Liquid Exception: stack level too deep - on old commits of the blog too, but works without excerpt_separator in _config.yml

Help
1

I pushed a new post to GithubPages, and it did not show up on the website. Trying to rerun it locally shows the “Liquid Exception: stack level too deep” exception. Trying to run jekyll on any of the old commits runs into the same error. I tried to run bundle update. And got jekyll version 4.4.1 instead of 4.3.2 previously. Not sure if that matters.

I run jekyll locally like this:

bundle exec jekyll serve --livereload --trace

It looks like if I comment out

excerpt_separator: <!--more-->

in _config.yml then it does work fine. Although, it prints many deprecation warnings for Dart Sass 3.0.0.

So, there was some update in the excerpt_separator option? Is that it?

The versions:

$ ruby --version
ruby 3.4.7 (2025-10-08 revision 7a5688e2a2) +PRISM [x86_64-linux]
$ bundle --version
Bundler version 2.7.2
$ bundle exec jekyll --version
/home/alex/.gem/gems/jekyll-4.4.1/lib/jekyll.rb:26: warning: logger was loaded from the standard library, but will no longer be part of the default gems starting from Ruby 3.5.0.
You can add logger to your Gemfile or gemspec to silence this warning.
jekyll 4.4.1

The log is:

$ bundle exec jekyll serve --livereload --trace
/home/alex/.gem/gems/jekyll-4.4.1/lib/jekyll.rb:26: warning: logger was loaded from the standard library, but will no longer be part of the default gems starting from Ruby 3.5.0.
You can add logger to your Gemfile or gemspec to silence this warning.
Configuration file: /home/alex/Documents/xealits.github.io/_config.yml
            Source: /home/alex/Documents/xealits.github.io
       Destination: /home/alex/Documents/xealits.github.io/_site
 Incremental build: disabled. Enable with --incremental
      Generating... 
       Jekyll Feed: Generating feed for posts
  Liquid Exception: stack level too deep in index.html/#excerpt
  Liquid Exception: stack level too deep in index.html/#excerpt
...
  Liquid Exception: stack level too deep in index.html/#excerpt
  Liquid Exception: stack level too deep in /home/alex/Documents/xealits.github.io/_layouts/default.html
/home/alex/.gem/gems/liquid-4.0.4/lib/liquid/context.rb:197:in 'Liquid::Context#lookup_and_evaluate': stack level too deep (SystemStackError)
	from /home/alex/.gem/gems/liquid-4.0.4/lib/liquid/variable_lookup.rb:48:in 'block in Liquid::VariableLookup#evaluate'
	from /home/alex/.gem/gems/liquid-4.0.4/lib/liquid/variable_lookup.rb:38:in 'Array#each_index'
	from /home/alex/.gem/gems/liquid-4.0.4/lib/liquid/variable_lookup.rb:38:in 'Liquid::VariableLookup#evaluate'
	from /home/alex/.gem/gems/liquid-4.0.4/lib/liquid/context.rb:159:in 'Liquid::Context#evaluate'
	from /home/alex/.gem/gems/liquid-4.0.4/lib/liquid/variable.rb:82:in 'Liquid::Variable#render'
	from /home/alex/.gem/gems/liquid-4.0.4/lib/liquid/block_body.rb:103:in 'Liquid::BlockBody#render_node_to_output'
	from /home/alex/.gem/gems/liquid-4.0.4/lib/liquid/block_body.rb:80:in 'Liquid::BlockBody#render'
	from /home/alex/.gem/gems/liquid-4.0.4/lib/liquid/tags/for.rb:160:in 'block (2 levels) in Liquid::For#render_segment'
	 ... 10068 levels...
	from /home/alex/.gem/gems/mercenary-0.4.0/lib/mercenary.rb:21:in 'Mercenary.program'
	from /home/alex/.gem/gems/jekyll-4.4.1/exe/jekyll:15:in '<top (required)>'
	from /home/alex/.gem/bin/jekyll:25:in 'Kernel#load'
	from /home/alex/.gem/bin/jekyll:25:in '<main>'

Does it mean that it fails right after “Jekyll Feed: Generating feed for posts” - in the generation of the RSS feed?

I tried to comment out the excerpt in index.html, it did not help.

2

what is in your index page? have you tried commenting out stuff there? is there an excerpt there?