The issue was that the user could open a C-family file and have it start
compiling in the background. While it is still compiling, he could trigger the
completion system with a member dot operator. Because the file was still
compiling for the very first time, the TranslationUnit object was yet not
created. Sadly, this meant that UpdatingTranslationUnit would return false, and
a new query request would be created, the GUI would hang until it was done
aaaaand terrible lag until the file was compiled.
This was a very rare edge case that could also only be triggered if it takes a
considerable amount of time to compile the file.
We now use the compilation working directory for a file that is specified in the
CompilationDatabase. We don't actually change the working directory of the
process, even temporarily (that would be annoying to users); we munge the flags
coming from the database so that all the relative paths in them are resolved to
absolute ones.
One more thing needs to be done though: the clang_completer.py file needs to not
trigger at all when YCM has been compiled without cpp support. FIX THAT!
This was intended to show the full clang output for a given diagnostic,
including notes. But it appears that libclang does not provide this
functionality...
If the user had code like "foo.bar" and then entered insert mode after the 'r'
in "bar", YCM would cause vim to hang.
The problem happened because a sorting task was created that would try to sort
on the latest clang result but none would be created because a clang task was
not created in this occasion. clang_data_ready_ would remain false and would
never be set to true, thus causing an infinite loop in SortingThreadMain since
the thread would forever wait on the mutex.
This was rectified with better handling of the clang results cache. Now the
cache is a full class and it also stores the line & column number of the
location for which the results were computed. Better logic is in place for the
cache invalidation.
The problem was caused by a race condition of all things. ClangCompleter would
set possibly_completions_ready when starting the first parse pass for the file
and then would try to extract diagnostics for the file before the diagnostics
were done. Technically this was not a problem because only an empty diagnostics
vector would be returned, but this triggered Syntastic because hey, we have some
diagnostics to show (even though we don't).
And then Syntastic would try to close the location list window during startup
when this operation is not available. Technically it's Syntastic's fault, but a
more principled way to check for done diagnostics is to return and use a future
for file parsing operations and this solution also works around the Syntastic
issue.
