python 3.13 blog

blog/2024-09-26-python-313.md

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+---
+authors:
+  - isuruf
+tags: [infrastructure]
+---
+
+# Python 3.13 Release candidate builds on conda-forge
+
+conda-forge now supports Python 3.13 release candidates on conda.
+You can create a new environment with Python 3.13 by running the
+command:
+
+    conda create -n py313 python=3.13 -c conda-forge/label/python_rc -c conda-forge
+
+<!-- truncate -->
+
+This will create a new environment with Python 3.13 with the global
+interpreter lock (GIL) enabled. A migration is underway that builds
+Python extensions like those included in `numpy` and `scipy` as conda packages. The migration
+is [55% complete](/status/migration/?name=python313) at the time of writing. Once the first final release of
+`python` 3.13 is available the `python_rc` label will not be needed
+anymore.
+
+New in this Python release is the `python-freethreading` build which
+removes the GIL and enables free threading. To install a `freethreading`
+build, you can do:
+
+    conda create -n py313 python=3.13 python-freethreading -c conda-forge/label/python_rc -c conda-forge
+
+Analogous to this package we also have a metapackage to explicitly
+install the GIL variant:
+
+    conda create -n py313 python=3.13 cpython-gil -c conda-forge/label/python_rc -c conda-forge
+
+Note that there are no conda packages for freethreading Python extensions yet and
+we hope to start a migration for freethreading extensions in the
+coming weeks. Till then, you should use `pip` to install a package
+unless the package and all its Python dependencies are `noarch` in which
+case conda installing the package will work.
+
+Another new feature of this release is the experimental just-in-time
+(JIT) compiler included in the Python interpreter. This interpreter is
+experimental, but can be used by setting the environment variable
+
+    export PYTHON_JIT=1
+
+You can also use the convenience conda package to set this environment
+variable for you:
+
+    conda install python-jit
+
+Note that the JIT is available only for `x86_64` builds of python in
+conda.
+
+You can also use debug builds of Python on conda-forge for non-Windows
+systems by using the `conda-forge/label/python_debug` label.
+
+Any issues with python conda package itself can be reported at [`python-feedstock`](https://github.com/conda-forge/python-feedstock).
+
+### Acknowledgements
+
+Thanks to Uwe Korn ([@xhochy](https://github.com/xhochy)) for getting us started
+and for Jonathan Helmus ([@jjhelmus](https://github.com/jjhelmus)) for guidance.
+Also thanks to conda-forge/core and all the maintainers of feedstocks in conda-forge
+for the hard work in getting the Python 3.13 migration underway.