Merge pull request #2 from mattlqx/cookbook-metadata

fall back to master if branch doesn't exist yet

README.md

@@ -15,7 +15,7 @@ To check Chef cookbook version bumps, use the `chef-cookbook-version` hook. Each
 To unit test Ruby changes in your repo, use the `rspec` hook. Each path in your repo with a `spec` directory should have a `Gemfile` that includes your desired version of rspec (or a derivative library). It will be installed via Bundler prior to testing. Rspec will only be run against the closest directory in a changed file's path with a spec dir.
 
     - repo: https://github.com/mattlqx/pre-commit-ruby
-      rev: v1.2.0
+      rev: v1.2.1
       hooks:
       - id: rubocop
       - id: foodcritic

bin/cookbook-wrapper.rb

@@ -39,6 +39,13 @@ def higher?(old_version, new_version)
   end == true
 end
 
+def file_from_git_history(branch, path)
+  prefix = path.start_with?('/') ? '' : './'
+  from_branch = IO.popen("git show origin/#{branch}:#{prefix}#{path}", err: :close, &:read)
+  return from_branch unless from_branch == ''
+  IO.popen("git show origin/master:#{prefix}#{path}", err: :close, &:read)
+end
+
 # Simple metadata.rb reader
 class MetadataReader
   attr_reader :data
@@ -90,14 +97,12 @@ def method_missing(sym, *args, &_block) # rubocop:disable Metrics/AbcSize, Style
 changed_cookbooks.each do |cb_data|
   cookbook = cb_data[0]
   type = cb_data[1]
-  prefix = cookbook.start_with?('/') ? '' : './'
-  git_cmd = "git show origin/#{branch}:#{prefix}#{cookbook}/metadata.#{type}"
 
   if type == 'rb'
-    old_metadata = MetadataReader.new(IO.popen(git_cmd, err: :close, &:read), "#{cookbook}/metadata.rb")
+    old_metadata = MetadataReader.new(file_from_git_history(branch, "#{cookbook}/metadata.rb"), "#{cookbook}/metadata.rb") # rubocop:disable Metrics/LineLength
     new_metadata = MetadataReader.new(IO.read("#{cookbook}/metadata.rb"), "#{cookbook}/metadata.rb")
   else
-    old_metadata = JSON.parse(IO.popen(git_cmd, err: :close, &:read)) rescue {} # rubocop:disable Style/RescueModifier
+    old_metadata = JSON.parse(file_from_git_history(branch, "#{cookbook}/metadata.json")) rescue {} # rubocop:disable Style/RescueModifier, Metrics/LineLength
     new_metadata = JSON.parse(IO.read("#{cookbook}/metadata.json"))
   end