From ba54c407cbad615f468dbb69112b3b536e9198ea Mon Sep 17 00:00:00 2001
From: Sven Weidauer <sven@5sw.de>
Date: Mon, 6 Jun 2022 10:18:05 +0200
Subject: [PATCH] [#1] Fail if all files are reset to committed version.

---
 Gemfile                  |  2 +-
 bin/git-format-staged    |  3 ++-
 lib/format-staged/job.rb | 17 ++++++++++++++---
 spec/test_spec.rb        | 27 +++++++++++++++++++++++----
 4 files changed, 40 insertions(+), 9 deletions(-)

diff --git a/Gemfile b/Gemfile
index b37c960..26ea26a 100644
--- a/Gemfile
+++ b/Gemfile
@@ -6,5 +6,5 @@ gemspec
 
 group :ci do
   gem 'code-scanning-rubocop'
-  gem "rspec_junit_formatter"
+  gem 'rspec_junit_formatter'
 end
diff --git a/bin/git-format-staged b/bin/git-format-staged
index a9454e3..5195cfa 100755
--- a/bin/git-format-staged
+++ b/bin/git-format-staged
@@ -73,4 +73,5 @@ if !parameters[:formatter] || parameters[:patterns].empty?
   exit
 end
 
-FormatStaged.run(**parameters)
+success = FormatStaged.run(**parameters)
+exit success ? 0 : 1
diff --git a/lib/format-staged/job.rb b/lib/format-staged/job.rb
index 4955e3a..6ad0b44 100644
--- a/lib/format-staged/job.rb
+++ b/lib/format-staged/job.rb
@@ -28,9 +28,15 @@ module FormatStaged
     end
 
     def run
-      matching_files(repo_root).each do |file|
-        format_file(file)
+      files = matching_files(repo_root)
+      if files.empty?
+        info 'No staged file matching pattern. Done'
+        return true
       end
+
+      formatted = files.filter { |file| format_file file }
+
+      !formatted.empty?
     end
 
     def repo_root
@@ -57,7 +63,7 @@ module FormatStaged
 
       if new_hash == file.dst_hash
         info "Unchanged #{file.src_path}"
-        return false
+        return true
       end
 
       if object_is_empty new_hash
@@ -68,6 +74,11 @@ module FormatStaged
       replace_file_in_index file, new_hash
       update_working_copy file, new_hash
 
+      if new_hash == file.src_hash
+        info "File #{file.src_path} equal to comitted"
+        return false
+      end
+
       true
     end
 
diff --git a/spec/test_spec.rb b/spec/test_spec.rb
index 2b3ef4c..1c30107 100644
--- a/spec/test_spec.rb
+++ b/spec/test_spec.rb
@@ -19,8 +19,9 @@ describe FormatStaged do
   it 'updates staged file and working copy' do
     repo.set_content 'test.test', 'a=b'
     repo.stage 'test.test'
-    repo.run_formatter
+    success = repo.run_formatter
 
+    expect(success).to be_truthy
     expect(repo.get_staged('test.test')).to eq('a = b')
     expect(repo.get_content('test.test')).to eq('a = b')
   end
@@ -29,8 +30,9 @@ describe FormatStaged do
     repo.set_content 'test.test', "x=y\na=b\n"
     repo.stage 'test.test'
     repo.set_content 'test.test', 'abc'
-    repo.run_formatter
+    success = repo.run_formatter
 
+    expect(success).to be_truthy
     expect(repo.get_content('test.test')).to eq('abc')
     expect(repo.get_staged('test.test')).to eq("x = y\na = b")
   end
@@ -39,8 +41,9 @@ describe FormatStaged do
     repo.set_content 'test.test', "x=y\n#stuff\n"
     repo.stage 'test.test'
     repo.set_content 'test.test', "x=y\n#stuff\nmore stuff\n"
-    repo.run_formatter
+    success = repo.run_formatter
 
+    expect(success).to be_truthy
     expect(repo.get_content('test.test')).to eq("x = y\n#stuff\nmore stuff")
     expect(repo.get_staged('test.test')).to eq("x = y\n#stuff")
   end
@@ -48,8 +51,24 @@ describe FormatStaged do
   it 'only touches files matching the given pattern' do
     repo.set_content 'test.other', 'x=y'
     repo.stage 'test.other'
-    repo.run_formatter
+    success = repo.run_formatter
 
+    expect(success).to be_truthy
     expect(repo.get_content('test.other')).to eq('x=y')
   end
+
+  it 'fails if files are changed to already comitted version' do
+    repo.file_in_tree 'test.test', 'x = y'
+    repo.set_content 'test.test', 'x=y'
+    repo.stage 'test.test'
+
+    success = repo.run_formatter
+
+    expect(success).to be_falsy
+    expect(repo.get_content('test.test')).to eq('x = y')
+  end
+
+  it 'succeeds if there are no staged files' do
+    expect(repo.run_formatter).to be_truthy
+  end
 end