Python: Difference between revisions
imported>Phiadaarr m (Add missing "}") |
Widlarizer (talk | contribs) (Order matters in the case of multiple python3.withPackages) |
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'''Ultimately, it is up to your use case to determine if you need an optimized version of the Python interpreter. We encourage you to benchmark and test your code to determine if this is something that would benefit you.''' | '''Ultimately, it is up to your use case to determine if you need an optimized version of the Python interpreter. We encourage you to benchmark and test your code to determine if this is something that would benefit you.''' | ||
== | == Troubleshooting == | ||
=== My module cannot be imported === | === My module cannot be imported === | ||
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First, make sure that you installed/added your module to python. Typically you would use something like <code> (python3.withPackages (ps: with ps; [ yourmodule ]))</code> in the list of installed applications. | First, make sure that you installed/added your module to python. Typically you would use something like <code> (python3.withPackages (ps: with ps; [ yourmodule ]))</code> in the list of installed applications. | ||
It is also still possible (e.g. when using nix-shell) that you aren't using the python interpreter you want because another package provides its own <code>python3.withPackages</code> in buildInputs, for example, yosys. In this case, you should either include that package (or all needed packages) in your withPackages list to only have a single Python interpreter. Or you can change the order of your packages, such that the <code>python3.withPackages</code> comes first, and becomes the Python interpreter that you get. | |||
If you packaged yourself your application, make sure to use <code>buildPythonPackage</code> and **not** <code>buildPythonApplication</code> or <code>stdenv.mkDerivation</code>. The reason is that <code>python3.withPackages</code> [https://github.com/NixOS/nixpkgs/blob/91d1eb9f2a9c4e3c9d68a59f6c0cada8c63d5340/pkgs/top-level/python-packages.nix#L57 filters] the packages to check that they are built using the appropriate python interpreter: this is done by verifying that the derivation has a <code>pythonModule</code> attribute and only buildPythonPackage [https://github.com/NixOS/nixpkgs/blob/91d1eb9f2a9c4e3c9d68a59f6c0cada8c63d5340/pkgs/top-level/python-packages.nix#L43 sets this value] (passthru [https://github.com/NixOS/nixpkgs/blob/91d1eb9f2a9c4e3c9d68a59f6c0cada8c63d5340/pkgs/top-level/python-packages.nix#L75 here]) thanks to, notably <code>passthru = { pythonModule = python; }</code>. If you used <code>stdenv.mkDerivation</code> then you can maybe set this value manually, but it's safer to simply use <code>buildPythonPackage {format = "other"; … your derivation …}</code> instead of <code>mkDerivation</code>. | |||
== See also == | == See also == | ||