Support supressing text file diffs on the default branch with .gitattributes

CHANGELOG

@@ -12,6 +12,7 @@ v 8.8.0 (unreleased)
   - Added button to toggle whitespaces changes on diff view
   - Backport GitLab Enterprise support from EE
   - Files over 5MB can only be viewed in their raw form, files over 1MB without highlighting !3718
+  - Add support for supressing text diffs using .gitattributes on the default branch (Matt Oakes)
 
 v 8.7.1 (unreleased)
   - Throttle the update of `project.last_activity_at` to 1 minute. !3848

Gemfile.lock

@@ -184,7 +184,7 @@ GEM
     encryptor (1.3.0)
     equalizer (0.0.11)
     erubis (2.7.0)
-    escape_utils (1.1.0)
+    escape_utils (1.1.1)
     eventmachine (1.0.8)
     excon (0.45.4)
     execjs (2.6.0)
@@ -334,7 +334,7 @@ GEM
       json
     get_process_mem (0.2.0)
     gherkin-ruby (0.3.2)
-    github-linguist (4.7.5)
+    github-linguist (4.7.6)
       charlock_holmes (~> 0.7.3)
       escape_utils (~> 1.1.0)
       mime-types (>= 1.19)
@@ -351,7 +351,7 @@ GEM
       posix-spawn (~> 0.3)
     gitlab_emoji (0.3.1)
       gemojione (~> 2.2, >= 2.2.1)
-    gitlab_git (10.0.0)
+    gitlab_git (10.0.1)
       activesupport (~> 4.0)
       charlock_holmes (~> 0.7.3)
       github-linguist (~> 4.7.0)

app/models/project.rb

@@ -901,6 +901,7 @@ class Project < ActiveRecord::Base
     repository.rugged.references.create('HEAD',
                                         "refs/heads/#{branch}",
                                         force: true)
+    repository.copy_gitattributes(branch)
     reload_default_branch
   end
 

app/models/repository.rb

@@ -938,6 +938,16 @@ class Repository
     raw_repository.ls_files(actual_ref)
   end
 
+  def copy_gitattributes(ref)
+    actual_ref = ref || root_ref
+    begin
+      raw_repository.copy_gitattributes(actual_ref)
+      true
+    rescue Gitlab::Git::Repository::InvalidRef
+      false
+    end
+  end
+
   def main_language
     return if empty? || rugged.head_unborn?
 

app/services/git_push_service.rb

@@ -42,7 +42,12 @@ class GitPushService < BaseService
       # Collect data for this git push
       @push_commits = @project.repository.commits_between(params[:oldrev], params[:newrev])
       process_commit_messages
+
+      # Update the bare repositories info/attributes file using the contents of the default branches
+      # .gitattributes file
+      update_gitattributes if is_default_branch?
     end
+
     # Update merge requests that may be affected by this push. A new branch
     # could cause the last commit of a merge request to change.
     update_merge_requests
@@ -54,6 +59,10 @@ class GitPushService < BaseService
     perform_housekeeping
   end
 
+  def update_gitattributes
+    @project.repository.copy_gitattributes(params[:ref])
+  end
+
   def update_main_language
     # Performance can be bad so for now only check main_language once
     # See https://gitlab.com/gitlab-org/gitlab-ce/issues/14937

app/views/projects/diffs/_file.html.haml

@@ -40,19 +40,19 @@
         = view_file_btn(diff_commit.id, diff_file, project)
 
   .diff-content.diff-wrap-lines
-    -# Skipp all non non-supported blobs
+    - # Skip all non non-supported blobs
     - return unless blob.respond_to?('text?')
     - if diff_file.too_large?
-      .nothing-here-block
-        This diff could not be displayed because it is too large.
-    - else
-      - if blob_text_viewable?(blob)
-        - if diff_view == 'parallel'
-          = render "projects/diffs/parallel_view", diff_file: diff_file, project: project, blob: blob, index: i
-        - else
-          = render "projects/diffs/text_file", diff_file: diff_file, index: i
-      - elsif blob.image?
-        - old_file = project.repository.prev_blob_for_diff(diff_commit, diff_file)
-        = render "projects/diffs/image", diff_file: diff_file, old_file: old_file, file: blob, index: i, diff_refs: diff_refs
+      .nothing-here-block This diff could not be displayed because it is too large.
+    - elsif blob_text_viewable?(blob) && !project.repository.diffable?(blob)
+      .nothing-here-block This diff was suppressed by a .gitattributes entry.
+    - elsif blob_text_viewable?(blob)
+      - if diff_view == 'parallel'
+        = render "projects/diffs/parallel_view", diff_file: diff_file, project: project, blob: blob, index: i
       - else
-        .nothing-here-block No preview for this file type
+        = render "projects/diffs/text_file", diff_file: diff_file, index: i
+    - elsif blob.image?
+      - old_file = project.repository.prev_blob_for_diff(diff_commit, diff_file)
+      = render "projects/diffs/image", diff_file: diff_file, old_file: old_file, file: blob, index: i, diff_refs: diff_refs
+    - else
+      .nothing-here-block No preview for this file type

spec/models/repository_spec.rb

@@ -795,6 +795,16 @@ describe Repository, models: true do
 
   end
 
+  describe "#copy_gitattributes" do
+    it 'returns true with a valid ref' do
+      expect(repository.copy_gitattributes('master')).to be_truthy
+    end
+
+    it 'returns false with an invalid ref' do
+      expect(repository.copy_gitattributes('invalid')).to be_falsey
+    end
+  end
+
   describe "#main_language" do
     it 'shows the main language of the project' do
       expect(repository.main_language).to eq("Ruby")

spec/services/git_push_service_spec.rb

@@ -201,6 +201,36 @@ describe GitPushService, services: true do
   end
 
 
+  describe "Updates git attributes" do
+    context "for default branch" do
+      it "calls the copy attributes method for the first push to the default branch" do
+        expect(project.repository).to receive(:copy_gitattributes).with('master')
+
+        execute_service(project, user, @blankrev, 'newrev', 'refs/heads/master')
+      end
+
+      it "calls the copy attributes method for changes to the default branch" do
+        expect(project.repository).to receive(:copy_gitattributes).with('refs/heads/master')
+
+        execute_service(project, user, 'oldrev', 'newrev', 'refs/heads/master')
+      end
+    end
+
+    context "for non-default branch" do
+      before do
+        # Make sure the "default" branch is different
+        allow(project).to receive(:default_branch).and_return('not-master')
+      end
+
+      it "does not call copy attributes method" do
+        expect(project.repository).not_to receive(:copy_gitattributes)
+
+        execute_service(project, user, @oldrev, @newrev, @ref)
+      end
+    end
+  end
+
+
   describe "Webhooks" do
     context "execute webhooks" do
       it "when pushing a branch for the first time" do