On 10/09/2015 04:16 PM, Luke Powers wrote: > There are a couple issues out there with similar reports (21646 21629 > 21628). > > Revert to 818f06eaa72d8e4f9ba314c1c2855613bf89f396 if you want to work > around the issue. I think I know what's going on. Stefan's change moved some of the syntax-propertize stuff from Lisp into C. Now Emacs core has a variable called syntax-propertize--done, known in C as syntax_propertize__done. We make it buffer-local using Fmake_variable_buffer_local, but that makes the variable buffer-local when it's _set_. Until it's set, the variable retains its global value, which lives in the C variable syntax_propertize__done. So if we syntax-propertize 1000 characters of buffer A, then find-file in buffer B, we think we've syntax-propertized up to position 1000 (the value of syntax_propertize__done) until we set it to something else. In the case of Python, if we have a triple quote in the first 1000 characters, we infloop.