uicheck

[Stephan Bergmann]

Of the four <https://ci.libreoffice.org/job/gerrit_master/> buildsteps 
(i.e., the Jenkins bots that check your Gerrit changes), only 
gerrit_linux_clang_dbgutil runs uicheck (i.e., executing the various 
UITests).  Unfortunately, those UITests have a tendency to hang if they 
fail, causing a Gerrit change's gerrit_linux_clang_dbgutil build to 
abort.  (Unfortunately, again, without much indication of what failed, 
see 
<https://gerrit.libreoffice.org/c/lode/+/91496/2#message-8e52d669f48a9edb5f183d1221164784059e8959>.)

So if Jenkins fails for one of your Gerrit changes with an aborted 
gerrit_linux_clang_dbgutil, chances are high that that is due to some 
failed UITest.  To verify that locally:

* If you develop on Linux, run `make check` (but you should have done so 
before submitting the change to Gerrit anyway).  If it hangs, debug to 
find out why and fix.

* If you develop on Windows:

** First run `make check` to find out whether it could be anything other 
than a UITest that hung the Jenkins build ("check" includes "uicheck" 
only on Linux, not on other platforms like Windows, and only 
gerrit_linux_clang_dbgutil runs a full "check"; and you should have run 
`make check` locally before submitting the change to Gerrit anyway).

** Since 
<https://git.libreoffice.org/core/+/24e1563b5db3de5abac0d4fd0f737ec319e703e8%5E%21> 
"Handle more Windows \r\n vs. \n differences in UITests", you should be 
able to run `make uicheck` on Windows, with the following caveats:

*** It does not run headless, so pops up windows on your machine. 
Better stay away from the machine while the build runs.

*** It appears to be unreliable when run with a build parallelism > 1. 
So if you configure --without-parallelism, pass -j1 or no -j at all to 
`make uicheck`.  I have no idea what you need to do if you use the 
implicit, unhelpful --with-parallelism, though.  (And I didn't bother to 
check what causes the unreliability.  One source most likely are the 
dubious UITests that use the clipboard, see the email thread starting at 
<https://lists.freedesktop.org/archives/libreoffice/2020-April/084822.html> 
"Linux SAL_USE_VCLPLUGIN=svp and the clipboard".)

** Again, if it hangs, debug to find out why and fix.

* If you develop on macOS (or anything else), you're likely lost for now.