Fixes T5837. The problem is that the hash is being recognized as a commit hash. We currently fire the object monogram rules fairly early, but there's no real reason to do this. Move them after all of the hyperlink rules:
0 PhutilRemarkupEscapeRemarkupRule 100 PhutilRemarkupMonospaceRule 150 PhutilRemarkupDocumentLinkRule 175 PhrictionRemarkupRule <<< OLD OBJECT RULE POSITION 200 PhabricatorIconRemarkupRule 200 PhabricatorMemeRemarkupRule 200 DivinerSymbolRemarkupRule 350 DoorkeeperRemarkupRuleJIRA 350 PhabricatorYoutubeRemarkupRule 350 DoorkeeperRemarkupRuleAsana 400 PhutilRemarkupHyperlinkRule >>> NEW OBJECT RULE POSITION 500 PhabricatorImageMacroRemarkupRule 500 CustomInlineJIRA5Rule 500 PhabricatorMentionRemarkupRule 500 CustomInlineCodeRule 1000 PhutilRemarkupDelRule 1000 PhutilRemarkupBoldRule 1000 PhutilRemarkupItalicRule 1000 PhutilRemarkupUnderlineRule - The disadvantage of this approach is that `{F123, alt=go look at http://lol.com/ omg}` will parse the URL first, and then fail to resolve the object embed. This seems very rare / unusual. - The advantage is that all URLs which happen to have monograms in them work.
In the future, we could refine this by separating the rules, so the embed ({...}) versions fired at priority 200, while the normal versions fired at priority 450. We can wait for use cases, though. This is a little messy because the same code implements both rules.