gjtorikian / html-proofer

Running rake throws NoMethodError: undefined method 'empty?' for true:TrueClass.

** Invoke test (first_time)
** Execute test
bundle exec jekyll build
Configuration file: /Users/<redacted>/projects/side/<redacted>/_config.yml
To use retry middleware with Faraday v2.0+, install `faraday-retry` gem
            Source: /Users/<redacted>/projects/side/<redacted>
       Destination: /Users/<redacted>/projects/side/<redacted>/_site
 Incremental build: disabled. Enable with --incremental
      Generating...
       Jekyll Feed: Generating feed for posts
   GitHub Metadata: No GitHub API authentication could be found. Some fields may be missing or have incorrect data.
                    done in 1.078 seconds.
 Auto-regeneration: disabled. Use --watch to enable.
Running 3 checks (Scripts, Links, Images) in ["./_site"] on *.html files...


rake aborted!
NoMethodError: undefined method `empty?' for true:TrueClass
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/gems/html-proofer-4.4.3/lib/html_proofer/utils.rb:12:in `blank?'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/gems/html-proofer-4.4.3/lib/html_proofer/attribute/url.rb:138:in `file_path'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/gems/html-proofer-4.4.3/lib/html_proofer/attribute/url.rb:128:in `absolute_path'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/gems/html-proofer-4.4.3/lib/html_proofer/check/links.rb:57:in `block in run'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/gems/nokogiri-1.13.9-arm64-darwin/lib/nokogiri/xml/node_set.rb:234:in `block in each'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/gems/nokogiri-1.13.9-arm64-darwin/lib/nokogiri/xml/node_set.rb:233:in `upto'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/gems/nokogiri-1.13.9-arm64-darwin/lib/nokogiri/xml/node_set.rb:233:in `each'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/gems/html-proofer-4.4.3/lib/html_proofer/check/links.rb:7:in `run'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/gems/html-proofer-4.4.3/lib/html_proofer/runner.rb:128:in `block in check_parsed'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/gems/html-proofer-4.4.3/lib/html_proofer/runner.rb:119:in `each'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/gems/html-proofer-4.4.3/lib/html_proofer/runner.rb:119:in `check_parsed'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/gems/html-proofer-4.4.3/lib/html_proofer/runner.rb:111:in `load_file'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/gems/html-proofer-4.4.3/lib/html_proofer/runner.rb:101:in `block in process_files'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/gems/parallel-1.22.1/lib/parallel.rb:587:in `call_with_index'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/gems/parallel-1.22.1/lib/parallel.rb:557:in `process_incoming_jobs'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/gems/parallel-1.22.1/lib/parallel.rb:537:in `block in worker'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/gems/parallel-1.22.1/lib/parallel.rb:528:in `fork'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/gems/parallel-1.22.1/lib/parallel.rb:528:in `worker'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/gems/parallel-1.22.1/lib/parallel.rb:519:in `block in create_workers'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/gems/parallel-1.22.1/lib/parallel.rb:518:in `each'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/gems/parallel-1.22.1/lib/parallel.rb:518:in `each_with_index'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/gems/parallel-1.22.1/lib/parallel.rb:518:in `create_workers'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/gems/parallel-1.22.1/lib/parallel.rb:457:in `work_in_processes'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/gems/parallel-1.22.1/lib/parallel.rb:294:in `map'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/gems/html-proofer-4.4.3/lib/html_proofer/runner.rb:101:in `process_files'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/gems/html-proofer-4.4.3/lib/html_proofer/runner.rb:75:in `check_files'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/gems/html-proofer-4.4.3/lib/html_proofer/runner.rb:46:in `run'
/Users/<redacted>/projects/side/<redacted>/Rakefile:20:in `block in <top (required)>'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/gems/rake-13.0.6/lib/rake/task.rb:281:in `block in execute'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/gems/rake-13.0.6/lib/rake/task.rb:281:in `each'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/gems/rake-13.0.6/lib/rake/task.rb:281:in `execute'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/gems/rake-13.0.6/lib/rake/task.rb:219:in `block in invoke_with_call_chain'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/gems/rake-13.0.6/lib/rake/task.rb:199:in `synchronize'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/gems/rake-13.0.6/lib/rake/task.rb:199:in `invoke_with_call_chain'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/gems/rake-13.0.6/lib/rake/task.rb:188:in `invoke'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/gems/rake-13.0.6/lib/rake/application.rb:160:in `invoke_task'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/gems/rake-13.0.6/lib/rake/application.rb:116:in `block (2 levels) in top_level'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/gems/rake-13.0.6/lib/rake/application.rb:116:in `each'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/gems/rake-13.0.6/lib/rake/application.rb:116:in `block in top_level'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/gems/rake-13.0.6/lib/rake/application.rb:125:in `run_with_threads'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/gems/rake-13.0.6/lib/rake/application.rb:110:in `top_level'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/gems/rake-13.0.6/lib/rake/application.rb:83:in `block in run'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/gems/rake-13.0.6/lib/rake/application.rb:186:in `standard_exception_handling'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/gems/rake-13.0.6/lib/rake/application.rb:80:in `run'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/gems/rake-13.0.6/exe/rake:27:in `<top (required)>'
/Users/<redacted>/.rbenv/versions/2.7.3/bin/rake:23:in `load'
/Users/<redacted>/.rbenv/versions/2.7.3/bin/rake:23:in `<top (required)>'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/2.7.0/bundler/cli/exec.rb:63:in `load'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/2.7.0/bundler/cli/exec.rb:63:in `kernel_load'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/2.7.0/bundler/cli/exec.rb:28:in `run'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/2.7.0/bundler/cli.rb:476:in `exec'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/2.7.0/bundler/vendor/thor/lib/thor/command.rb:27:in `run'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/2.7.0/bundler/vendor/thor/lib/thor/invocation.rb:127:in `invoke_command'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/2.7.0/bundler/vendor/thor/lib/thor.rb:399:in `dispatch'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/2.7.0/bundler/cli.rb:30:in `dispatch'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/2.7.0/bundler/vendor/thor/lib/thor/base.rb:476:in `start'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/2.7.0/bundler/cli.rb:24:in `start'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/gems/bundler-2.1.4/libexec/bundle:46:in `block in <top (required)>'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/2.7.0/bundler/friendly_errors.rb:123:in `with_friendly_errors'
/Users/<redacted>/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/gems/bundler-2.1.4/libexec/bundle:34:in `<top (required)>'
/Users/<redacted>/.rbenv/versions/2.7.3/bin/bundle:23:in `load'
/Users/<redacted>/.rbenv/versions/2.7.3/bin/bundle:23:in `<main>'

