Enable frozen strings in lib/banzai/filter/*.rbsh-freeze-banzai-filter-strings

Excludes a few filters that require more work:

* lib/banzai/filter/image_lazy_load_filter_spec.rb
* lib/banzai/filter/syntax_highlight_filter_spec.rb
* lib/banzai/filter/table_of_contents_filter_spec.rb

Part of #47424

39 files changed, 81 insertions, 0 deletions

diff --git a/changelogs/unreleased/sh-freeze-banzai-filter-strings.yml b/changelogs/unreleased/sh-freeze-banzai-filter-strings.yml
new file mode 100644
index 00000000000..37b397ea49f
--- /dev/null
+++ b/changelogs/unreleased/sh-freeze-banzai-filter-strings.yml
@@ -0,0 +1,5 @@
+---
+title: Enable frozen strings in lib/banzai/filter/*.rb
+merge_request: 20775
+author:
+type: performance
diff --git a/lib/banzai/filter/absolute_link_filter.rb b/lib/banzai/filter/absolute_link_filter.rb
index 1ec6201523f..04ec568eee3 100644
--- a/lib/banzai/filter/absolute_link_filter.rb
+++ b/lib/banzai/filter/absolute_link_filter.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'uri'
 
 module Banzai
diff --git a/lib/banzai/filter/abstract_reference_filter.rb b/lib/banzai/filter/abstract_reference_filter.rb
index b39b11009b3..ad0806df8e6 100644
--- a/lib/banzai/filter/abstract_reference_filter.rb
+++ b/lib/banzai/filter/abstract_reference_filter.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Banzai
   module Filter
     # Issues, Merge Requests, Snippets, Commits and Commit Ranges share
diff --git a/lib/banzai/filter/ascii_doc_post_processing_filter.rb b/lib/banzai/filter/ascii_doc_post_processing_filter.rb
index c9fcf057c5f..88439f06b5f 100644
--- a/lib/banzai/filter/ascii_doc_post_processing_filter.rb
+++ b/lib/banzai/filter/ascii_doc_post_processing_filter.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Banzai
   module Filter
     class AsciiDocPostProcessingFilter < HTML::Pipeline::Filter
diff --git a/lib/banzai/filter/autolink_filter.rb b/lib/banzai/filter/autolink_filter.rb
index 4a143baeef6..deda4b1872e 100644
--- a/lib/banzai/filter/autolink_filter.rb
+++ b/lib/banzai/filter/autolink_filter.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'uri'
 
