Review Request 125139: Do not find XINPUT in FindXCB.cmake

[Martin Gräßlin]

> On Sept. 10, 2015, 7:42 nachm., Alex Merry wrote:
> > I'm wary about this change as it technically breaks module compatibility. Specifically, upgrading e-c-m could cause packages that formerly built to suddenly stop building, and they wouldn't even have any way to fix that. extragear/base/wacomtablet is an example of such a project.
> > 
> > I understand the wish to discourage cavalier use of XINPUT, though. Printing a warning if XINPUT was specifically requested is an option, but there's no way to know if someone calling `find_package(XCB)` will make use of the `XCB_XINPUT_FOUND` variable.
> > 
> > As a compromise, I'd be willing to consider a solution where XINPUT wasn't in the default set of things to search for, but could be specified explicitly (and that could be accompanied by a warning if you like). Note that this would require extending `ecm_find_package_parse_components` to allow a separate list of default components.
> > 
> > That solution shouldn't break anything too much, because if a project is not explicitly specifying components, then they are optional by default, so such a project will already need to cope in some way with XINPUT not being found (unless they are just letting `feature_summary` enforce the requirement).

> they wouldn't even have any way to fix that. extragear/base/wacomtablet is an example of such a project.

yes, that's my aim here. I do want to explicitly break wacomtablet, because currently it's just implicitly broken - which is worse IMHO. For the record: wacomtablet triggered this review request.

I would also not say that this is a breakage, but a bug fix. It's a bug that ecm finds xinput in the first place.


My suggestion as a comporomise is to add an option to allow finding it: 
set(ECM_XCB_I_KNOW_XINPUT_IS_NOT_STABLE_AND_WONT_WORK_ON_DISTROS TRUE)


- Martin


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On Sept. 10, 2015, 4:52 nachm., Martin Gräßlin wrote:
> 
> -----------------------------------------------------------
> This is an automatically generated e-mail. To reply, visit:
> https://git.reviewboard.kde.org/r/125139/
> -----------------------------------------------------------
> 
> (Updated Sept. 10, 2015, 4:52 nachm.)
> 
> 
> Review request for Extra Cmake Modules, Alex Merry and Harald Sitter.
> 
> 
> Repository: extra-cmake-modules
> 
> 
> Description
> -------
> 
> The XCB bindings for XINPUT are not finished and explictly disabled
> in XCB, see for xcb 1.11 [1].
> 
> Because of that most distributions do not include xinput. Trying to find
> xinput only creates problems - the distro of the user might provide it
> and they might not be aware that it's not available normally.
> 
> Thus let's not pretend it exists. Make life of everybody easier.
> 
> [1] http://cgit.freedesktop.org/xcb/libxcb/tree/configure.ac?id=1.11#n234
> 
> 
> Diffs
> -----
> 
>   find-modules/FindXCB.cmake b2a800f73058382ee84f7d93132a96f8852b4aa7 
> 
> Diff: https://git.reviewboard.kde.org/r/125139/diff/
> 
> 
> Testing
> -------
> 
> 
> Thanks,
> 
> Martin Gräßlin
> 
>

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