Merge branch 'diff-parse-first-commit' into 'master'

Properly generate diff of orphan commits, like the first commit in a
repository

Fixes gitlab-org/gitlab_git#14

See merge request !2427

2 files changed, 4 insertions, 2 deletions

diff --git a/CHANGELOG b/CHANGELOG
index d613249356b..8d00d890f8e 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -5,6 +5,7 @@ v 8.5.0 (unreleased)
 
 v 8.4.0 (unreleased)
   - Add pagination headers to already paginated API resources
+  - Properly generate diff of orphan commits, like the first commit in a repository
   - Improve the consistency of commit titles, branch names, tag names, issue/MR titles, on their respective project pages
   - Autocomplete data is now always loaded, instead of when focusing a comment text area (Yorick Peterse)
   - Improved performance of finding issues for an entire group (Yorick Peterse)
diff --git a/lib/gitlab/diff/parser.rb b/lib/gitlab/diff/parser.rb
index 7015fe36c3d..516e59b87a3 100644
--- a/lib/gitlab/diff/parser.rb
+++ b/lib/gitlab/diff/parser.rb
@@ -56,8 +56,9 @@ module Gitlab
       private
 
       def filename?(line)
-        line.start_with?('--- /dev/null', '+++ /dev/null', '--- a', '+++ b',
-                         '--- /tmp/diffy', '+++ /tmp/diffy')
+        line.start_with?( '--- /dev/null', '+++ /dev/null', '--- a', '+++ b',
+                          '+++ a', # The line will start with `+++ a` in the reverse diff of an orphan commit
+                          '--- /tmp/diffy', '+++ /tmp/diffy')
       end
 
       def identification_type(line)