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> don't mess with the system-provided Python environments for specific applications you are working with Right, but then just use pip install --user instead of

> don't mess with the system-provided Python environments for specific applications you are working with Right, but then just use pip install --user instead of a virtualenv. Actually --user is the default now when running pip install from non-root user, so, just pip install as a user will work and not mess with the system packages, just don't do sudo pip install.

gjulianm 5y ago
I've run into problems when running pip install --user. Someone installs a package in the user environment, and that works. But later you'll install a package in a shared virtualenv (because a Python program needs to run as a service or by another users or whatever) and pip doesn't install it because it's already on the user environment. However, other users don't have access to that environment and they will have an import error that you won't see from your user. Not to mention that installing every dependency in the same environment is a recipe for both disaster with version conflicts and bloat when you don't really know which packages belong to which applications.
- 1337shadow 5y ago
  Interesting problem but I think it's more a problem in virtualenv, which don't use global site package by default, I'm surprised that it uses user site packages by default. However, installing every dependency in the same environment is also what distro package managers do, I don't see that as a recipe for disaster, it all depends how well the said packages are maintained in which case just upgrading them should fix whatever problem.
  - gjulianm 5y ago
    > However, installing every dependency in the same environment is also what distro package managers do, I don't see that as a recipe for disaster, Distro packages are done in a way where it's hard to get conflicts. I haven't found an instance where python3-X and python3-Y can't be installed because one requires python3-Z v1.2 and the other python3-Z v2.1. With Python packages, that happens way more often. Also, distro package managers keep track of everything installed, while python ones (at least pip I'm 100% sure) don't. You could install a package which upgrades another one, and that breaks another that you had installed before and pip won't say a word.
    - 1337shadow 5y ago
      > I haven't found an instance where python3-X and python3-Y can't be installed because one requires python3-Z v1.2 and the other python3-Z v2.1. With Python packages, that happens way more often. Exactly, because the packages were created/updated at a point in time were they were compatible: a distro ships python 3.x with packages of python modules that are compatible with python 3.x. Now if you as a user want to use a python package that works with python 3.y, you either have to wait, or install python 3.y, or use a container of python 3.y. Again, if all python package were up to date as in "working together at this point in time" then `pip upgrade` would work. > Also, distro package managers keep track of everything installed, while python ones (at least pip I'm 100% sure) don't. Are you sure you checked in the `*.dist-info` directories? There should be one per package, containing: a METADATA file, with all dependency versions, a RECORD file, with every installed file and their hash, and much more! see for yourself ;) > You could install a package which upgrades another one, and that breaks another that you had installed before and pip won't say a word. Let's agree to disagree right there: - in your point of view: this is a problem in pip - in my point of view: this is a maintenance problem in the python packages themselves, caused by the general practice of pinning
      - gjulianm 5y ago
        > Again, if all python package were up to date as in "working together at this point in time" then `pip upgrade` would work. That is impossible, it will never happen. Packages will have different maintenance cycles, some will get deprecated, others abandoned... You can't base your upgrade policy on an impossible situation. > Are you sure you checked in the `*.dist-info` directories? There should be one per package, containing: a METADATA file, with all dependency versions, a RECORD file, with every installed file and their hash, and much more! see for yourself ;) I know, but pip doesn't track all of those all the time. An example that has happened to me multiple times: install package X that depends on Y <= 1.0. Good, pip installs the proper version. Now, on another command, install package Z that depends on Y >= 2.0. Pip will install Y >= 2.0 and won't care that package X is now broken. > - in my point of view: this is a maintenance problem in the python packages themselves, caused by the general practice of pinning Regardless on your views on pinning, it's a problem in pip. A version conflict should be reported as an installation failure, not allow you to continue. And again, version restrictions will always be there. The "live at master" philosophy only works for small groups of similar output capacity. It won't work for an ecosystem as wide as Python. Even without version pinning, you'll still have packages breaking because another one was updated. Sometimes it will be necessary, such as for example a package dropping support for a feature that another one needs.
robertlagrant 5y ago
> Right, but then just use pip install --user instead of a virtualenv This seems almost as bad as system python. I suppose it's fine if you only work on one thing, but as soon as you don't, your dev environment will become chaotic and lots of confusing WFM will happen. E.g. this is why npm has a separate node_modules folder for each project.
- 1337shadow 5y ago
  > why npm has a separate node_modules folder for each project This sacrifies time and disk space and hides tech debt under the carpet, I'd rather have a solution like `pip upgrade` that would upgrade all packages and fix the environment, like `pacman -Syu`, but people would have to stop pinning versions and actually maintain their codebases and the dependencies they uses.
  - robertlagrant 5y ago
    > but people would have to stop pinning versions and actually maintain their codebases and the dependencies they uses Virtual environments is the mechanism by which you do that in a non-silly way. How do you think people cope with a dependency that has a bug introduced in the most recent version?

gjulianm 5y ago

I've run into problems when running pip install --user. Someone installs a package in the user environment, and that works. But later you'll install a package in a shared virtualenv (because a Python program needs to run as a service or by another users or whatever) and pip doesn't install it because it's already on the user environment. However, other users don't have access to that environment and they will have an import error that you won't see from your user. Not to mention that installing every dependency in the same environment is a recipe for both disaster with version conflicts and bloat when you don't really know which packages belong to which applications.