Gemfile.lock.txt

Chip: Apple M1 Max
macOS: 13.0.1 (22A400)

You're running a rather old version (4.4.3), whereas the latest is 5.0.2. Can you try updating the gem and trying again?

Oh, I didn't notice there was a new version. I think I know why it didn't install the latest version.

I'm using html-proofer with GitHub Actions, and these are the available Ruby versions on there:

available versions for ruby on ubuntu-20.04: 2.0.0-p648, 2.1.9, 2.2.10, 2.3.0, 2.3.1,
2.3.2, 2.3.3, 2.3.4,2.3.5, 2.3.6, 2.3.7, 2.3.8, 2.4.0, 2.4.1, 2.4.2, 2.4.3, 2.4.4, 2.4.5,
2.4.6, 2.4.7, 2.4.9, 2.4.10, 2.5.0, 2.5.1, 2.5.2, 2.5.3, 2.5.4, 2.5.5, 2.5.6, 2.5.7, 2.5.8,
2.5.9, 2.6.0, 2.6.1, 2.6.2, 2.6.3, 2.6.4, 2.6.5, 2.6.6, 2.6.7, 2.7.0, 2.7.1, 2.7.2, 2.7.3,
3.0.0-preview1, 3.0.0-preview2, 3.0.0-rc1, 3.0.0, 3.0.1, head, debug

I have Ruby 3.0.1 installed, and when I run gem install html-proofer -v 5.0.2 the output is

ERROR:  Error installing html-proofer:
	html-proofer-5.0.2 requires Ruby version >= 3.1, < 4.0. The current ruby version is 3.0.1.64.

