# CMake description of ParaView 6.x dose not match the actual requirements about Python.

**URL:** https://discourse.paraview.org/t/cmake-description-of-paraview-6-x-dose-not-match-the-actual-requirements-about-python/17552
**Category:** Development
**Tags:** proposal, python
**Created:** [May 7, 2026, 11:20am UTC](https://discourse.paraview.org/t/cmake-description-of-paraview-6-x-dose-not-match-the-actual-requirements-about-python/17552 "2026-05-07T11:20:08Z")
**Posts on this page:** 7
**Page:** 1

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### Author: ![earth2001y](https://discourse.paraview.org/user_avatar/discourse.paraview.org/earth2001y/32/8370_2.png) [@earth2001y](https://discourse.paraview.org/u/earth2001y)
#### Post date: [May 7, 2026, 11:20am UTC](https://discourse.paraview.org/t/cmake-description-of-paraview-6-x-dose-not-match-the-actual-requirements-about-python/17552/1 "2026-05-07T11:20:08Z")

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pvpython of ParaView 6.1 build from source code on Rocky Linux 8 doesn’t work `import paraview.simple` with following message.

```auto
>>> import paraview.simple
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/path/to/paraview/6.1.0/lib64/python3.6/site-packages/paraview/ __init__.py", line 38
    def __call__ (self, arg, /):
                            ^
SyntaxError: invalid syntax
>>>

```

I know those the error occurs because to default Python version of RockyLinux 8 is 3.6 and “Positional-Only Parameters” is available since Python 3.8.  
However, cmake enabling python had been succeeded and FindPython had said “minimum required is 3.4” in cmake was running.

I think this inconsistency should be corrected.

best regards,

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### Author: ![Lucas\_Givord](https://discourse.paraview.org/user_avatar/discourse.paraview.org/lucas_givord/32/6851_2.png) [@Lucas\_Givord](https://discourse.paraview.org/u/Lucas_Givord)
#### Post date: [May 7, 2026, 3:08pm UTC](https://discourse.paraview.org/t/cmake-description-of-paraview-6-x-dose-not-match-the-actual-requirements-about-python/17552/2 "2026-05-07T15:08:06Z")

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Hi @earth2001y,

The problem concerns also VTK, we talked about that few months ago when we remove support for python wheel generated in the CI for 3.8 : [https://gitlab.kitware.com/vtk/vtk/-/work\_items/19748#note\_1684578](https://gitlab.kitware.com/vtk/vtk/-/work_items/19748#note_1684578)

I think also that we should update the minimal version, especially as it’s not tested.

@ben.boeckel @cory.quammen @mwestphal wdyt ?

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### Author: ![mwestphal](https://discourse.paraview.org/user_avatar/discourse.paraview.org/mwestphal/32/17_2.png) [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [May 7, 2026, 3:09pm UTC](https://discourse.paraview.org/t/cmake-description-of-paraview-6-x-dose-not-match-the-actual-requirements-about-python/17552/3 "2026-05-07T15:09:04Z")

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Definitely, should be simple to do.

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### Author: ![cory.quammen](https://discourse.paraview.org/user_avatar/discourse.paraview.org/cory.quammen/32/11193_2.png) [@cory.quammen](https://discourse.paraview.org/u/cory.quammen)
#### Post date: [May 7, 2026, 3:23pm UTC](https://discourse.paraview.org/t/cmake-description-of-paraview-6-x-dose-not-match-the-actual-requirements-about-python/17552/4 "2026-05-07T15:23:51Z")

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We’re checking on whether we have a need to support Python 3.6 and will follow up here.

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### Author: ![ben.boeckel](https://discourse.paraview.org/letter_avatar_proxy/v4/letter/b/ea5d25/32.png) [@ben.boeckel](https://discourse.paraview.org/u/ben.boeckel)
#### Post date: [May 7, 2026, 8:43pm UTC](https://discourse.paraview.org/t/cmake-description-of-paraview-6-x-dose-not-match-the-actual-requirements-about-python/17552/5 "2026-05-07T20:43:16Z")

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Note that the policy for VTK is (as of `master`): 3.10 minimum _tested_, but patches welcome to support back to 3.4. Not dissimilar to our MinGW support policy FWIW.

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### Author: ![mwestphal](https://discourse.paraview.org/user_avatar/discourse.paraview.org/mwestphal/32/17_2.png) [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [May 7, 2026, 8:46pm UTC](https://discourse.paraview.org/t/cmake-description-of-paraview-6-x-dose-not-match-the-actual-requirements-about-python/17552/6 "2026-05-07T20:46:59Z")

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TBH I’m not a fan of not enforcing the tested minimum. Its kinda false advertising.

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### Author: ![ben.boeckel](https://discourse.paraview.org/letter_avatar_proxy/v4/letter/b/ea5d25/32.png) [@ben.boeckel](https://discourse.paraview.org/u/ben.boeckel)
#### Post date: [May 8, 2026, 12:55am UTC](https://discourse.paraview.org/t/cmake-description-of-paraview-6-x-dose-not-match-the-actual-requirements-about-python/17552/7 "2026-05-08T00:55:17Z")

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Right now, the minimum is lifted if `VTK_REMOVE_LEGACY` is set. This is the last usage of the variable in VTK, so if you want to introduce a variable to replace it that defaults to “raise the minimum” so that supporting pre-3.10 is an explicit opt-in, that sounds good to me.