(ARGV).run' -- $@

lib/libyear_bundler/bundle_outdated.rb

@@ -11,8 +11,9 @@ class BundleOutdated
     # Format of `bundle outdated --parseable` (BOP)
     BOP_FMT = /\A(?<name>[^ ]+) \(newest (?<newest>[^,]+), installed (?<installed>[^,)]+)/
 
-    def initialize(gemfile_path)
+    def initialize(gemfile_path, release_date_cache)
       @gemfile_path = gemfile_path
+      @release_date_cache = release_date_cache
     end
 
     def execute
@@ -27,7 +28,8 @@ def execute
         gem = ::LibyearBundler::Models::Gem.new(
           match['name'],
           match['installed'],
-          match['newest']
+          match['newest'],
+          @release_date_cache
         )
         gems.push(gem)
       end

lib/libyear_bundler/cli.rb

@@ -2,6 +2,7 @@
 require "bundler/cli/outdated"
 require "libyear_bundler/bundle_outdated"
 require "libyear_bundler/options"
+require "libyear_bundler/release_date_cache"
 require "libyear_bundler/report"
 require 'libyear_bundler/models/ruby'
 
@@ -27,6 +28,12 @@ def run
       else
         print report.to_s
       end
+
+      # Update cache
+      cache_path = @options.cache_path
+      if cache_path && release_date_cache
+        release_date_cache.save(cache_path)
+      end
     end
 
     private
@@ -54,7 +61,15 @@ def load_gemfile_path
     end
 
     def bundle_outdated
-      BundleOutdated.new(@gemfile_path).execute
+      BundleOutdated.new(@gemfile_path, release_date_cache).execute
+    end
+
+    def release_date_cache
+      @_release_date_cache ||= begin
+        path = @options.cache_path
+        return if path.nil?
+        ReleaseDateCache.load(path)
+      end
     end
 
     def report
@@ -63,7 +78,7 @@ def report
 
     def ruby
       lockfile = @gemfile_path + '.lock'
-      ::LibyearBundler::Models::Ruby.new(lockfile)
+      ::LibyearBundler::Models::Ruby.new(lockfile, release_date_cache)
     end
 
     def grand_total

lib/libyear_bundler/models/gem.rb

@@ -7,18 +7,51 @@ module Models
     # Logic and information pertaining to the installed and newest versions of
     # a gem
     class Gem
-      def initialize(name, installed_version, newest_version)
+      def initialize(name, installed_version, newest_version, release_date_cache)
+        unless release_date_cache.nil? || release_date_cache.is_a?(ReleaseDateCache)
+          raise TypeError, 'Invalid release_date_cache'
+        end
         @name = name
         @installed_version = installed_version
         @newest_version = newest_version
+        @release_date_cache = release_date_cache
+      end
+
+      class << self
+        def release_date(gem_name, gem_version)
+          dep = nil
+          begin
+            dep = ::Bundler::Dependency.new(gem_name, gem_version)
+          rescue ::Gem::Requirement::BadRequirementError => e
+            $stderr.puts "Could not find release date for: #{gem_name}"
+            $stderr.puts(e)
+            $stderr.puts(
+              "Maybe you used git in your Gemfile, which libyear doesn't support " \
+              "yet. Contributions welcome."
+            )
+            return nil
+          end
+          tuples, _errors = ::Gem::SpecFetcher.fetcher.search_for_dependency(dep)
+          if tuples.empty?
+            $stderr.puts "Could not find release date for: #{gem_name}"
+            return nil
+          end
+          tup, source = tuples.first # Gem::NameTuple
+          spec = source.fetch_spec(tup) # raises Gem::RemoteFetcher::FetchError
+          spec.date.to_date
+        end
       end
 
       def installed_version
         ::Gem::Version.new(@installed_version)
       end
 
       def installed_version_release_date
-        release_date(name, installed_version)
+        if @release_date_cache.nil?
+          self.class.release_date(name, installed_version)
+        else
+          @release_date_cache[name, installed_version]
+        end
       end
 
       def installed_version_sequence_index
@@ -45,7 +78,11 @@ def newest_version_sequence_index
       end
 
       def newest_version_release_date
-        release_date(name, newest_version)
+        if @release_date_cache.nil?
+          self.class.release_date(name, newest_version)
+        else
+          @release_date_cache[name, newest_version]
+        end
       end
 
       def version_number_delta
@@ -74,31 +111,6 @@ def versions_sequence
           parsed_response.map { |version| version['number'] }
         end
       end
-
-      # Known issue: Probably performs a network request every time, unless
-      # there's some kind of caching.
-      def release_date(gem_name, gem_version)
-        dep = nil
-        begin
-          dep = ::Bundler::Dependency.new(gem_name, gem_version)
-        rescue ::Gem::Requirement::BadRequirementError => e
-          $stderr.puts "Could not find release date for: #{gem_name}"
-          $stderr.puts(e)
-          $stderr.puts(
-            "Maybe you used git in your Gemfile, which libyear doesn't support " \
-              "yet. Contributions welcome."
-          )
-          return nil
-        end
-        tuples, _errors = ::Gem::SpecFetcher.fetcher.search_for_dependency(dep)
-        if tuples.empty?
-          $stderr.puts "Could not find release date for: #{gem_name}"
-          return nil
-        end
-        tup, source = tuples.first # Gem::NameTuple
-        spec = source.fetch_spec(tup) # raises Gem::RemoteFetcher::FetchError
-        spec.date.to_date
-      end
     end
   end
 end