fixing diffs to work in the right direction

Author: beatmadsen

bin/files_in_my_diff

@@ -0,0 +1,20 @@
+#!/usr/bin/env ruby
+# frozen_string_literal: true
+
+require 'bundler/setup'
+
+require 'setup_git'
+require 'files_in_my_diff'
+
+require 'json'
+
+folder = ARGV[0]
+revision = ARGV[1]
+
+begin
+  decorated = FilesInMyDiff.checkout(folder:, revision:)
+  puts decorated.to_json
+rescue FilesInMyDiff::Error => e
+  puts e.message
+  exit 1
+end

lib/files_in_my_diff/git/diff.rb

@@ -17,7 +17,10 @@ def sha
       end
 
       def changes
-        @object.diff_parent.map do |change|
+        parent = @object.parents.first
+        return [] if parent.nil?
+
+        parent.diff(@object).map do |change|
           { path: change.path, type: change.type }
         end
       end

lib/files_in_my_diff/resolver.rb

@@ -2,7 +2,7 @@
 
 module FilesInMyDiff
   class Resolver
-    def initialize(folder:, revision:, file_strategy: TmpDir::FileStrategy, git_strategy: Git::Adapter.new(folder:))
+    def initialize(folder:, revision:, file_strategy: TmpDir::FileStrategy, git_strategy: nil)
       @folder = folder
       @revision = revision
       @file_strategy = file_strategy
@@ -11,19 +11,23 @@ def initialize(folder:, revision:, file_strategy: TmpDir::FileStrategy, git_stra
 
     def call
       validate_folder!
-      diff = @git_strategy.diff(@revision)
+      diff = git_strategy.diff(@revision)
       diff.validate!
       rd = @file_strategy.revision_dir(diff.sha)
       rd.create!
-      @git_strategy.checkout_worktree(rd.dir, diff.sha)
+      git_strategy.checkout_worktree(rd.dir, diff.sha)
       rd.decorate(diff.changes)
     end
 
     private
 
     def validate_folder!
       raise ValidationError, 'Folder is required' if @folder.nil?
-      raise ValidationError, 'Folder does not exist' unless @file_strategy.dir_exists?(@folder)
+      raise ValidationError, "Folder '#{@folder}' does not exist" unless @file_strategy.dir_exists?(@folder)
+    end
+
+    def git_strategy
+      @git_strategy ||= Git::Adapter.new(folder: @folder)
     end
   end
 end

test/files_in_my_diff/git/diff_test.rb

@@ -42,9 +42,13 @@ def initialize(diff_success)
 
         def sha = 'x'
 
-        def diff_parent
+        def diff(_other)
           @diff_success ? [Change.new('file_1', :added)] : raise(Git::DiffError)
         end
+
+        def parents
+          [self]
+        end
       end
 
       class Change