I updated the Ruby version to 3.1.3, and I got the same error

bundle exec jekyll build
Configuration file: /Users/<redacted>/projects/side/<redacted>/_config.yml
To use retry middleware with Faraday v2.0+, install `faraday-retry` gem
            Source: /Users/<redacted>/projects/side/<redacted>
       Destination: /Users/<redacted>/projects/side/<redacted>/_site
 Incremental build: disabled. Enable with --incremental
      Generating...
       Jekyll Feed: Generating feed for posts
   GitHub Metadata: No GitHub API authentication could be found. Some fields may be missing or have incorrect data.
                    done in 1.206 seconds.
 Auto-regeneration: disabled. Use --watch to enable.
Running 3 checks (Images, Links, Scripts) in ["./_site"] on *.html files ...


  0.0s     warn: Async::Task [oid=0xf78] [ec=0xf8c] [pid=53492] [2022-11-25 10:32:53 +0100]
               | Task may have ended with unhandled exception.
               |   NoMethodError: undefined method `empty?' for true:TrueClass
               |
               |         obj.nil? || obj.empty?
               |                        ^^^^^^^
               |   → /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/utils.rb:12 in `blank?'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/attribute/url.rb:138 in `file_path'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/attribute/url.rb:128 in `absolute_path'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/check/links.rb:57 in `block in run'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/nokogiri-1.13.9-arm64-darwin/lib/nokogiri/xml/node_set.rb:234 in `block in each'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/nokogiri-1.13.9-arm64-darwin/lib/nokogiri/xml/node_set.rb:233 in `upto'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/nokogiri-1.13.9-arm64-darwin/lib/nokogiri/xml/node_set.rb:233 in `each'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/check/links.rb:7 in `run'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/runner.rb:132 in `block in check_parsed'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/runner.rb:123 in `each'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/runner.rb:123 in `check_parsed'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/runner.rb:115 in `load_file'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/runner.rb:106 in `block (3 levels) in process_files'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/async-2.2.1/lib/async/task.rb:107 in `block in run'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/async-2.2.1/lib/async/task.rb:243 in `block in schedule'
  0.0s     warn: Async::Task [oid=0xfa0] [ec=0xfb4] [pid=53492] [2022-11-25 10:32:53 +0100]
               | Task may have ended with unhandled exception.
               |   NoMethodError: undefined method `empty?' for true:TrueClass
               |
               |         obj.nil? || obj.empty?
               |                        ^^^^^^^
               |   → /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/utils.rb:12 in `blank?'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/attribute/url.rb:138 in `file_path'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/attribute/url.rb:128 in `absolute_path'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/check/links.rb:57 in `block in run'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/nokogiri-1.13.9-arm64-darwin/lib/nokogiri/xml/node_set.rb:234 in `block in each'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/nokogiri-1.13.9-arm64-darwin/lib/nokogiri/xml/node_set.rb:233 in `upto'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/nokogiri-1.13.9-arm64-darwin/lib/nokogiri/xml/node_set.rb:233 in `each'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/check/links.rb:7 in `run'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/runner.rb:132 in `block in check_parsed'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/runner.rb:123 in `each'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/runner.rb:123 in `check_parsed'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/runner.rb:115 in `load_file'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/runner.rb:106 in `block (3 levels) in process_files'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/async-2.2.1/lib/async/task.rb:107 in `block in run'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/async-2.2.1/lib/async/task.rb:243 in `block in schedule'
 0.01s     warn: Async::Task [oid=0xfc8] [ec=0xfdc] [pid=53492] [2022-11-25 10:32:53 +0100]
               | Task may have ended with unhandled exception.
               |   NoMethodError: undefined method `empty?' for true:TrueClass
               |
               |         obj.nil? || obj.empty?
               |                        ^^^^^^^
