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Am Mittwoch, 11. März 2020, 18:54:43 CET schrieb Grant Edwards: |
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> Background: a utility written in Python that I use regularly |
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> (weasyprint) was out-of-date and is being dropped from Gentoo's |
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> package database. I tried (and faield) to creaate an ebuild for a |
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> more recent version. So I ended up doing |
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> |
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> $ pip3 install --user weasyprint |
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> |
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> That installed weasyprint and a few depdendancies (tinycss2, |
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> defusedxml, ciarocffi) under ~/.local/{bin,lib64}. |
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> |
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> Question: |
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> |
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> Can those dependancies installed under ~/.local cause problems for |
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> things that were installed using standard ebuilds which require |
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> older/other versions of those libraries (which were installed using |
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> standard ebuilds)? |
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> |
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> For example, weasyprint requires cairosvg 2.4, and 2.4.2 was installed |
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> under .local via the pip3 command shown above. |
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> |
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> My stable cairosvg is 2.0.3 and it is installed in the usual "system" |
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> location /usr/lib64/python3.6/site-packages by the normal "emerge" |
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> process. [IIRC, at one point I tried unmasking 2.4.2, but that caused |
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> a cascade of other problems.] |
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> |
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> Q: Under what conditions will having a second installation of a Python |
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> library under .local cause problems? |
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|
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IIUC you shouldn't have any problems, simply because ~/.local/ is not part of |
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the system python's module search path: |
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|
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% python3 |
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Python 3.6.10 (default, Feb 26 2020, 01:09:02) |
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[GCC 9.2.0] on linux |
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Type "help", "copyright", "credits" or "license" for more information. |
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>>> import sys |
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>>> sys.path |
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['', '/usr/lib64/python36.zip', '/usr/lib64/python3.6', '/usr/lib64/python3.6/ |
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lib-dynload', '/usr/lib64/python3.6/site-packages'] |
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|
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So whatever uses the system Python will not see your local packages unless it |
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manipulates sys.path appropriately (which I don't think any sane software ever |
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does). |
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|
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A virtualenv, as suggested by Mark, would have its own module search paths. I |
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don't know if those ever *can* include the system paths (because they normally |
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use their own Python binary with its own standard library and site-packages), |
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but none of the environments I have do, e.g.: |
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|
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% conda activate base |
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% python |
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(base) |
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Python 3.7.4 (default, Aug 13 2019, 20:35:49) |
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[GCC 7.3.0] :: Anaconda, Inc. on linux |
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Type "help", "copyright", "credits" or "license" for more information. |
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>>> import sys |
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>>> sys.path |
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['', '/home/marcec/.miniconda3/lib/python37.zip', '/home/marcec/.miniconda3/ |
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lib/python3.7', '/home/marcec/.miniconda3/lib/python3.7/lib-dynload', '/home/ |
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marcec/.miniconda3/lib/python3.7/site-packages'] |
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>>> |
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|
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(Granted it's conda and not plain virtualenv, but I think the principles are |
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the same.) |
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|
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HTH |
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-- |
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Marc Joliet |
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-- |
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"People who think they know everything really annoy those of us who know we |
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don't" - Bjarne Stroustrup |
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