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Date: Sat, 19 Sep 2026 21:41:27 +0200
From: Maximiliano Curia <maxy@debian.org>
To: submit@bugs.debian.org
Subject: pandas: FTBFS against python 3.15rc2 as default
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Package: src:pandas
Version: 2.3.3+dfsg-5
User: debian-python@lists.debian.org
Usertags: python3.15-default
Tags: patch, ftbfs, forky, sid
Severity: important

Hi!

While rebuilding the python related packages against the Python 3.15rc2
as the default version we found that pandas failed to build from source
[1].

The problem is caused by packages that are used as test or documentation
dependencies, that depend on pandas. And these circular dependencies
fail, because pandas-lib depends on Python3 < 3.15

I understand that this is a known problem, as the debian/control file
includes comments about this:

```
    # these are for not having (as many) exception messages in documentation examples
    # so may be temporarily removed if they are broken or to break bootstrap cycles
                      python3-rpy2 <!nodoc>,
                      python3-seaborn <!nodoc>,
    # these are also used in some tests, but depend on pandas, so are in -indep to avoid
    # circular-dependency BD-Uninstallable when arch:all finishes before some of the arch:any start
                      python3-pyreadstat (>= 1.2.8~) <!nocheck> <!nodoc>,
                      python3-statsmodels <!nocheck> <!nodoc>,
                      python3-xarray (>= 2024.10.0~) <!nocheck> <!nodoc>,
```

My suggestion to properly solve this rather than temporarily removing
the dependencies as the comment suggest, is to split the source package
in two: pandas on one side, and pandas-doc on the other. And move the
tests that cause circular dependencies to autopkg tests rather than
build tests.

Please consider applying a fix similar to this to avoid having to remove
this dependencies whenever the default Python version changes.

Setting the severity to important for now. Once Python 3.15 becomes the
default version this bug will become release critical.

Happy hacking,

[1]: https://debusine.debian.net/debian/r-python-python3.15/artifact/4749196/

-- 
"Can you imagine what I would do if I could do all I can?" -- Sun Tzu
Saludos /\/\ /\ >< `/
]