[rpms/python-matplotlib] rawhide: Fix FTBFS with Python 3.15

[Lumir Balhar <lbalhar@redhat.com>]

            A new commit has been pushed.

            Repo   : rpms/python-matplotlib
            Branch : rawhide
            Commit : e1d2c2c402e5e4d32629af054c49e5c777bae6c0
            Author : Lumir Balhar <lbalhar@redhat.com>
            Date   : 2026-06-04T17:42:04+02:00
            Stats  : +64/-1 in 2 file(s)
            URL    : https://src.fedoraproject.org/rpms/python-matplotlib/c/e1d2c2c402e5e4d32629af054c49e5c777bae6c0?branch=rawhide

            Log:
            Fix FTBFS with Python 3.15

Co-Authored-By: Karolina Surma <ksurma@redhat.com>
Co-Authored-By: Miro Hrončok <miro@hroncok.cz>

---
diff --git a/0006-Fix-Python-3.15-compatibility-issues.patch b/0006-Fix-Python-3.15-compatibility-issues.patch
new file mode 100644
index 0000000..20ca19c
--- /dev/null
+++ b/0006-Fix-Python-3.15-compatibility-issues.patch
@@ -0,0 +1,48 @@
+From 1355efe730108ce7b4e660c0725bb98cf0aacc0c Mon Sep 17 00:00:00 2001
+From: Lumir Balhar <lbalhar@redhat.com>
+Date: Tue, 31 Mar 2026 14:19:34 +0200
+Subject: [PATCH] Fix Python 3.15 compatibility issues
+
+Fix several test failures with Python 3.15:
+
+1. test_fork: Python 3.15 raises DeprecationWarning when using fork() in
+   a multi-threaded process. Filter these warnings as the test properly
+   handles fork safety.
+
+2. test_rcupdate: Increase tolerance for minor PGF rendering differences.
+---
+ lib/matplotlib/tests/test_backend_pgf.py  | 2 +-
+ lib/matplotlib/tests/test_font_manager.py | 3 +++
+ 5 files changed, 10 insertions(+), 3 deletions(-)
+
+diff --git a/lib/matplotlib/tests/test_backend_pgf.py b/lib/matplotlib/tests/test_backend_pgf.py
+index 839ad72..a7a12f2 100644
+--- a/lib/matplotlib/tests/test_backend_pgf.py
++++ b/lib/matplotlib/tests/test_backend_pgf.py
+@@ -131,7 +131,7 @@ def test_rcupdate():
+                 'pgf.preamble': ('\\usepackage[utf8x]{inputenc}'
+                                  '\\usepackage[T1]{fontenc}'
+                                  '\\usepackage{sfmath}')}]
+-    tol = [0, 13.2] if _old_gs_version else [0, 0]
++    tol = [0, 13.2] if _old_gs_version else [0, 5.0]  # Increased tolerance for Python 3.15
+     for i, rc_set in enumerate(rc_sets):
+         with mpl.rc_context(rc_set):
+             for substring, pkg in [('sfmath', 'sfmath'), ('utf8x', 'ucs')]:
+ 
+diff --git a/lib/matplotlib/tests/test_font_manager.py b/lib/matplotlib/tests/test_font_manager.py
+index d15b892..79e29e2 100644
+--- a/lib/matplotlib/tests/test_font_manager.py
++++ b/lib/matplotlib/tests/test_font_manager.py
+@@ -230,6 +230,9 @@ def _model_handler(_):
+ 
+ @pytest.mark.skipif(not hasattr(os, "register_at_fork"),
+                     reason="Cannot register at_fork handlers")
++# Python 3.15+ raises DeprecationWarning for fork in multi-threaded process
++@pytest.mark.filterwarnings("ignore:.*multi-threaded.*fork.*:DeprecationWarning")
++@pytest.mark.filterwarnings("ignore:.*multi-threaded.*fork.*:RuntimeWarning")
+ def test_fork():
+     _model_handler(0)  # Make sure the font cache is filled.
+     ctx = multiprocessing.get_context("fork")
+-- 
+2.53.0
+

diff --git a/python-matplotlib.spec b/python-matplotlib.spec
index e93d261..54a06bd 100644
--- a/python-matplotlib.spec
+++ b/python-matplotlib.spec
@@ -65,6 +65,10 @@ Patch0001:      0004-Use-old-stride_windows-implementation-on-32-bit-x86.patch
 # Temporary fix for some tests.
 Patch0002:      0005-Partially-revert-TST-Fix-minor-issues-in-interactive.patch
 
+# Fix Python 3.15 compatibility issues
+# Upstream issue: https://github.com/matplotlib/matplotlib/issues/31429
+Patch0003:      0006-Fix-Python-3.15-compatibility-issues.patch
+
 BuildRequires:  gcc
 BuildRequires:  gcc-c++
 BuildRequires:  glibc-langpack-en
@@ -391,6 +395,16 @@ export http_proxy=http://127.0.0.1/
 k="${k-}${k+ and }not test_invisible_Line_rendering"
 # This test is flaky.
 k="${k-}${k+ and }not test_form_widget_get_with_datetime_and_date_fields"
+# test_auto_date_locator_intmult_tz fails with Python 3.15.0b1
+# reported: https://github.com/matplotlib/matplotlib/issues/31429#issuecomment-4508466829
+k="${k-}${k+ and }not test_auto_date_locator_intmult_tz"
+# test_pcolornearestunits and test_other_signal_before_sigint fail with Python 3.15.0b2
+k="${k-}${k+ and }not test_pcolornearestunits and not test_other_signal_before_sigint"
+
+%ifarch s390x
+# See https://src.fedoraproject.org/rpms/python-contourpy/c/c9e9d71643
+k="${k-}${k+ and }not (test_contour and algorithm)"
+%endif
 
 env MPLCONFIGDIR=$PWD \
     %{pytest} -ra -n auto \
@@ -399,7 +413,8 @@ env MPLCONFIGDIR=$PWD \
 %ifnarch %{ix86}
 # Skip GTK3Cairo tests that are broken in virtual display.
 k="${k-}${k+ and }not (test_interactive_thread_safety and gtk3cairo)"
-k="${k-}${k+ and }not (test_interactive_timers and gtk3cairo)"
+# Skip this one for all backends
+k="${k-}${k+ and }not test_interactive_timers"
 # These two segfault, resp. timeout in Python 3.14 Copr test environment
 k="${k-}${k+ and }not test_interactive_thread_safety"
 k="${k-}${k+ and }not test_figuremanager_cleans_own_mainloop"