[PyQt] PyQt5-sip 4.19.13 required for PyQt5 5.11.3 but not in python package

[Kyle Altendorf]

On November 4, 2018 10:39:01 AM EST, Damon Lynch <damonlynch at gmail.com> wrote:
>On Sat, Nov 3, 2018 at 10:53 PM Kyle Altendorf <sda at fstab.net> wrote:
>
>> On 2018-11-03 17:39, Damon Lynch wrote:
>>
>> > Unless I'm mistaken, for now the latest PyQt5 requires the latest
>> > PyQt5_sip, but the packaging of PyQt5 does not specify this
>> > requirement.
>> >
>> > For example, on Fedora 29:
>> >
>> > [damon at localhost ~]$ pip3 install --user PyQt5
>> > Requirement already satisfied: PyQt5 in
>> > ./.local/lib/python3.7/site-packages (5.11.3)
>> > Requirement already satisfied: PyQt5_sip<4.20,>=4.19.11 in
>> > /usr/lib64/python3.7/site-packages (from PyQt5) (4.19.12)
>>
>> So this did nothing because it found a pre-existing --user install. 
>It
>> didn't install the PyPI PyQt5_sip package because it found a
>> 'satisfactory' system installed copy.
>
>
>
>Yes you're quite right about the system package part. I somehow missed
>that
>the system PyQt5_sip was being used instead of one in the local user's
>site
>packages. I know why: I assumed that when PyQt5 is installed from pip,
>so
>would PyQt5_sip. In this case, it appears it was not. I don't know how
>that
>came to be, because as far as I know, when you install PyQt5 locally
>from
>pypi, PyQt5_sip should always be installed alongside it. I don't know
>if
>that's unique to pip in Fedora or its indicative of something else.

It's because you are mixing...  --user isn't isolated, it's overlayed over the system packages. Running pip as root mixes pip/dnf as well as filesystem space.  With --user you are still mixing pip/dnf but I'm separate filesystem space. It's still not good and explains what happened here. Use virtualenvs or venvs and remind them anytime something funny happens.  They should be disposable.

>In that case, for me the upshot of this is that one cannot trust the
>reliability of pip's dependency resolution, and PyQt5_sip must be
>manually
>installed / upgraded every time PyQt5 is installed / upgraded.
>
>Thanks for sharing your thoughts re pip and sudo. I never use sudo with
>pip.
>
>Best,
>Damon