Increase the soft limits for a merge request

Issue: gitlab.com/gitlab-org/gitlab/-/issues/219565
Merge Request: gitlab.com/gitlab-org/gitlab/-/merge_requests/43123

app/models/commit.rb

@@ -74,8 +74,8 @@ class Commit
       sha[0..MIN_SHA_LENGTH]
     end
 
-    def diff_safe_lines
-      Gitlab::Git::DiffCollection.default_limits[:max_lines]
+    def diff_safe_lines(project: nil)
+      Gitlab::Git::DiffCollection.default_limits(project: project)[:max_lines]
     end
 
     def diff_hard_limit_files(project: nil)

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

-- too_big = diff_file.diff_lines.count > Commit.diff_safe_lines
+- too_big = diff_file.diff_lines.count > Commit.diff_safe_lines(project: @project)
 - if too_big
   .suppressed-container
     %a.show-suppressed-diff.cursor-pointer.js-show-suppressed-diff= _("Changes suppressed. Click to show.")

lib/gitlab/diff/file_collection/merge_request_diff_base.rb

@@ -66,7 +66,9 @@ module Gitlab
         end
 
         def merged_diff_options(diff_options)
-          max_diff_options = ::Commit.max_diff_options(project: @merge_request_diff.project)
+          project = @merge_request_diff.project
+          max_diff_options = ::Commit.max_diff_options(project: project).merge(project: project)
+
           diff_options.present? ? diff_options.merge(max_diff_options) : max_diff_options
         end
       end

lib/gitlab/git/diff_collection.rb

@@ -11,13 +11,17 @@ module Gitlab
 
       delegate :max_files, :max_lines, :max_bytes, :safe_max_files, :safe_max_lines, :safe_max_bytes, to: :limits
 
-      def self.default_limits
+      def self.default_limits(project: nil)
+        if Feature.enabled?(:increased_diff_limits, project)
+          { max_files: 200, max_lines: 7500 }
+        else
           { max_files: 100, max_lines: 5000 }
         end
+      end
 
       def self.limits(options = {})
         limits = {}
-        defaults = default_limits
+        defaults = default_limits(project: options[:project])
         limits[:max_files] = options.fetch(:max_files, defaults[:max_files])
         limits[:max_lines] = options.fetch(:max_lines, defaults[:max_lines])
         limits[:max_bytes] = limits[:max_files] * 5.kilobytes # Average 5 KB per file