Code Nav Poc: Extend LSIF info with hover data

This MR adds documentation of a method for LSIF API

app/services/projects/lsif_data_service.rb

@@ -3,7 +3,7 @@
 module Projects
   class LsifDataService
     attr_reader :file, :project, :path, :commit_id,
-      :docs, :doc_ranges, :ranges, :def_refs
+      :docs, :doc_ranges, :ranges, :def_refs, :hover_refs
 
     CACHE_EXPIRE_IN = 1.hour
 
@@ -26,7 +26,8 @@ module Projects
           end_line: line_data.last,
           start_char: column_data.first,
           end_char: column_data.last,
-          definition_url: definition_url_for(def_refs[ref_id])
+          definition_url: definition_url_for(def_refs[ref_id]),
+          hover: highlighted_hover(hover_refs[ref_id])
         }
       end
     end
@@ -54,6 +55,7 @@ module Projects
       @doc_ranges = data['doc_ranges']
       @ranges = data['ranges']
       @def_refs = data['def_refs']
+      @hover_refs = data['hover_refs']
     end
 
     def doc_id
@@ -86,5 +88,16 @@ module Projects
 
       Gitlab::Routing.url_helpers.project_blob_path(project, definition_ref_path, anchor: line_anchor)
     end
+
+    def highlighted_hover(hovers)
+      hovers&.map do |hover|
+        # Documentation for a method which is added as comments on top of the method
+        # is stored as a raw string value in LSIF file
+        next { value: hover } unless hover.is_a?(Hash)
+
+        value = Gitlab::Highlight.highlight(nil, hover['value'], language: hover['language'])
+        { language: hover['language'], value: value }
+      end
+    end
   end
 end

spec/requests/api/lsif_data_spec.rb

@@ -61,7 +61,11 @@ describe API::LsifData do
             'end_line' => 8,
             'start_char' => 13,
             'start_line' => 8,
-            'definition_url' => project_blob_path(project, "#{commit.id}/morestrings/reverse.go", anchor: 'L5')
+            'definition_url' => project_blob_path(project, "#{commit.id}/morestrings/reverse.go", anchor: 'L5'),
+            'hover' => [{
+              'language' => 'go',
+              'value' => Gitlab::Highlight.highlight(nil, 'func Func2(i int) string', language: 'go')
+            }]
           })
         end
 

spec/services/projects/lsif_data_service_spec.rb

@@ -12,6 +12,10 @@ describe Projects::LsifDataService do
   let(:service) { described_class.new(artifact.file, project, params) }
 
   describe '#execute' do
+    def highlighted_value(value)
+      [{ language: 'go', value: Gitlab::Highlight.highlight(nil, value, language: 'go') }]
+    end
+
     context 'fetched lsif file', :use_clean_rails_memory_store_caching do
       it 'is cached' do
         service.execute
@@ -32,42 +36,48 @@ describe Projects::LsifDataService do
             end_line: 6,
             start_char: 5,
             start_line: 6,
-            definition_url: "#{path_prefix}/main.go#L7"
+            definition_url: "#{path_prefix}/main.go#L7",
+            hover: highlighted_value('func main()')
           },
           {
             end_char: 36,
             end_line: 3,
             start_char: 1,
             start_line: 3,
-            definition_url: "#{path_prefix}/main.go#L4"
+            definition_url: "#{path_prefix}/main.go#L4",
+            hover: highlighted_value('package "github.com/user/hello/morestrings" ("github.com/user/hello/morestrings")')
           },
           {
             end_char: 12,
             end_line: 7,
             start_char: 1,
             start_line: 7,
-            definition_url: "#{path_prefix}/main.go#L4"
+            definition_url: "#{path_prefix}/main.go#L4",
+            hover: highlighted_value('package "github.com/user/hello/morestrings" ("github.com/user/hello/morestrings")')
           },
           {
             end_char: 20,
             end_line: 7,
             start_char: 13,
             start_line: 7,
-            definition_url: "#{path_prefix}/morestrings/reverse.go#L11"
+            definition_url: "#{path_prefix}/morestrings/reverse.go#L11",
+            hover: highlighted_value('func Reverse(s string) string') + [{ value: "This method reverses a string \n\n" }]
           },
           {
             end_char: 12,
             end_line: 8,
             start_char: 1,
             start_line: 8,
-            definition_url: "#{path_prefix}/main.go#L4"
+            definition_url: "#{path_prefix}/main.go#L4",
+            hover: highlighted_value('package "github.com/user/hello/morestrings" ("github.com/user/hello/morestrings")')
           },
           {
             end_char: 18,
             end_line: 8,
             start_char: 13,
             start_line: 8,
-            definition_url: "#{path_prefix}/morestrings/reverse.go#L5"
+            definition_url: "#{path_prefix}/morestrings/reverse.go#L5",
+            hover: highlighted_value('func Func2(i int) string')
           }
         ])
       end
@@ -82,7 +92,8 @@ describe Projects::LsifDataService do
           end_line: 11,
           start_char: 1,
           start_line: 11,
-          definition_url: "/#{project.full_path}/-/blob/#{commit_id}/morestrings/reverse.go#L12"
+          definition_url: "/#{project.full_path}/-/blob/#{commit_id}/morestrings/reverse.go#L12",
+          hover: highlighted_value('var a string')
         })
       end
     end