On Sunday 19 February 2012, Stephen Kelly wrote: > On Sunday, February 19, 2012 16:18:00 Alexander Neundorf wrote: > > On Sunday 19 February 2012, Stephen Kelly wrote: > > > > The only reason to distribute FindBlub for a CMake-aware project is > > > > to wrap up find_package NO_MODULE to produce a nicer message, but > > > > that > > > > is totally optional. If a project does want to distribute one for > > > > reference it should go in the -doc package, not in -dev, and should > > > > be > > > > put in share/doc/blub or the distro's equivalent. > > > > > > Good point. > > > > ...but nobody does it or knows it. > > Not many KDE developers at least. But KDE developers aren't really known > for CMake knowledge anyway. They generally get exposed to as little CMake > as possible, so I'm not sure they make a good target usecase.
Since 6 years KDE developers are my daily target usecase. I think they are the biggest existing group of cmake users out there. I don't think they are very different from other users. Also, what I always tried to do is to hide as little cmake stuff from them as possible. It shouldn't be seen as "magic" what is happening. All the macros etc. I wrote try to be in the same style as the original cmake commands. Look at how boost is using cmake. They are hiding it. Almost completely. I don't like how they use it. Because their users won't have a clue about cmake. > > > However, your suggestion above seems to indicate that that is exactly > > > what's being done? > > > > > > That will make this an error: > > > > > > cmake_required_version(2.8.8) > > > find_package(Qt5Core) > > > > > > Instead this more noisy version would need to be used: > > > > > > cmake_required_version(2.8.8) > > > find_package(Qt5Core CONFIG_MODE) > > > > Yes. > > And this is good. > > I disagree :) > > > Then the error message is "Could not find config file". Above it has to > > guess, and the developers will think that FindQt5.cmake is missing. > > How should they know that Qt5 ships Qt5Config.cmake files ? > > feature_summary() should tell them that they have to install the > development package for Qt5. > > Whether they need a Find module or a Config file, they still need to > install that, so they might as well do it first. Maybe they have already installed it, so they now think a FindQt5.cmake file is missing. It is good to have precise error messages. > > We always had FindFoo.cmake files for everything, including > > FindQt4.cmake. They will not think "oh, probably a Qt5Config.cmake could > > not be found". I am 99% sure with this. > > > > Somebody complained on google+ that cmake is a mess. > > If you don't know what to make of an error message, this won't help the > > perception. > > Without knowing what specifically they think is a mess, I don't know. I > expect that wasn't part of the + post. Specifics rarely are :) > > > Just yesterday when I was trying to build parts of kdelibs, and got all > > the complaints that neither a Find-module could be found nor a config-file > > could be found, I completely didn't know what the right way to fix them > > is. Is the Find-module missing, and I should add it, or is the package > > missing, because it should have installed a config file. > > It is usually easy at least with a package manager too see if libfoo-dev is > installed. > > That at least reduces the scope of the error to either CMake not finding > the config file (unlikely if a distro package is used, and if you See, and with the policy the scope is 100% reduced. Then I know what's wrong. > installed it yourself then you might know if you installed it) or > requiring a > FindFoo.cmake in your CMAKE_MODULE_PATH (and then you have to figure out > where it should come from). > > > I would have to check the sources of each of the missing packages to > > figure out whether it installs a config file or not. > > > > Making this explicit helps. > > This will also help in making the Config mode more visible, since it will > > not be "hidden" anymore. > > You know, people will see > > find_package(Qt5 CONFIG_MODE) > > and they might have a look what that "CONFIG_MODE" means. > > Without it, they won't. > > Maybe. > > The current branch isn't my preferred solution. Even after everyone has a > firm understanding of what CONFIG_MODE means, we'll still always need it. Yes. I don't see a problem with needing an additional keyword. This is what has happened with more or less all cmake commands: in the beginning they had simply a list of arguments, now most of them have two modes, the old one, and a new one which is a bit more verbose and more powerful. Compare find_package(Qt5) vs. find_package(Qt5 CONFIG_MODE) IMO here it's completely "in your face" that "I want a config file". The much better error message is IMO absolutely worth the one extra argument. Now and also in the future. Alex -- Powered by www.kitware.com Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html Please keep messages on-topic and check the CMake FAQ at: http://www.cmake.org/Wiki/CMake_FAQ Follow this link to subscribe/unsubscribe: http://public.kitware.com/cgi-bin/mailman/listinfo/cmake-developers
