Fix hashtag parsing on URLs with fragments (#9221) (#9326)

* Fix hashtag parsing on URLs with fragments

* Fix spec

decidim-core/lib/decidim/content_parsers/hashtag_parser.rb

@@ -18,7 +18,7 @@ class HashtagParser < BaseParser
 
       # Matches a hashtag if it starts with a letter or number
       # and only contains letters, numbers or underscores.
-      HASHTAG_REGEX = /\B#([[:alnum:]](?:[[:alnum:]]|_)*)\b/i.freeze
+      HASHTAG_REGEX = /\s\K\B#([[:alnum:]](?:[[:alnum:]]|_)*)\b/i.freeze
 
       # Replaces hashtags name with new or existing hashtags models global ids.
       #

decidim-core/spec/content_parsers/decidim/hashtag_parser_spec.rb

@@ -89,5 +89,25 @@ module Decidim
 
       it_behaves_like "find and stores the hashtags references"
     end
+
+    context "when content contains an URL with a fragment (aka anchor link)" do
+      let(:content) { "You can add an URL and this shouldn't be parsed http://www.example.org/path##{hashtag.name}" }
+      let(:parsed_content) { "You can add an URL and this shouldn't be parsed http://www.example.org/path#fragment" }
+
+      it "doesn't find the hashtag" do
+        expect(parser.metadata).to be_a(Decidim::ContentParsers::HashtagParser::Metadata)
+        expect(parser.metadata.hashtags).to eq([])
+      end
+    end
+
+    context "when written with an slash before the fragment" do
+      let(:content) { "You can add an URL and this shouldn't be parsed http://www.example.org/path/#fragment" }
+      let(:parsed_content) { "You can add an URL and this shouldn't be parsed http://www.example.org/path/#fragment" }
+
+      it "doesn't find the hashtag" do
+        expect(parser.metadata).to be_a(Decidim::ContentParsers::HashtagParser::Metadata)
+        expect(parser.metadata.hashtags).to eq([])
+      end
+    end
   end
 end