Add latest changes from gitlab-org/security/gitlab@13-12-stable-ee

1 files changed, 19 insertions, 2 deletions

diff --git a/lib/banzai/filter/truncate_source_filter.rb b/lib/banzai/filter/truncate_source_filter.rb
index 44f88b253d9..a21d4a44295 100644
--- a/lib/banzai/filter/truncate_source_filter.rb
+++ b/lib/banzai/filter/truncate_source_filter.rb
@@ -3,12 +3,29 @@
 module Banzai
   module Filter
     class TruncateSourceFilter < HTML::Pipeline::TextFilter
+      CHARACTER_COUNT_LIMIT = 1.megabyte
+      USER_MSG_LIMIT = 10_000
+
       def call
-        return text unless context.key?(:limit)
+        # don't truncate if it's a :blob and no limit is set
+        return text if context[:text_source] == :blob && !context.key?(:limit)
+
+        limit = context[:limit] || CHARACTER_COUNT_LIMIT
+
+        # no sense in allowing `truncate_bytes` to duplicate a large
+        # string unless it's too big
+        return text if text.bytesize <= limit
 
         # Use three dots instead of the ellipsis Unicode character because
         # some clients show the raw Unicode value in the merge commit.
-        text.truncate_bytes(context[:limit], omission: '...')
+        trunc = text.truncate_bytes(limit, omission: '...')
+
+        # allows us to indicate to the user that what they see is a truncated copy
+        if limit > USER_MSG_LIMIT
+          trunc.prepend("_The text is longer than #{limit} characters and has been visually truncated._\n\n")
+        end
+
+        trunc
       end
     end
   end