From 189c5347bef6c182ed00e2b845cdce5678abbbce Mon Sep 17 00:00:00 2001
From: Robert Speicher <rspeicher@gmail.com>
Date: Fri, 10 Apr 2015 16:38:34 -0400
Subject: [PATCH] Add name-based referencing to LabelReferenceFilter

---
 lib/gitlab/markdown/label_reference_filter.rb |  43 +++++--
 .../markdown/label_reference_filter_spec.rb   | 113 +++++++++++++++---
 2 files changed, 130 insertions(+), 26 deletions(-)

diff --git a/lib/gitlab/markdown/label_reference_filter.rb b/lib/gitlab/markdown/label_reference_filter.rb
index 9753d0ac0f9..3bb84c50b93 100644
--- a/lib/gitlab/markdown/label_reference_filter.rb
+++ b/lib/gitlab/markdown/label_reference_filter.rb
@@ -13,25 +13,34 @@ module Gitlab
     class LabelReferenceFilter < HTML::Pipeline::Filter
       # Public: Find label references in text
       #
-      #   LabelReferenceFilter.references_in(text) do |match, label|
-      #     "<a href=...>#{label}</a>"
+      #   LabelReferenceFilter.references_in(text) do |match, id, name|
+      #     "<a href=...>#{Label.find(id)}</a>"
       #   end
       #
       # text - String text to search.
       #
-      # Yields the String match and the Integer label ID.
+      # Yields the String match, an optional Integer label ID, and an optional
+      # String label name.
       #
       # Returns a String replaced with the return of the block.
       def self.references_in(text)
         text.gsub(LABEL_PATTERN) do |match|
-          yield match, $~[:label].to_i
+          yield match, $~[:label_id].to_i, $~[:label_name]
         end
       end
 
       # Pattern used to extract label references from text
       #
-      # This pattern supports cross-project references.
-      LABEL_PATTERN = /~(?<label>\d+)/
+      # TODO (rspeicher): Limit to double quotes (meh) or disallow single quotes in label names (bad).
+      LABEL_PATTERN = %r{
+        ~(
+          (?<label_id>\d+)   | # Integer-based label ID, or
+          (?<label_name>
+            [^'"&\?,\s]+     | # String-based single-word label title
+            ['"][^&\?,]+['"]   # String-based multi-word label surrounded in quotes
+          )
+        )
+      }x
 
       # Don't look for references in text nodes that are children of these
       # elements.
@@ -68,8 +77,10 @@ module Gitlab
       def label_link_filter(text)
         project = context[:project]
 
-        self.class.references_in(text) do |match, id|
-          if label = project.labels.find_by(id: id)
+        self.class.references_in(text) do |match, id, name|
+          params = label_params(id, name)
+
+          if label = project.labels.find_by(params)
             url = url_for_label(project, label)
 
             klass = "gfm gfm-label #{context[:reference_class]}".strip
@@ -92,6 +103,22 @@ module Gitlab
         LabelsHelper.render_colored_label(label)
       end
 
+      # Parameters to pass to `Label.find_by` based on the given arguments
+      #
+      # id   - Integer ID to pass. If present, returns {id: id}
+      # name - String name to pass. If `id` is absent, finds by name without
+      #        surrounding quotes.
+      #
+      # Returns a Hash.
+      def label_params(id, name)
+        if id > 0
+          { id: id }
+        else
+          # TODO (rspeicher): Don't strip single quotes if we decide to only use double quotes for surrounding.
+          { name: name.tr('\'"', '') }
+        end
+      end
+
       def project
         context[:project]
       end
diff --git a/spec/lib/gitlab/markdown/label_reference_filter_spec.rb b/spec/lib/gitlab/markdown/label_reference_filter_spec.rb
index 49243484c95..2258889cb51 100644
--- a/spec/lib/gitlab/markdown/label_reference_filter_spec.rb
+++ b/spec/lib/gitlab/markdown/label_reference_filter_spec.rb
@@ -21,24 +21,6 @@ module Gitlab::Markdown
       end
     end
 
