version-protect a qt 4.7 feature

[rpavlik]

There's one line in mainwindow.cpp that uses a Qt 4.7 feature - everything else works on 4.6. I've put it in a #if guard. Tested on Qt 4.6.3 on Windows (VC 2008)

[kimmov]

No, this patch is rejected. We don't want to add support for different Qt versions by ifdefs. That will end up as an maintenance nightmare for our very limited resources. Not by this single occasion but I don't even want to open door for them.

You can implement the placeholder text functionality with Qt 4.6 too, just a little more work. Or we can drop the feature.

General rule is we must support the current Qt version. And if possible we should support the previous version. But again, the reality is couple of people is contributing for the GUI and our hands are full of work already without caring about older Qt versions.

Sure, people should read the Qt documentation and consider if it is essential to use features added only in latest Qt version. This is not first time such feature was used and for sure not the last.

So in summary, we can support later versions if/when patches get submitted and/or tickets filed so we get aware of the issue and can consider the pros and cons.

[rpavlik]

I wasn't suggesting a commitment to build on older versions - I kind of expect that if I'm using older libraries, things might not build properly. However, I wanted to build with an older version, and when I had this issue, I fixed it. I thought it would be appropriate to submit the patch fixing it - this is the very smallest change possible, literally just disabling the use of that UI feature on Qt versions before 4.7 using the standard Qt version checking macros. It seems wiser to me to selectively drop the feature on older Qt than drop it for all. No need to establish a rule "must build on 4.6 and 4.7" because of one patch - those of us who use an older version can assume the responsibility of keeping it working.

I realize my statement "this is a pretty simple fix to extend down to 4.6.3 at least" could be confusing - I didn't mean that I made a 4.6.3-specific version, just that I hadn't tried building with anything older than 4.6.3.

I was under the impression that a pull request of a feature branch, based off the latest master, was the standard way of "submitting a patch" and/or "filing a ticket". My apologies if I've transgressed some norm in your development community by doing things the wrong way. If there's an alternate way you'd like me to send you this bug and patch, and others I may find and fix in the future, please let me know.

[kimmov]

Maybe I should clarify that 'maintenance nightmare' -part a bit. It is not problem for compiling, and done that way that older versions disable what does not work is ok from compiling point of view. But think the situation somebody has two machines (say work and home) with different Qt versions. And he notes that in home machine there is the that hint text and when compiling at work there is not. These kind of things drive you nuts if you don't know what is going on. This is just the most obvious part.

Next lets say somebody implements new cool feature depending there is this hint text visible (having this feature just as an example, can be some other feature treated similarly of course). You can check the text from text edit in new and old Qt version so it is hard to find out that the feature is actually disabled for older Qt version. Now try to figure out why the new cool feature does not work when compiling with older Qt version... Do that in ticket when user complains about the cool feature not working for him.

So I'm definitely against having different behavior with different Qt versions.

[edward-san]

... just a curiosity, what about this pull request? Should it be closed or not?

[kimmov]

I guess that is up to somebody who wants to continue the GUI development...

[amai2012]

My opinion:
Close it - seems nobody will pick up. Unless written somewhere, add a small comment on https://sourceforge.net/apps/trac/cppcheck/ or http://cppcheck.sourceforge.net/devinfo/ or and state something like:
"cppcheck gui is supposed to be compatible with the previous and current version of the Qt framework. At the time of writing (September 2012) that means Qt 4.7 and 4.8 are supported."

[PKEuS]

I agree with kimmov in terms of "maintenance nightmare".