Fix deep DOM tree problem in ansi2html

Currently the ansi2html color library will create growing DOM trees
under the following condition:
1. If the log has no sections, e.g. when it is too long and truncated
2. A lot of consecutive log items have the same color

4 files changed, 11 insertions, 14 deletions

diff --git a/lib/gitlab/ci/ansi2html.rb b/lib/gitlab/ci/ansi2html.rb
index 7a7679a1f6b..8335e1c1a7a 100644
--- a/lib/gitlab/ci/ansi2html.rb
+++ b/lib/gitlab/ci/ansi2html.rb
@@ -194,16 +194,15 @@ module Gitlab
         end
 
         def handle_new_line
-          css_classes = []
+          write_in_tag %{<br/>}
 
           if @sections.any?
             css_classes = %w[section line] + sections.map { |section| "s_#{section}" }
+            write_raw %{<span class="#{css_classes.join(' ')}"></span>}
           end
 
-          write_in_tag %{<br/>}
-          write_raw %{<span class="#{css_classes.join(' ')}"></span>} if css_classes.any?
           @lineno_in_section += 1
-          open_new_tag
+          ensure_open_new_tag
         end
 
         def handle_section(scanner)
diff --git a/spec/lib/gitlab/ci/ansi2html_spec.rb b/spec/lib/gitlab/ci/ansi2html_spec.rb
index 960c9aa9b83..4881ef15eab 100644
--- a/spec/lib/gitlab/ci/ansi2html_spec.rb
+++ b/spec/lib/gitlab/ci/ansi2html_spec.rb
@@ -143,11 +143,11 @@ describe Gitlab::Ci::Ansi2html do
   end
 
   it "replaces newlines with line break tags" do
-    expect(convert_html("\n")).to eq('<span><br/><span></span></span>')
+    expect(convert_html("\n")).to eq('<span><br/></span>')
   end
 
   it "groups carriage returns with newlines" do
-    expect(convert_html("\r\n")).to eq('<span><br/><span></span></span>')
+    expect(convert_html("\r\n")).to eq('<span><br/></span>')
   end
 
   describe "incremental update" do
@@ -195,7 +195,7 @@ describe Gitlab::Ci::Ansi2html do
       let(:pre_text) { "Hello\r" }
       let(:pre_html) { "<span>Hello\r</span>" }
       let(:text) { "\nWorld" }
-      let(:html) { "<span><br/><span>World</span></span>" }
+      let(:html) { "<span><br/>World</span>" }
 
       it_behaves_like 'stateable converter'
     end
diff --git a/spec/lib/gitlab/ci/trace/stream_spec.rb b/spec/lib/gitlab/ci/trace/stream_spec.rb
index 033bb83d1c3..af519f4bae6 100644
--- a/spec/lib/gitlab/ci/trace/stream_spec.rb
+++ b/spec/lib/gitlab/ci/trace/stream_spec.rb
@@ -65,9 +65,9 @@ describe Gitlab::Ci::Trace::Stream, :clean_gitlab_redis_cache do
           result = stream.html
 
           expect(result).to eq(
-            "<span>ヾ(´༎ຶД༎ຶ`)ﾉ<br/><span></span></span>"\
-            "<span class=\"term-fg-green\">許功蓋</span><span><br/>"\
-            "<span></span></span>")
+            "<span>ヾ(´༎ຶД༎ຶ`)ﾉ<br/></span>"\
+            "<span class=\"term-fg-green\">許功蓋</span>"\
+            "<span><br/></span>")
           expect(result.encoding).to eq(Encoding.default_external)
         end
       end
@@ -305,9 +305,7 @@ describe Gitlab::Ci::Trace::Stream, :clean_gitlab_redis_cache do
   describe '#html' do
     shared_examples_for 'htmls' do
       it "returns html" do
-        expect(stream.html).to eq(
-          "<span>12<br/><span>34<br/>"\
-          "<span>56</span></span></span>")
+        expect(stream.html).to eq("<span>12<br/>34<br/>56</span>")
       end
 
       it "returns html for last line only" do
diff --git a/spec/support/shared_examples/ci_trace_shared_examples.rb b/spec/support/shared_examples/ci_trace_shared_examples.rb
index f221b6afdec..e2b4b50d41d 100644
--- a/spec/support/shared_examples/ci_trace_shared_examples.rb
+++ b/spec/support/shared_examples/ci_trace_shared_examples.rb
@@ -7,7 +7,7 @@ shared_examples_for 'common trace features' do
     end
 
     it "returns formatted html" do
-      expect(trace.html).to eq("<span>12<br/><span>34</span></span>")
+      expect(trace.html).to eq("<span>12<br/>34</span>")
     end
 
     it "returns last line of formatted html" do