 module Banzai
diff --git a/lib/banzai/filter/blockquote_fence_filter.rb b/lib/banzai/filter/blockquote_fence_filter.rb
index 7108e828c6d..ad367cc5efe 100644
--- a/lib/banzai/filter/blockquote_fence_filter.rb
+++ b/lib/banzai/filter/blockquote_fence_filter.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Banzai
   module Filter
     class BlockquoteFenceFilter < HTML::Pipeline::TextFilter
diff --git a/lib/banzai/filter/color_filter.rb b/lib/banzai/filter/color_filter.rb
index 6ab29ac281f..6d9bdb9cbd3 100644
--- a/lib/banzai/filter/color_filter.rb
+++ b/lib/banzai/filter/color_filter.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Banzai
   module Filter
     # HTML filter that renders `color` followed by a color "chip".
diff --git a/lib/banzai/filter/commit_range_reference_filter.rb b/lib/banzai/filter/commit_range_reference_filter.rb
index 01b3b0dafb9..d6b46236a49 100644
--- a/lib/banzai/filter/commit_range_reference_filter.rb
+++ b/lib/banzai/filter/commit_range_reference_filter.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Banzai
   module Filter
     # HTML filter that replaces commit range references with links.
diff --git a/lib/banzai/filter/commit_reference_filter.rb b/lib/banzai/filter/commit_reference_filter.rb
index 8cd92a1adba..c3e5ac41cb8 100644
--- a/lib/banzai/filter/commit_reference_filter.rb
+++ b/lib/banzai/filter/commit_reference_filter.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Banzai
   module Filter
     # HTML filter that replaces commit references with links.
diff --git a/lib/banzai/filter/commit_trailers_filter.rb b/lib/banzai/filter/commit_trailers_filter.rb
index 7b55e8b36f6..f49c4b403db 100644
--- a/lib/banzai/filter/commit_trailers_filter.rb
+++ b/lib/banzai/filter/commit_trailers_filter.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Banzai
   module Filter
     # HTML filter that replaces users' names and emails in commit trailers
diff --git a/lib/banzai/filter/emoji_filter.rb b/lib/banzai/filter/emoji_filter.rb
index 4eccd9d5ed5..c87948a30bf 100644
--- a/lib/banzai/filter/emoji_filter.rb
+++ b/lib/banzai/filter/emoji_filter.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Banzai
   module Filter
     # HTML filter that replaces :emoji: and unicode with images.
diff --git a/lib/banzai/filter/epic_reference_filter.rb b/lib/banzai/filter/epic_reference_filter.rb
index 265924abe24..e06e2fb3870 100644
--- a/lib/banzai/filter/epic_reference_filter.rb
+++ b/lib/banzai/filter/epic_reference_filter.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Banzai
   module Filter
     # The actual filter is implemented in the EE mixin
diff --git a/lib/banzai/filter/external_issue_reference_filter.rb b/lib/banzai/filter/external_issue_reference_filter.rb
index ed01a72ff9f..b4a7a44e109 100644
--- a/lib/banzai/filter/external_issue_reference_filter.rb
+++ b/lib/banzai/filter/external_issue_reference_filter.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Banzai
   module Filter
     # HTML filter that replaces external issue tracker references with links.
diff --git a/lib/banzai/filter/external_link_filter.rb b/lib/banzai/filter/external_link_filter.rb
index d6327ef31cb..2e6d742de27 100644
--- a/lib/banzai/filter/external_link_filter.rb
+++ b/lib/banzai/filter/external_link_filter.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Banzai
   module Filter
     # HTML Filter to modify the attributes of external links
diff --git a/lib/banzai/filter/gollum_tags_filter.rb b/lib/banzai/filter/gollum_tags_filter.rb
index bb9f488cd87..0c1bbd2d250 100644
--- a/lib/banzai/filter/gollum_tags_filter.rb
+++ b/lib/banzai/filter/gollum_tags_filter.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Banzai
   module Filter
     # HTML Filter for parsing Gollum's tags in HTML. It's only parses the
diff --git a/lib/banzai/filter/html_entity_filter.rb b/lib/banzai/filter/html_entity_filter.rb
index e008fd428b0..406c2d3c96b 100644
--- a/lib/banzai/filter/html_entity_filter.rb
+++ b/lib/banzai/filter/html_entity_filter.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'erb'
 
