Commit history page timeout on main branch due to markdown link processing

Problem

Loading the commit history on the main branch results in a 500 error. The issue is specific to one project and the main ref.

From the logs we can see several occurrences of this in the past 30 days: https://log.gprd.gitlab.net/app/r/s/SVUYq

Root Cause

The Projects::CommitsController#show action times out after 60 seconds. The majority of processing time is spent on markdown link processing during commit description rendering.

The error occurs in the markdown rendering pipeline:

• lib/banzai/filter/autolink_filter.rb - autolink filter processing
• lib/gitlab/string_range_marker.rb - string range marking for links
• The timeout happens while processing commit descriptions with markdown links

Error Details

• Exception: Rack::Timeout::RequestTimeoutException
• Duration: Request ran for longer than 60000ms
• CPU Time: ~59.23 seconds spent on markdown processing
• Controller: Projects::CommitsController#show
• Action: Rendering commits for display

Stack Trace Key Points

The timeout occurs during:

1. set_commits_for_rendering - preparing commits for display
2. prepare_commits_for_rendering - rendering commit descriptions
3. Banzai::CommitRenderer#render - processing markdown in commit messages
4. Banzai::ObjectRenderer#render_documents - rendering multiple commits
5. autolink_filter - processing markdown links in descriptions

Workaround

Users can view commits using time range filters with committed_before and committed_after URL parameters to reduce the number of commits being processed.

Related Issues

• Issue #552072 (closed)
• Issue #515892 (closed)

Impact

• Affects commit history viewing on the main branch
• 500 error prevents users from accessing commit history