[Development] Qt 6 co-installability with Qt 5

André Pönitz apoenitz at t-online.de
Tue Feb 16 16:08:11 CET 2021

On Tue, Feb 16, 2021 at 04:35:25PM +0200, Ville Voutilainen wrote:
> On Tue, 16 Feb 2021 at 15:35, Kai Köhne <Kai.Koehne at qt.io> wrote:
> > And again, this is not something limited to Qt. Last time I checked,
> > the executable to run Python 3 on Windows is python.exe, not
> > python3.exe. On Debian at least it's python3. This hasn't blocked
> > Python from being perceived as overall beginner friendly ...
> Uh.. that seems like an apples-and-oranges comparison. On linux, it's
> expected and conventional that if you install both python 3 and python
> 2, both are available in the usual PATH, neither eclipses the other,
> and you can cd between python 2 and python 3 projects and run both,
> without switching environments or alternatives in between.
> On windows, I don't know what's conventional. In many cases, a
> shortcut is used that launches a command prompt with the right
> environment, and using two versions in the same command prompt just
> isn't done.
> > So, I would stick to qmake as canonical name, also in the
> > documentation. We can mention that it's sometimes called qmake6 on
> > Linux. But forcing everyone to change their habit and scripts just
> > for the sake of consistency with a fraction of the users that use a
> > global installation on Linux, and do not use update-alternatives, is
> > IMO not a good move.
> update-alternatives is a long-term system-wide configuration change.
> Changing PATH is a shorter-term user-specific one. That's how I switch
> between compilers, and I wouldn't dream of using update-alternatives
> to switch between them. Especially not on multi-user systems, where
> it's none of my business to change the alternative used for a system
> compiler for other people. I *can't* do an update-alternatives on a
> build server, and I *shouldn't*. That doesn't mean that a build server
> installation couldn't have both qt 5 and qt 6 installed in a
> system-wide location.
> Switching between qt 5 and qt 6 via update-alternatives is Just Wrong.
> If our approach requires it, our approach is broken.

[Responding to a more or less random mail in the thread here]

I agree that update-alternatives is Just Wrong for something that
should effectively be the user's decision (and not even a decision
for all of the user's projects but something that needs to be done

On the other hand I don't quite understand all the fuzz about the
Correct Global Name. When I as a user am not happy with someone's
decision on how to name a binary or if a distribution acts funnily or if
I am too lazy to change my muscle memory I set up a shell alias to do
what I want. 

The only problem with that is people looking over my shoulder sometimes
wonder why 'n' brings up firefox or 'gh' starts Qt Creator...


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