From 40f821a52a6fbda0b67ab6460cc644e44250f07e Mon Sep 17 00:00:00 2001
From: Miro Hrončok <miro@hroncok.cz>
Date: Jan 19 2022 14:51:47 +0000
Subject: Python: Add a warning about git tarballs and setuptools_scm


---

diff --git a/guidelines/modules/ROOT/pages/Python.adoc b/guidelines/modules/ROOT/pages/Python.adoc
index 0cb0c12..5768573 100644
--- a/guidelines/modules/ROOT/pages/Python.adoc
+++ b/guidelines/modules/ROOT/pages/Python.adoc
@@ -1136,6 +1136,20 @@ When using sources from PyPI,
 you can use the <<pypi_source,the `+%pypi_source+` macro>>
 to generate the proper URL.
 
+WARNING: Some Python packages use metadata from `git`
+(or a similar version control system)
+to construct their version string,
+for example via https://pypi.org/project/setuptools-scm/[setuptools_scm].
+When publishing a package to PyPI,
+this version metadata is usually stored and included in a file,
+so the version control history is no longer needed to construct it.
+However, when using tarballs from a git forge directly,
+this version information is missing
+and must be manually provided by the packager.
+For example, the `SETUPTOOLS_SCM_PRETEND_VERSION` environment variable can be set
+to the desired value in the `+%generate_buildrequires+` and `+%build+` scripts in the spec file
+for packages that use `setuptools_scm` for this purpose.
+
 == Example spec file[[_example_python_spec_file]]
 
 The following is a viable spec file