Revert "Merge branch 'revert-a91ff32b' into 'master'"

This reverts merge request !8688

app/assets/stylesheets/framework/files.scss

@@ -231,3 +231,37 @@ span.idiff {
     }
   }
 }
+
+
+.file-title-flex-parent {
+  display: flex;
+  align-items: center;
+  background-color: $gray-light;
+  border-bottom: 1px solid $border-color;
+  padding: 10px $gl-padding;
+  margin: 0;
+  border-radius: 3px 3px 0 0;
+
+  > a {
+    flex: 1;
+    white-space: nowrap;
+    overflow: hidden;
+    text-overflow: ellipsis;
+    color: $gl-text-color;
+  }
+
+  small {
+    margin: 0 10px 0 0;
+  }
+
+  .file-actions {
+    white-space: nowrap;
+
+    .btn {
+      padding: 0 10px;
+      font-size: 13px;
+      line-height: 28px;
+      display: inline-block;
+    }
+  }
+}

app/assets/stylesheets/pages/diff.scss

@@ -37,6 +37,10 @@
   .file-title {
     cursor: pointer;
 
+    a:hover {
+      text-decoration: none;
+    }
+
     &:hover {
       background-color: $gray-normal;
     }

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

 - environment = local_assigns.fetch(:environment, nil)
 .diff-file.file-holder{ id: file_hash, data: diff_file_html_data(project, diff_file.file_path, diff_commit.id) }
-  .file-title
+  .file-title-flex-parent
     = render "projects/diffs/file_header", diff_file: diff_file, blob: blob, diff_commit: diff_commit, project: project, url: "##{file_hash}"
 
     - unless diff_file.submodule?

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

@@ -10,13 +10,13 @@
 
     - if diff_file.renamed_file
       - old_path, new_path = mark_inline_diffs(diff_file.old_path, diff_file.new_path)
-      %strong
+      %strong.file-title-name.has-tooltip{ data: { title: old_path } }
         = old_path
       →
-      %strong
+      %strong.file-title-name.has-tooltip{ data: { title: new_path } }
         = new_path
     - else
-      %strong
+      %strong.file-title-name.has-tooltip{ data: { title: diff_file.new_path } }
         = diff_file.new_path
       - if diff_file.deleted_file
         deleted

changelogs/unreleased/25709-diff-file-overflow.yml

+---
+title: Responsive title in diffs inline, side by side, with and without sidebar
+merge_request: 8475
+author: