bug#37620: 26.1; ada-mode 6.2.1 partial parsing occasionally hangs while moving point

[Ludovic Brenta]

X-Debbugs-CC: ada-mode-users@nongnu.org
Package: emacs, ada-mode
Version: 26.1
Severity: minor

I'm sorry but I cannot trigger this problem reliably.  Occasionally,
while simply moving in a source file (using up, down, page up, page
down etc.), the *Messages* buffer receives these errors:

Error during redisplay: (jit-lock-function 32410) signaled (error 
"wisi-process-parse not getting more text (or bad syntax in process 
output)")
Error during redisplay: (jit-lock-function 32910) signaled (error 
"wisi-process-parse not getting more text (or bad syntax in process 
output)")
Error during redisplay: (jit-lock-function 32940) signaled (error 
"wisi-process-parse not getting more text (or bad syntax in process 
output)")
Error during redisplay: (jit-lock-function 32971) signaled (error 
"wisi-process-parse not getting more text (or bad syntax in process 
output)")
Error during redisplay: (jit-lock-function 32973) signaled (error 
"wisi-process-parse not getting more text (or bad syntax in process 
output)")
Error during redisplay: (jit-lock-function 32988) signaled (error 
"wisi-process-parse not getting more text (or bad syntax in process 
output)")

and the redisplay freezes.  When this happens I usually have to do
M-x wiki-kill-parser to recover.

This happens once every 3-4 days, both on files that are syncatically
correct and on some being edited (I don't think it makes a difference
anymore as the partial parser is in use in both cases).  Has anyone
observed these errors before?  Could it be caused by moving point too
rapidly for the parser process to keep up?

--
Ludovic Brenta.