Re: dropping QT4 support

[Rik]

On 12/14/2019 06:15 PM, Kai Torben Ohlhus wrote:
> On 12/14/19 1:15 PM, John W. Eaton wrote:
>> On 11/4/19 10:37 AM, Rik wrote:
>>> "John W. Eaton" <address@hidden> wrote:
>>>> We discussed dropping support for Qt4 back in March and June of this
>>>> year.  I think most of us agreed that it was a good idea but we
>>>> haven't followed through.
>>>>
>>>> If we agree that this is the right move for 6.1, then I'm willing to
>>>> do most or all of the work to fix the configure script and start
>>>> updating the sources immediately.  If we delay, I think we will have
>>>> to wait until after the 6.1 release as this is a fairly big change so
>>>> deserves sufficient time for testing.
>>> No objection.  The last Qt4 release was December, 2011 or
>>> approximately 8 years ago.  Even most long-term release distributions
>>> provide only 3 or 5 years support, so the number of users for Octave
>>> who require this feature is already very small.
>> I thought I would have time to work on this issue by now but all my
>> spare moments disappeared.  So for version 6 I think it is best to keep
>> support for Qt4 in the sources but consider it unsupported.  Then we can
>> move forward with removing support for it early in the version 7
>> development cycle.
>>
>> jwe
>>
>>
> Yes, might be too time consuming removing all Qt4/Qt5 branches for 6.1.
>  I can add a note to NEWS similar to 5.1.0 [1]
>
> ### Dependencies
>
> - The GUI requires Qt libraries.  The minimum Qt version supported is
>   Qt5.X.  Qt4 is no longer supported.
>
> What minor Qt5 revision X in 5.X does Octave support now?  5.9 is a Qt
> LTS, supported until middle of 2020 [2].  Compared to some Linux
> distributions:
>
> CentOS (7, June 2024 [3])          ==> 5.9.7  [12]
> CentOS (8,  May 2029 [3])          ==> 5.11.1 [12]
> Debian (Jessie,  June 2020 [7])    ==> 5.3.2  [4]
> Debian (Stretch, June 2022 [7])    ==> 5.7.1  [5]
> Debian (Buster,       2024 [7])    ==> 5.11.3 [6]
> Ubuntu (14.04 LTS, April 2022 [8]) ==> 5.2.1  [9]
> Ubuntu (16.04 LTS, April 2024 [8]) ==> 5.5.1  [10]
> Ubuntu (18.04 LTS, April 2028 [8]) ==> 5.9.5  [11]
>
> The only blockers here might be Debian Stretch and Ubuntu (16.04).  I
> suggest to require 5.9 LTS.  On servers, mostly relying on LTS versions
> a lot, there might not be a need for a Qt GUI in customized builds of
> newer Octave versions.  Functional octave versions with respective
> dependencies are provided by the distributors.
>
> Best,
> Kai
>
> [1]:
> https://hg.savannah.gnu.org/hgweb/octave/file/f426dd9750a3/etc/NEWS.5#l68
> [2]: https://en.wikipedia.org/wiki/Qt_version_history
> [3]: https://en.wikipedia.org/wiki/CentOS#End-of-support_schedule
> [4]: https://packages.debian.org/jessie/qtbase5-dev
> [5]: https://packages.debian.org/stretch/qtbase5-dev
> [6]: https://packages.debian.org/buster/qtbase5-dev
> [7]: https://en.wikipedia.org/wiki/Debian_version_history#Release_table
> [8]: https://en.wikipedia.org/wiki/Ubuntu_version_history#Table_of_versions
> [9]: https://packages.ubuntu.com/trusty/allpackages (search "qtbase5-dev")
> [10]: https://packages.ubuntu.com/xenial/qtbase5-dev
> [11]: https://packages.ubuntu.com/bionic/qtbase5-dev
> [12]: yum info qt5-qtbase-devel (on that system)
>
>

I checked in this changeset
(https://hg.savannah.gnu.org/hgweb/octave/rev/a8c5255c34b1) which announces
the change in the NEWS file and emits a warning about the deprecation if a
user runs configure with the option '--with-qt=4'.

Also, I am not able to compile the dev version of Octave with Qt4.  I filed
a bug about that here: https://savannah.gnu.org/bugs/index.php?57420.

--Rik