               |   → /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/utils.rb:12 in `blank?'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/attribute/url.rb:138 in `file_path'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/attribute/url.rb:128 in `absolute_path'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/check/links.rb:57 in `block in run'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/nokogiri-1.13.9-arm64-darwin/lib/nokogiri/xml/node_set.rb:234 in `block in each'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/nokogiri-1.13.9-arm64-darwin/lib/nokogiri/xml/node_set.rb:233 in `upto'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/nokogiri-1.13.9-arm64-darwin/lib/nokogiri/xml/node_set.rb:233 in `each'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/check/links.rb:7 in `run'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/runner.rb:132 in `block in check_parsed'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/runner.rb:123 in `each'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/runner.rb:123 in `check_parsed'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/runner.rb:115 in `load_file'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/runner.rb:106 in `block (3 levels) in process_files'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/async-2.2.1/lib/async/task.rb:107 in `block in run'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/async-2.2.1/lib/async/task.rb:243 in `block in schedule'
 0.01s     warn: Async::Task [oid=0xff0] [ec=0x1004] [pid=53492] [2022-11-25 10:32:53 +0100]
               | Task may have ended with unhandled exception.
               |   NoMethodError: undefined method `empty?' for true:TrueClass
               |
               |         obj.nil? || obj.empty?
               |                        ^^^^^^^
               |   → /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/utils.rb:12 in `blank?'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/attribute/url.rb:138 in `file_path'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/attribute/url.rb:128 in `absolute_path'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/check/links.rb:57 in `block in run'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/nokogiri-1.13.9-arm64-darwin/lib/nokogiri/xml/node_set.rb:234 in `block in each'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/nokogiri-1.13.9-arm64-darwin/lib/nokogiri/xml/node_set.rb:233 in `upto'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/nokogiri-1.13.9-arm64-darwin/lib/nokogiri/xml/node_set.rb:233 in `each'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/check/links.rb:7 in `run'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/runner.rb:132 in `block in check_parsed'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/runner.rb:123 in `each'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/runner.rb:123 in `check_parsed'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/runner.rb:115 in `load_file'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/runner.rb:106 in `block (3 levels) in process_files'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/async-2.2.1/lib/async/task.rb:107 in `block in run'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/async-2.2.1/lib/async/task.rb:243 in `block in schedule'
 0.01s     warn: Async::Task [oid=0x1018] [ec=0x102c] [pid=53492] [2022-11-25 10:32:53 +0100]
               | Task may have ended with unhandled exception.
               |   NoMethodError: undefined method `empty?' for true:TrueClass
               |
               |         obj.nil? || obj.empty?
               |                        ^^^^^^^
               |   → /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/utils.rb:12 in `blank?'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/attribute/url.rb:138 in `file_path'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/attribute/url.rb:128 in `absolute_path'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/check/links.rb:57 in `block in run'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/nokogiri-1.13.9-arm64-darwin/lib/nokogiri/xml/node_set.rb:234 in `block in each'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/nokogiri-1.13.9-arm64-darwin/lib/nokogiri/xml/node_set.rb:233 in `upto'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/nokogiri-1.13.9-arm64-darwin/lib/nokogiri/xml/node_set.rb:233 in `each'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/check/links.rb:7 in `run'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/runner.rb:132 in `block in check_parsed'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/runner.rb:123 in `each'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/runner.rb:123 in `check_parsed'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/runner.rb:115 in `load_file'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/runner.rb:106 in `block (3 levels) in process_files'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/async-2.2.1/lib/async/task.rb:107 in `block in run'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/async-2.2.1/lib/async/task.rb:243 in `block in schedule'
 0.01s     warn: Async::Task [oid=0x1040] [ec=0x1054] [pid=53492] [2022-11-25 10:32:53 +0100]
               | Task may have ended with unhandled exception.
               |   NoMethodError: undefined method `empty?' for true:TrueClass
               |
               |         obj.nil? || obj.empty?
               |                        ^^^^^^^
