Bump --enable-compiler-plugins Clang baseline?

[Stephan Bergmann]

On 04/11/2020 16:31, Stephan Bergmann wrote:
> Since 
> <https://git.libreoffice.org/core/+/f23aa1a51cb1beea4ebe3a61ba0c9b3abd844fd9%5E!/> 
> "Bump compiler plugins Clang baseline to 5.0.2" from about two years 
> ago, the baseline for (Linux) --enable-compiler-plugins builds is Clang 
> 5.0.2.
> 
> Wasting time yesterday with 
> <https://gerrit.libreoffice.org/c/core/+/105234/1..4>, tracking down why 
> a loplugin:toolslong false positive started to appear with old Clang, I 
> wondered whether we could bump once again.  The benefit would be getting 
> rid of various #if CLANG_VERSION cruft across compilerplugins/clang/, 
> and potentially avoiding wasting time on similar issues in the future. 
> (Plus, we could revisit 
> <https://lists.freedesktop.org/archives/libreoffice/2019-November/083780.html> 
> "On using C++17 for compilerplugins (not possible for now)".)
> 
> The question is what the maximum Clang version would be that we could 
> bump to as a baseline for (Linux) --enable-compiler-plugins builds. (For 
> (implicit) --disable-compiler-plugins builds, baselines can stay as they 
> are for now.  And on macOS and Windows, I think I am the only one using 
> --enable-compiler-plugins, and I'm using Clang trunk there anyway.)
> 
> So, what is the maximum Clang version that people would be comfortable 
> with here?
> 
> lode already happens to provide a recipe to install Clang 9.0.1 on 
> Linux. so my suggestion---absent other constraints---would be to at 
> least bump to Clang 9, somewhat randomly.

as discussed on #libreoffice-dev yesterday:

> Feb 08 09:45:59 <sberg>	vmiklos, last time I brought up "Bump --enable-compiler-plugins Clang baseline?" back in 2020, you asked for Clang 7 for openSUSE; is that still what you'd ask for as a baseline? (maybe I'll finally find time to actually bump anything there...)
> Feb 08 09:50:03 <vmiklos>	sberg: today openSUSE has clang 12 (vs only 7 in the past)
> Feb 08 09:51:18 <sberg>	noelgrandin, ^ and you asked for Clang 10 for Ubuntu, what's your ask now?
> Feb 08 09:51:51 <noelgrandin>	sberg, I run clang trunk, that I compile myself
> Feb 08 09:52:06 <noelgrandin>	but kendy I think uses clang from Ubuntu or some such
> Feb 08 09:52:24 <noelgrandin>	current Ubuntu has clang 13
> Feb 08 09:52:50 <sberg>	ok, then lets settle on 12 for now, lets see if I get that working on the jenkins machine