Merge branch '15624-multi-line-blockquotes-break-nested-single-line-blockquotes' into 'master'

[markdown] Multi-line blockquotes break nested single-line blockquotes See merge request !95967

Merge branch '15624-multi-line-blockquotes-break-nested-single-line-blockquotes' into 'master'
a894e3d6 · Luke Duncalfe · 16ad640a · b96c029b · a894e3d6 · a894e3d6
Commit a894e3d6 authored 2 years ago by Luke Duncalfe
--- a/config/feature_flags/development/markdown_corrected_blockquote.yml
+++ b/config/feature_flags/development/markdown_corrected_blockquote.yml
+---
+name: markdown_corrected_blockquote
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/95967
+rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/372089
+milestone: '15.4'
+type: development
+group: group::project management
+default_enabled: false
--- a/doc/user/markdown.md
+++ b/doc/user/markdown.md
@@ -611,9 +611,10 @@ Quote break.
 If this section isn't rendered correctly, [view it in GitLab](https://gitlab.com/gitlab-org/gitlab/-/blob/master/doc/user/markdown.md#multiline-blockquote).

 GitLab Flavored Markdown extends the standard Markdown by also supporting multi-line blockquotes
-fenced by `>>>`:
+fenced by `>>>`, with a blank line before and after the block:

 ```markdown
+
 >>>
 If you paste a message from somewhere else

@@ -621,6 +622,7 @@ that spans multiple lines,

 you can quote that without having to manually prepend `>` to every line!
 >>>
+
 ```

 >>>

--- a/lib/banzai/filter/blockquote_fence_filter.rb
+++ b/lib/banzai/filter/blockquote_fence_filter.rb
@@ -5,6 +5,37 @@ module Filter
    class BlockquoteFenceFilter < HTML::Pipeline::TextFilter
      REGEX = %r{
          #{::Gitlab::Regex.markdown_code_or_html_blocks}
+        |
+          (?=(?<=^\n|\A)>>>\ *\n.*\n>>>\ *(?=\n$|\z))(?:
+            # Blockquote:
+            # >>>
+            # Anything, including code and HTML blocks
+            # >>>
+
+            (?<=^\n|\A)>>>\ *\n
+            (?<quote>
+              (?:
+                  # Any character that doesn't introduce a code or HTML block
+                  (?!
+                      ^```
+                    |
+                      ^<[^>]+?>\ *\n
+                  )
+                  .
+                |
+                  # A code block
+                  \g<code>
+                |
+                  # An HTML block
+                  \g<html>
+              )+?
+            )
+            \n>>>\ *(?=\n$|\z)
+          )
+      }mx.freeze
+
+      OLD_REGEX = %r{
+          #{::Gitlab::Regex.markdown_code_or_html_blocks}
        |
          (?=^>>>\ *\n.*\n>>>\ *$)(?:
            # Blockquote:
@@ -40,7 +71,7 @@ def initialize(text, context = nil, result = nil)
      end

      def call
-        @text.gsub(REGEX) do
+        @text.gsub(regex) do
          if $~[:quote]
            # keep the same number of source lines/positions by replacing the
            # fence lines with newlines
@@ -50,6 +81,12 @@ def call
          end
        end
      end
+
+      private
+
+      def regex
+        Feature.enabled?(:markdown_corrected_blockquote) ? REGEX : OLD_REGEX
+      end
    end
  end
 end
--- a/spec/fixtures/blockquote_fence_after.md
+++ b/spec/fixtures/blockquote_fence_after.md
@@ -129,3 +129,27 @@ Double `>>>` inside HTML inside blockquote:
 >
 > Quote

+
+Requires a leading blank line
+>>>
+Not a quote
+>>>
+
+Requires a trailing blank line
+
+>>>
+Not a quote
+>>>
+Lorem
+
+Triple quoting is not our blockquote
+
+>>> foo
+>>> bar
+>>>
+> baz
+
+> boo
+>>> far
+>>>
+>>> faz
--- a/spec/fixtures/blockquote_fence_before.md
+++ b/spec/fixtures/blockquote_fence_before.md
@@ -129,3 +129,27 @@ Quote

 Quote
 >>>
+
+Requires a leading blank line
+>>>
+Not a quote
+>>>
+
+Requires a trailing blank line
+
+>>>
+Not a quote
+>>>
+Lorem
+
+Triple quoting is not our blockquote
+
+>>> foo
+>>> bar
+>>>
+> baz
+
+> boo
+>>> far
+>>>
+>>> faz
--- a/spec/lib/banzai/filter/blockquote_fence_filter_spec.rb
+++ b/spec/lib/banzai/filter/blockquote_fence_filter_spec.rb
@@ -14,10 +14,22 @@
    expect(output).to eq(expected)
  end

+  it 'does not require newlines at start or end of string' do
+    expect(filter(">>>\ntest\n>>>")).to eq("\n> test\n")
+  end
+
  it 'allows trailing whitespace on blockquote fence lines' do
    expect(filter(">>> \ntest\n>>> ")).to eq("\n> test\n")
  end

+  context 'when feature flag is turned off' do
+    it 'does not require a leading or trailing blank line' do
+      stub_feature_flags(markdown_corrected_blockquote: false)
+
+      expect(filter("Foo\n>>>\ntest\n>>>\nBar")).to eq("Foo\n\n> test\n\nBar")
+    end
+  end
+
  context 'when incomplete blockquote fences with multiple blocks are present' do
    it 'does not raise timeout error' do
      test_string = ">>>#{"\n```\nfoo\n```" * 20}"

--- a/spec/lib/banzai/pipeline/pre_process_pipeline_spec.rb
+++ b/spec/lib/banzai/pipeline/pre_process_pipeline_spec.rb
@@ -32,4 +32,21 @@

    expect(result[:output]).to eq('foo foo f...')
  end
+
+  context 'when multiline blockquote' do
+    it 'data-sourcepos references correct line in source markdown' do
+      markdown = <<~MD
+        >>>
+        foo
+        >>>
+      MD
+
+      pipeline_output = described_class.call(markdown, {})[:output]
+      pipeline_output = Banzai::Pipeline::PlainMarkdownPipeline.call(pipeline_output, {})[:output]
+      sourcepos = pipeline_output.at('blockquote')['data-sourcepos']
+      source_line = sourcepos.split(':').first.to_i
+
+      expect(markdown.lines[source_line - 1]).to eq "foo\n"
+    end
+  end
 end
--- a/spec/services/issues/build_service_spec.rb
+++ b/spec/services/issues/build_service_spec.rb
@@ -63,11 +63,13 @@ def build_issue(issue_params = {})

      it 'wraps the note in a blockquote' do
        note_text = "This is a string\n"\
+                    "\n"\
                    ">>>\n"\
                    "with a blockquote\n"\
                    "> That has a quote\n"\
                    ">>>\n"
        note_result = "    > This is a string\n"\
+                      "    > \n"\
                      "    > \n"\
                      "    > > with a blockquote\n"\
                      "    > > > That has a quote\n"\