               |   → /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/utils.rb:12 in `blank?'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/attribute/url.rb:138 in `file_path'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/attribute/url.rb:128 in `absolute_path'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/check/links.rb:57 in `block in run'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/nokogiri-1.13.9-arm64-darwin/lib/nokogiri/xml/node_set.rb:234 in `block in each'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/nokogiri-1.13.9-arm64-darwin/lib/nokogiri/xml/node_set.rb:233 in `upto'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/nokogiri-1.13.9-arm64-darwin/lib/nokogiri/xml/node_set.rb:233 in `each'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/check/links.rb:7 in `run'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/runner.rb:132 in `block in check_parsed'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/runner.rb:123 in `each'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/runner.rb:123 in `check_parsed'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/runner.rb:115 in `load_file'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/runner.rb:106 in `block (3 levels) in process_files'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/async-2.2.1/lib/async/task.rb:107 in `block in run'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/async-2.2.1/lib/async/task.rb:243 in `block in schedule'
 0.01s     warn: Async::Task [oid=0x1068] [ec=0x107c] [pid=53492] [2022-11-25 10:32:53 +0100]
               | Task may have ended with unhandled exception.
               |   NoMethodError: undefined method `empty?' for true:TrueClass
               |
               |         obj.nil? || obj.empty?
               |                        ^^^^^^^
               |   → /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/utils.rb:12 in `blank?'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/attribute/url.rb:138 in `file_path'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/attribute/url.rb:128 in `absolute_path'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/check/links.rb:57 in `block in run'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/nokogiri-1.13.9-arm64-darwin/lib/nokogiri/xml/node_set.rb:234 in `block in each'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/nokogiri-1.13.9-arm64-darwin/lib/nokogiri/xml/node_set.rb:233 in `upto'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/nokogiri-1.13.9-arm64-darwin/lib/nokogiri/xml/node_set.rb:233 in `each'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/check/links.rb:7 in `run'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/runner.rb:132 in `block in check_parsed'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/runner.rb:123 in `each'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/runner.rb:123 in `check_parsed'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/runner.rb:115 in `load_file'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/runner.rb:106 in `block (3 levels) in process_files'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/async-2.2.1/lib/async/task.rb:107 in `block in run'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/async-2.2.1/lib/async/task.rb:243 in `block in schedule'
 0.01s     warn: Async::Task [oid=0x1090] [ec=0x10a4] [pid=53492] [2022-11-25 10:32:53 +0100]
               | Task may have ended with unhandled exception.
               |   NoMethodError: undefined method `empty?' for true:TrueClass
               |
               |         obj.nil? || obj.empty?
               |                        ^^^^^^^
               |   → /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/utils.rb:12 in `blank?'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/attribute/url.rb:138 in `file_path'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/attribute/url.rb:128 in `absolute_path'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/check/links.rb:57 in `block in run'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/nokogiri-1.13.9-arm64-darwin/lib/nokogiri/xml/node_set.rb:234 in `block in each'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/nokogiri-1.13.9-arm64-darwin/lib/nokogiri/xml/node_set.rb:233 in `upto'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/nokogiri-1.13.9-arm64-darwin/lib/nokogiri/xml/node_set.rb:233 in `each'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/check/links.rb:7 in `run'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/runner.rb:132 in `block in check_parsed'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/runner.rb:123 in `each'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/runner.rb:123 in `check_parsed'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/runner.rb:115 in `load_file'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/runner.rb:106 in `block (3 levels) in process_files'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/async-2.2.1/lib/async/task.rb:107 in `block in run'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/async-2.2.1/lib/async/task.rb:243 in `block in schedule'
 0.02s     warn: Async::Task [oid=0x10b8] [ec=0x10cc] [pid=53492] [2022-11-25 10:32:53 +0100]