1337shadow 5y ago
Interesting problem but I think it's more a problem in virtualenv, which don't use global site package by default, I'm surprised that it uses user site packages by default. However, installing every dependency in the same environment is also what distro package managers do, I don't see that as a recipe for disaster, it all depends how well the said packages are maintained in which case just upgrading them should fix whatever problem.
- gjulianm 5y ago
  > However, installing every dependency in the same environment is also what distro package managers do, I don't see that as a recipe for disaster, Distro packages are done in a way where it's hard to get conflicts. I haven't found an instance where python3-X and python3-Y can't be installed because one requires python3-Z v1.2 and the other python3-Z v2.1. With Python packages, that happens way more often. Also, distro package managers keep track of everything installed, while python ones (at least pip I'm 100% sure) don't. You could install a package which upgrades another one, and that breaks another that you had installed before and pip won't say a word.
  - 1337shadow 5y ago
    > I haven't found an instance where python3-X and python3-Y can't be installed because one requires python3-Z v1.2 and the other python3-Z v2.1. With Python packages, that happens way more often. Exactly, because the packages were created/updated at a point in time were they were compatible: a distro ships python 3.x with packages of python modules that are compatible with python 3.x. Now if you as a user want to use a python package that works with python 3.y, you either have to wait, or install python 3.y, or use a container of python 3.y. Again, if all python package were up to date as in "working together at this point in time" then `pip upgrade` would work. > Also, distro package managers keep track of everything installed, while python ones (at least pip I'm 100% sure) don't. Are you sure you checked in the `*.dist-info` directories? There should be one per package, containing: a METADATA file, with all dependency versions, a RECORD file, with every installed file and their hash, and much more! see for yourself ;) > You could install a package which upgrades another one, and that breaks another that you had installed before and pip won't say a word. Let's agree to disagree right there: - in your point of view: this is a problem in pip - in my point of view: this is a maintenance problem in the python packages themselves, caused by the general practice of pinning
    - gjulianm 5y ago
      > Again, if all python package were up to date as in "working together at this point in time" then `pip upgrade` would work. That is impossible, it will never happen. Packages will have different maintenance cycles, some will get deprecated, others abandoned... You can't base your upgrade policy on an impossible situation. > Are you sure you checked in the `*.dist-info` directories? There should be one per package, containing: a METADATA file, with all dependency versions, a RECORD file, with every installed file and their hash, and much more! see for yourself ;) I know, but pip doesn't track all of those all the time. An example that has happened to me multiple times: install package X that depends on Y <= 1.0. Good, pip installs the proper version. Now, on another command, install package Z that depends on Y >= 2.0. Pip will install Y >= 2.0 and won't care that package X is now broken. > - in my point of view: this is a maintenance problem in the python packages themselves, caused by the general practice of pinning Regardless on your views on pinning, it's a problem in pip. A version conflict should be reported as an installation failure, not allow you to continue. And again, version restrictions will always be there. The "live at master" philosophy only works for small groups of similar output capacity. It won't work for an ecosystem as wide as Python. Even without version pinning, you'll still have packages breaking because another one was updated. Sometimes it will be necessary, such as for example a package dropping support for a feature that another one needs.

robertlagrant 5y ago

> Right, but then just use pip install --user instead of a virtualenv This seems almost as bad as system python. I suppose it's fine if you only work on one thing, but as soon as you don't, your dev environment will become chaotic and lots of confusing WFM will happen. E.g. this is why npm has a separate node_modules folder for each project.

1337shadow 5y ago
> why npm has a separate node_modules folder for each project This sacrifies time and disk space and hides tech debt under the carpet, I'd rather have a solution like `pip upgrade` that would upgrade all packages and fix the environment, like `pacman -Syu`, but people would have to stop pinning versions and actually maintain their codebases and the dependencies they uses.
- robertlagrant 5y ago
  > but people would have to stop pinning versions and actually maintain their codebases and the dependencies they uses Virtual environments is the mechanism by which you do that in a non-silly way. How do you think people cope with a dependency that has a bug introduced in the most recent version?