Error processing request: [ThreadError] deadlock; recursive locking

[apiology]

I found this while starting the LSP on a project without cached pins, and doing a hover-over. I'm guessing it's associated with these, but sadly no timestamp output to stderr:

[Trace - 08:27:18 AM] Received response 'textDocument/hover - (31629)' in 544ms.
Result: null

[WARN] Error processing request: [ThreadError] deadlock; recursive locking
[WARN] /Users/broz/src/solargraph/lib/solargraph/library.rb:678:in 'Thread::Mutex#synchronize'
/Users/broz/src/solargraph/lib/solargraph/library.rb:678:in 'Solargraph::Library#sync_catalog'
/Users/broz/src/solargraph/lib/solargraph/library.rb:599:in 'Solargraph::Library#cache_next_gemspec'
/Users/broz/src/solargraph/lib/solargraph/library.rb:684:in 'block in Solargraph::Library#sync_catalog'
/Users/broz/src/solargraph/lib/solargraph/library.rb:678:in 'Thread::Mutex#synchronize'
/Users/broz/src/solargraph/lib/solargraph/library.rb:678:in 'Solargraph::Library#sync_catalog'
/Users/broz/src/solargraph/lib/solargraph/library.rb:180:in 'Solargraph::Library#definitions_at'
/Users/broz/src/solargraph/lib/solargraph/language_server/host.rb:555:in 'Solargraph::LanguageServer::Host#definitions_at'
/Users/broz/src/solargraph/lib/solargraph/language_server/message/text_document/hover.rb:12:in 'Solargraph::LanguageServer::Message::TextDocument::Hover#process'
/Users/broz/src/solargraph/lib/solargraph/language_server/host.rb:105:in 'Solargraph::LanguageServer::Host#receive'
/Users/broz/src/solargraph/lib/solargraph/language_server/host/message_worker.rb:69:in 'Solargraph::LanguageServer::Host::MessageWorker#tick'
/Users/broz/src/solargraph/lib/solargraph/language_server/host/message_worker.rb:59:in 'block in Solargraph::LanguageServer::Host::MessageWorker#start'

I've got no reason to think this is a regression.