-    it 'links to a valid reference' do
-      doc = filter("See #{reference}")
-
-      expect(doc.css('a').first.attr('href')).to eq urls.
-        namespace_project_issues_url(project.namespace, project, label_name: label.name)
-    end
-
-    it 'links with adjacent text' do
-      doc = filter("Label (#{reference}.)")
-      expect(doc.to_html).to match(%r(\(<a.+><span.+>#{label.name}</span></a>\.\)))
-    end
-
-    it 'ignores invalid label IDs' do
-      exp = act = "Label ~#{label.id + 1}"
-
-      expect(filter(act).to_html).to eq exp
-    end
-
     it 'includes default classes' do
       doc = filter("Label #{reference}")
       expect(doc.css('a').first.attr('class')).to eq 'gfm gfm-label'
@@ -68,5 +50,100 @@ module Gitlab::Markdown
         expect(doc.css('a span').first.attr('style')).to match(/\Abackground-color: #\h{6}; color: #\h{6}\z/)
       end
     end
+
+    context 'Integer-based references' do
+      it 'links to a valid reference' do
+        doc = filter("See #{reference}")
+
+        expect(doc.css('a').first.attr('href')).to eq urls.
+          namespace_project_issues_url(project.namespace, project, label_name: label.name)
+      end
+
+      it 'links with adjacent text' do
+        doc = filter("Label (#{reference}.)")
+        expect(doc.to_html).to match(%r(\(<a.+><span.+>#{label.name}</span></a>\.\)))
+      end
+
+      it 'ignores invalid label IDs' do
+        exp = act = "Label ~#{label.id + 1}"
+
+        expect(filter(act).to_html).to eq exp
+      end
+    end
+
+    context 'String-based single-word references' do
+      let(:label)     { create(:label, name: 'gfm', project: project) }
+      let(:reference) { "~#{label.name}" }
+
+      it 'links to a valid reference' do
+        doc = filter("See #{reference}")
+
+        expect(doc.css('a').first.attr('href')).to eq urls.
+          namespace_project_issues_url(project.namespace, project, label_name: label.name)
+        expect(doc.text).to eq 'See gfm'
+      end
+
+      it 'links with adjacent text' do
+        skip 'FIXME (rspeicher): This will fail, because a period and parentheses are both currently valid in label names.'
+        doc = filter("Label (#{reference}.)")
+        expect(doc.to_html).to match(%r(\(<a.+><span.+>#{label.name}</span></a>\.\)))
+      end
+
+      it 'ignores invalid label names' do
+        exp = act = "Label ~#{label.name.reverse}"
+
+        expect(filter(act).to_html).to eq exp
+      end
+    end
+
+    context 'String-based multi-word references in quotes' do
+      let(:label) { create(:label, name: 'gfm references', project: project) }
+
+      context 'in single quotes' do
+        let(:reference) { "~'#{label.name}'" }
+
+        it 'links to a valid reference' do
+          doc = filter("See #{reference}")
+
+          expect(doc.css('a').first.attr('href')).to eq urls.
+            namespace_project_issues_url(project.namespace, project, label_name: label.name)
+          expect(doc.text).to eq 'See gfm references'
+        end
+
+        it 'links with adjacent text' do
+          doc = filter("Label (#{reference}.)")
+          expect(doc.to_html).to match(%r(\(<a.+><span.+>#{label.name}</span></a>\.\)))
+        end
+
+        it 'ignores invalid label names' do
+          exp = act = "Label ~'#{label.name.reverse}'"
+
+          expect(filter(act).to_html).to eq exp
+        end
+      end
+
+      context 'in double quotes' do
+        let(:reference) { %(~"#{label.name}") }
+
+        it 'links to a valid reference' do
+          doc = filter("See #{reference}")
+
+          expect(doc.css('a').first.attr('href')).to eq urls.
+            namespace_project_issues_url(project.namespace, project, label_name: label.name)
+          expect(doc.text).to eq 'See gfm references'
+        end
+
+        it 'links with adjacent text' do
+          doc = filter("Label (#{reference}.)")
+          expect(doc.to_html).to match(%r(\(<a.+><span.+>#{label.name}</span></a>\.\)))
+        end
+
+        it 'ignores invalid label names' do
+          exp = act = %(Label ~"#{label.name.reverse}")
+
+          expect(filter(act).to_html).to eq exp
+        end
+      end
+    end
   end
 end
-- 
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