Merge branch 'disable-ref-generation-in-code-blocks' into 'master'

Disable reference generation in preformatted/code blocks

### Summary

If a user adds text in code or preformatted text via Markdown or HTML that contains `#XXX`, the system adds a note that issue `XXX` was mentioned. This is particularly annoying because we often list gdb backtrace dumps into our issues, and many issues get mentioned as a result. For example:

```
(gdb) bt
#0  0x00000000004004c4 in second () at main.cc:6
#1  0x00000000004004d2 in first () at main.cc:11
#2  0x00000000004004dd in main () at main.cc:17
(gdb)
```

### Steps to reproduce

1. In an issue, write the above text using Markdown or HTML tags (e.g. `<code>`, `<pre>`).
2. Observe that [issue 1](https://gitlab.com/gitlab-org/gitlab-ce/issues/1) and [issue 2](https://gitlab.com/gitlab-org/gitlab-ce/issues/2) have a note that says they were mentioned.

### Expected behavior

Everything enclosed in the code blocks should be ignored as references.

### Observed behavior

Issues get referenced unnecessarily.

### Fix

I've made `reference_extractor.rb` strip out HTML and Markdown blocks before processing. I considered running the raw text through the entire Markdown processor, but this seems overkill and perhaps could lead to some unintended side effects.

See merge request !365

1 files changed, 7 insertions, 1 deletions

diff --git a/lib/gitlab/reference_extractor.rb b/lib/gitlab/reference_extractor.rb
index 5b9772de168..1058d4c43d9 100644
--- a/lib/gitlab/reference_extractor.rb
+++ b/lib/gitlab/reference_extractor.rb
@@ -11,7 +11,13 @@ module Gitlab
     end
 
     def analyze(string, project)
-      parse_references(string.dup, project)
+      text = string.dup
+
+      # Remove preformatted/code blocks so that references are not included
+      text.gsub!(%r{<pre>.*?</pre>|<code>.*?</code>}m) { |match| '' }
+      text.gsub!(%r{^```.*?^```}m) { |match| '' }
+
+      parse_references(text, project)
     end
 
     # Given a valid project, resolve the extracted identifiers of the requested type to