On 10/13/24 10:22 AM, Helmut Jarausch wrote: > Hi, > > I have somewhat broken my GenToo system. > (Nearly) all applications based on qt:5 die with > > Cannot mix incompatible Qt library (5.15.13) with this library (5.15.14) > > I have re-emerged all packages in dev-qt/ in slot 5, which didn't help. > I've tried strace but couldn't find the culprit. > > Does anybody know a means to find an old library or plugin which causes > this problem? > > Many thanks for your help, > Helmut
The general issue here is that applications which use Qt can do it via one of two methods: - link to Qt regularly, and only require a specific major version, i.e. all 5.* versions are valid and work fine. - link to Qt's private API, which means you must build against a specific PV and use that at runtime, and to enforce this, the resulting code will perform a check at runtime to see whether you are mixing versions, and if you are mixing versions it will error out with "Cannot mix incompatible Qt library (5.xx.xx) with this library (5.xx.xx)" You may recognize the latter error message. :) It is explicitly documented in the Gentoo policy for Qt packaging: https://wiki.gentoo.org/wiki/Project:Qt/Policies#Dependencies Packages which use private API headers of Qt *must* depend on a binding subslot operator to enforce that they are rebuilt every time Qt is updated. Packages which do NOT use private API headers should never depend on binding subslot operators, as they should not be rebuilt. In theory, all packages in ::gentoo should be correctly annotated as such. Maybe not all of them actually are... You can detect which ones have the issue. They will link to symbols such as "XXXXX@Qt_6_PRIVATE_API". I have a script which can detect that for existing binaries: https://git.sr.ht/~eschwartz/dotfiles/tree/master/item/bin/pkg-list-linked-libraries e.g. pkg-list-linked-libraries -s /usr/lib64 Qt_6_PRIVATE_API It will report a bunch of results for dev-qt/* packages too, but with a bit of filtering you can see what's relevant? -- Eli Schwartz
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