Pass fallback_diff_refs to Diff::File instead of using view helpers

5 files changed, 28 insertions, 40 deletions

diff --git a/app/models/concerns/note_on_diff.rb b/app/models/concerns/note_on_diff.rb
index 6359f7596b1..f734952fa6c 100644
--- a/app/models/concerns/note_on_diff.rb
+++ b/app/models/concerns/note_on_diff.rb
@@ -33,14 +33,4 @@ module NoteOnDiff
   def created_at_diff?(diff_refs)
     false
   end
-
-  private
-
-  def noteable_diff_refs
-    if noteable.respond_to?(:diff_sha_refs)
-      noteable.diff_sha_refs
-    else
-      noteable.diff_refs
-    end
-  end
 end
diff --git a/app/models/diff_note.rb b/app/models/diff_note.rb
index 76c59199afd..c6b770a180f 100644
--- a/app/models/diff_note.rb
+++ b/app/models/diff_note.rb
@@ -60,7 +60,7 @@ class DiffNote < Note
     return false unless supported?
     return true if for_commit?
 
-    diff_refs ||= noteable_diff_refs
+    diff_refs ||= noteable.diff_refs
 
     self.position.diff_refs == diff_refs
   end
@@ -96,7 +96,7 @@ class DiffNote < Note
       self.project,
       nil,
       old_diff_refs: self.position.diff_refs,
-      new_diff_refs: noteable_diff_refs,
+      new_diff_refs: noteable.diff_refs,
       paths: self.position.paths
     ).execute(self)
   end
diff --git a/app/models/legacy_diff_note.rb b/app/models/legacy_diff_note.rb
index d7c627432d2..ebf8fb92ab5 100644
--- a/app/models/legacy_diff_note.rb
+++ b/app/models/legacy_diff_note.rb
@@ -61,7 +61,7 @@ class LegacyDiffNote < Note
     return true if for_commit?
     return true unless diff_line
     return false unless noteable
-    return false if diff_refs && diff_refs != noteable_diff_refs
+    return false if diff_refs && diff_refs != noteable.diff_refs
 
     noteable_diff = find_noteable_diff
 
diff --git a/app/models/merge_request.rb b/app/models/merge_request.rb
index 9be00880438..08c72edc728 100644
--- a/app/models/merge_request.rb
+++ b/app/models/merge_request.rb
@@ -245,19 +245,6 @@ class MergeRequest < ActiveRecord::Base
     end
   end
 
-  # MRs created before 8.4 don't store a MergeRequestDiff#base_commit_sha,
-  # but we need to get a commit for the "View file @ ..." link by deleted files,
-  # so we find the likely one if we can't get the actual one.
-  # This will not be the actual base commit if the target branch was merged into
-  # the source branch after the merge request was created, but it is good enough
-  # for the specific purpose of linking to a commit.
-  # It is not good enough for use in `Gitlab::Git::DiffRefs`, which needs the
-  # true base commit, so we can't simply have `#diff_base_commit` fall back on
-  # this method.
-  def likely_diff_base_commit
-    first_commit.try(:parent) || first_commit
-  end
-
   def diff_start_commit
     if persisted?
       merge_request_diff.start_commit
@@ -322,21 +309,14 @@ class MergeRequest < ActiveRecord::Base
   end
 
   def diff_refs
-    return unless diff_start_commit || diff_base_commit
-
-    Gitlab::Diff::DiffRefs.new(
-      base_sha:  diff_base_sha,
-      start_sha: diff_start_sha,
-      head_sha:  diff_head_sha
-    )
-  end
-
-  # Return diff_refs instance trying to not touch the git repository
-  def diff_sha_refs
-    if merge_request_diff && merge_request_diff.diff_refs_by_sha?
+    if persisted?
       merge_request_diff.diff_refs
     else
-      diff_refs
+      Gitlab::Diff::DiffRefs.new(
+        base_sha:  diff_base_sha,
+        start_sha: diff_start_sha,
+        head_sha:  diff_head_sha
+      )
     end
   end
 
@@ -858,7 +838,7 @@ class MergeRequest < ActiveRecord::Base
   end
 
   def has_complete_diff_refs?
-    diff_sha_refs && diff_sha_refs.complete?
+    diff_refs && diff_refs.complete?
   end
 
   def update_diff_notes_positions(old_diff_refs:, new_diff_refs:)
diff --git a/app/models/merge_request_diff.rb b/app/models/merge_request_diff.rb
index f0a3c30ea74..a6f3994166b 100644
--- a/app/models/merge_request_diff.rb
+++ b/app/models/merge_request_diff.rb
@@ -150,6 +150,24 @@ class MergeRequestDiff < ActiveRecord::Base
     )
   end
 
+  # MRs created before 8.4 don't store their true diff refs (start and base),
+  # but we need to get a commit SHA for the "View file @ ..." link by a file,
+  # so we find use an approximation of the diff refs if we can't get the actual one.
+  # These will not be the actual diff refs if the target branch was merged into
+  # the source branch after the merge request was created, but it is good enough
+  # for the specific purpose of linking to a commit.
+  # It is not good enough for highlighting diffs, so we can't simply pass
+  # these as `diff_refs.`
+  def fallback_diff_refs
+    likely_base_commit_sha = (first_commit&.parent || first_commit)&.sha
+
+    Gitlab::Diff::DiffRefs.new(
+      base_sha:  likely_base_commit_sha,
+      start_sha: safe_start_commit_sha,
+      head_sha:  head_commit_sha
+    )
+  end
+
   def diff_refs_by_sha?
     base_commit_sha? && head_commit_sha? && start_commit_sha?
   end