 module Banzai
diff --git a/lib/banzai/filter/image_link_filter.rb b/lib/banzai/filter/image_link_filter.rb
index f318c425962..884a94fb761 100644
--- a/lib/banzai/filter/image_link_filter.rb
+++ b/lib/banzai/filter/image_link_filter.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Banzai
   module Filter
     # HTML filter that wraps links around inline images.
diff --git a/lib/banzai/filter/inline_diff_filter.rb b/lib/banzai/filter/inline_diff_filter.rb
index 73e82a4d7e3..e9ddc6e0e3d 100644
--- a/lib/banzai/filter/inline_diff_filter.rb
+++ b/lib/banzai/filter/inline_diff_filter.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Banzai
   module Filter
     class InlineDiffFilter < HTML::Pipeline::Filter
diff --git a/lib/banzai/filter/issuable_reference_filter.rb b/lib/banzai/filter/issuable_reference_filter.rb
index 7addf09be73..2963cba91e8 100644
--- a/lib/banzai/filter/issuable_reference_filter.rb
+++ b/lib/banzai/filter/issuable_reference_filter.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Banzai
   module Filter
     class IssuableReferenceFilter < AbstractReferenceFilter
diff --git a/lib/banzai/filter/issuable_state_filter.rb b/lib/banzai/filter/issuable_state_filter.rb
index 1a415232545..d7fe012883d 100644
--- a/lib/banzai/filter/issuable_state_filter.rb
+++ b/lib/banzai/filter/issuable_state_filter.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Banzai
   module Filter
     # HTML filter that appends state information to issuable links.
diff --git a/lib/banzai/filter/issue_reference_filter.rb b/lib/banzai/filter/issue_reference_filter.rb
index 6877cae8c55..f85be042999 100644
--- a/lib/banzai/filter/issue_reference_filter.rb
+++ b/lib/banzai/filter/issue_reference_filter.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Banzai
   module Filter
     # HTML filter that replaces issue references with links. References to
diff --git a/lib/banzai/filter/label_reference_filter.rb b/lib/banzai/filter/label_reference_filter.rb
index a5f38046a43..b92e9e55bb9 100644
--- a/lib/banzai/filter/label_reference_filter.rb
+++ b/lib/banzai/filter/label_reference_filter.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Banzai
   module Filter
     # HTML filter that replaces label references with links.
diff --git a/lib/banzai/filter/markdown_filter.rb b/lib/banzai/filter/markdown_filter.rb
index 944363f17d3..cdf758472c1 100644
--- a/lib/banzai/filter/markdown_filter.rb
+++ b/lib/banzai/filter/markdown_filter.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Banzai
   module Filter
     class MarkdownFilter < HTML::Pipeline::TextFilter
diff --git a/lib/banzai/filter/math_filter.rb b/lib/banzai/filter/math_filter.rb
index b6e784c886b..9d1bc3cf60c 100644
--- a/lib/banzai/filter/math_filter.rb
+++ b/lib/banzai/filter/math_filter.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'uri'
 
 module Banzai
diff --git a/lib/banzai/filter/merge_request_reference_filter.rb b/lib/banzai/filter/merge_request_reference_filter.rb
index 10c40568006..7098767b583 100644
--- a/lib/banzai/filter/merge_request_reference_filter.rb
+++ b/lib/banzai/filter/merge_request_reference_filter.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Banzai
   module Filter
     # HTML filter that replaces merge request references with links. References
diff --git a/lib/banzai/filter/mermaid_filter.rb b/lib/banzai/filter/mermaid_filter.rb
index 65c131e08d9..7c8b165a330 100644
--- a/lib/banzai/filter/mermaid_filter.rb
+++ b/lib/banzai/filter/mermaid_filter.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Banzai
   module Filter
     class MermaidFilter < HTML::Pipeline::Filter
diff --git a/lib/banzai/filter/milestone_reference_filter.rb b/lib/banzai/filter/milestone_reference_filter.rb
index af8448937b3..328c8c1803b 100644
--- a/lib/banzai/filter/milestone_reference_filter.rb
+++ b/lib/banzai/filter/milestone_reference_filter.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Banzai
   module Filter
     # HTML filter that replaces milestone references with links.
diff --git a/lib/banzai/filter/plantuml_filter.rb b/lib/banzai/filter/plantuml_filter.rb
index 28933c78966..caba8955bac 100644
--- a/lib/banzai/filter/plantuml_filter.rb
+++ b/lib/banzai/filter/plantuml_filter.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "nokogiri"
 require "asciidoctor-plantuml/plantuml"
 