               | Task may have ended with unhandled exception.
               |   NoMethodError: undefined method `empty?' for true:TrueClass
               |
               |         obj.nil? || obj.empty?
               |                        ^^^^^^^
               |   → /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/utils.rb:12 in `blank?'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/attribute/url.rb:138 in `file_path'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/attribute/url.rb:128 in `absolute_path'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/attribute/url.rb:118 in `exists?'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/check/images.rb:26 in `block in run'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/nokogiri-1.13.9-arm64-darwin/lib/nokogiri/xml/node_set.rb:234 in `block in each'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/nokogiri-1.13.9-arm64-darwin/lib/nokogiri/xml/node_set.rb:233 in `upto'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/nokogiri-1.13.9-arm64-darwin/lib/nokogiri/xml/node_set.rb:233 in `each'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/check/images.rb:9 in `run'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/runner.rb:132 in `block in check_parsed'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/runner.rb:123 in `each'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/runner.rb:123 in `check_parsed'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/runner.rb:115 in `load_file'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/runner.rb:106 in `block (3 levels) in process_files'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/async-2.2.1/lib/async/task.rb:107 in `block in run'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/async-2.2.1/lib/async/task.rb:243 in `block in schedule'
 0.02s     warn: Async::Task [oid=0x10e0] [ec=0x10f4] [pid=53492] [2022-11-25 10:32:53 +0100]
               | Task may have ended with unhandled exception.
               |   NoMethodError: undefined method `empty?' for true:TrueClass
               |
               |         obj.nil? || obj.empty?
               |                        ^^^^^^^
               |   → /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/utils.rb:12 in `blank?'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/attribute/url.rb:138 in `file_path'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/attribute/url.rb:128 in `absolute_path'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/attribute/url.rb:118 in `exists?'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/check/images.rb:26 in `block in run'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/nokogiri-1.13.9-arm64-darwin/lib/nokogiri/xml/node_set.rb:234 in `block in each'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/nokogiri-1.13.9-arm64-darwin/lib/nokogiri/xml/node_set.rb:233 in `upto'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/nokogiri-1.13.9-arm64-darwin/lib/nokogiri/xml/node_set.rb:233 in `each'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/check/images.rb:9 in `run'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/runner.rb:132 in `block in check_parsed'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/runner.rb:123 in `each'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/runner.rb:123 in `check_parsed'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/runner.rb:115 in `load_file'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/html-proofer-5.0.2/lib/html_proofer/runner.rb:106 in `block (3 levels) in process_files'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/async-2.2.1/lib/async/task.rb:107 in `block in run'
               |     /Users/<redacted>/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/async-2.2.1/lib/async/task.rb:243 in `block in schedule'

Shucks. I’ll take a look ASAP.

Ok, I think there is something wrong with the way that html-proofer is being run. Do you have any more information on those command-line arguments?

Here's what your error is saying:

 NoMethodError: undefined method `empty?' for true:TrueClass
               |
               |         obj.nil? || obj.empty?
               |                        ^^^^^^^

The obj is a boolean of true, and true does not have the .empty? method. That's correct.

This error is being raised from

html-proofer/lib/html_proofer/attribute/url.rb

Line 138 in bea6b3e

    
           path_dot_ext = path + @runner.options[:assume_extension] unless blank?(@runner.options[:assume_extension])

That means @runner.options[:assume_extension] is equal to true. But that's wrong, because assume_extension, per the documentation, is supposed to be a string:

Option	Description	Default
`assume_extension`	Automatically add specified extension to files for internal links, to allow extensionless URLs (as supported by most servers)	`.html`

So somewhere something is setting option[:assume_extension] = true. It's possibly coming from Jekyll or some other intermediary dependent.

You're right!

For some reason, I had :assume_extension => true in Jekyll's Rakefile.

Also, for anyone reading this. GitHub actions supports Ruby version >= 3.1, you have to set up the ci.yml correctly.