diff --git a/lib/banzai/filter/redactor_filter.rb b/lib/banzai/filter/redactor_filter.rb
index caf11fe94c4..1f091f594f8 100644
--- a/lib/banzai/filter/redactor_filter.rb
+++ b/lib/banzai/filter/redactor_filter.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Banzai
   module Filter
     # HTML filter that removes references to records that the current user does
diff --git a/lib/banzai/filter/reference_filter.rb b/lib/banzai/filter/reference_filter.rb
index 2411dd2cdfc..e5164e7f72a 100644
--- a/lib/banzai/filter/reference_filter.rb
+++ b/lib/banzai/filter/reference_filter.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Banzai
   module Filter
     # Base class for GitLab Flavored Markdown reference filters.
diff --git a/lib/banzai/filter/relative_link_filter.rb b/lib/banzai/filter/relative_link_filter.rb
index 262458a872a..8e838d04bad 100644
--- a/lib/banzai/filter/relative_link_filter.rb
+++ b/lib/banzai/filter/relative_link_filter.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'uri'
 
 module Banzai
diff --git a/lib/banzai/filter/sanitization_filter.rb b/lib/banzai/filter/sanitization_filter.rb
index 8275bb9e149..80b9d3d045f 100644
--- a/lib/banzai/filter/sanitization_filter.rb
+++ b/lib/banzai/filter/sanitization_filter.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Banzai
   module Filter
     # Sanitize HTML
diff --git a/lib/banzai/filter/set_direction_filter.rb b/lib/banzai/filter/set_direction_filter.rb
index c2976aeb7c6..45b259a2faf 100644
--- a/lib/banzai/filter/set_direction_filter.rb
+++ b/lib/banzai/filter/set_direction_filter.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Banzai
   module Filter
     # HTML filter that sets dir="auto" for RTL languages support
diff --git a/lib/banzai/filter/snippet_reference_filter.rb b/lib/banzai/filter/snippet_reference_filter.rb
index 881e10afb9f..f4b6edb6174 100644
--- a/lib/banzai/filter/snippet_reference_filter.rb
+++ b/lib/banzai/filter/snippet_reference_filter.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Banzai
   module Filter
     # HTML filter that replaces snippet references with links. References to
diff --git a/lib/banzai/filter/task_list_filter.rb b/lib/banzai/filter/task_list_filter.rb
index 9fa5f589f3e..ef35a49edcb 100644
--- a/lib/banzai/filter/task_list_filter.rb
+++ b/lib/banzai/filter/task_list_filter.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'task_list/filter'
 
 module Banzai
diff --git a/lib/banzai/filter/user_reference_filter.rb b/lib/banzai/filter/user_reference_filter.rb
index c7fa8a8119f..11960047e5b 100644
--- a/lib/banzai/filter/user_reference_filter.rb
+++ b/lib/banzai/filter/user_reference_filter.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Banzai
   module Filter
     # HTML filter that replaces user or group references with links.
diff --git a/lib/banzai/filter/video_link_filter.rb b/lib/banzai/filter/video_link_filter.rb
index 35cb10eae5d..0fb59c914c3 100644
--- a/lib/banzai/filter/video_link_filter.rb
+++ b/lib/banzai/filter/video_link_filter.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Banzai
   module Filter
     # Find every image that isn't already wrapped in an `a` tag, and that has
diff --git a/lib/banzai/filter/wiki_link_filter.rb b/lib/banzai/filter/wiki_link_filter.rb
index 269d5bf74fa..870721f895d 100644
--- a/lib/banzai/filter/wiki_link_filter.rb
+++ b/lib/banzai/filter/wiki_link_filter.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'uri'
 
 module Banzai
diff --git a/lib/banzai/filter/yaml_front_matter_filter.rb b/lib/banzai/filter/yaml_front_matter_filter.rb
index 58e3e81209e..295964dd75d 100644
--- a/lib/banzai/filter/yaml_front_matter_filter.rb
+++ b/lib/banzai/filter/yaml_front_matter_filter.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Banzai
   module Filter
     class YamlFrontMatterFilter < HTML::Pipeline::Filter