From: =?utf-8?q?Timo_R=C3=B6hling?= <roehling@debian.org>
Date: Fri, 14 Oct 2022 11:59:04 +0200
Subject: Prefer Debian default version of Python

Forwarded: not-needed
---
 Modules/FindPython/Support.cmake | 20 ++++++++++++++++++++
 Modules/FindPythonInterp.cmake   | 20 ++++++++++++++++++++
 Modules/FindPythonLibs.cmake     | 20 ++++++++++++++++++++
 3 files changed, 60 insertions(+)

diff --git a/Modules/FindPython/Support.cmake b/Modules/FindPython/Support.cmake
index c4fae6b..3e4279e 100644
--- a/Modules/FindPython/Support.cmake
+++ b/Modules/FindPython/Support.cmake
@@ -23,6 +23,26 @@ if (NOT DEFINED _${_PYTHON_PREFIX}_REQUIRED_VERSION_MAJOR)
 endif()
 if (_${_PYTHON_PREFIX}_REQUIRED_VERSION_MAJOR EQUAL "3")
   set(_${_PYTHON_PREFIX}_VERSIONS 3.12 3.11 3.10 3.9 3.8 3.7 3.6 3.5 3.4 3.3 3.2 3.1 3.0)
+  # Debian-specific: prefer current default version
+  if(NOT DEFINED PYTHON3_DEBIAN_DEFAULT_VERSION)
+      execute_process(
+          COMMAND py3versions -vd
+          OUTPUT_VARIABLE _PYTHON3_DEFAULT_VERSION
+          RESULT_VARIABLE _PYTHON3_DEFAULT_RESULT
+          OUTPUT_STRIP_TRAILING_WHITESPACE
+          ERROR_QUIET
+      )
+      if(_PYTHON3_DEFAULT_RESULT EQUAL "0")
+          set(PYTHON3_DEBIAN_DEFAULT_VERSION "${_PYTHON3_DEFAULT_VERSION}" CACHE INTERNAL "Current Python 3 default version in Debian")
+      endif()
+      unset(_PYTHON3_DEFAULT_VERSION)
+      unset(_PYTHON3_DEFAULT_RESULT)
+  endif()
+  if(DEFINED PYTHON3_DEBIAN_DEFAULT_VERSION)
+      list(REMOVE_ITEM _${_PYTHON_PREFIX}_VERSIONS ${PYTHON3_DEBIAN_DEFAULT_VERSION})
+      list(INSERT _${_PYTHON_PREFIX}_VERSIONS 0 ${PYTHON3_DEBIAN_DEFAULT_VERSION})
+  endif()
+  # End of Debian-specific code
 elseif (_${_PYTHON_PREFIX}_REQUIRED_VERSION_MAJOR EQUAL "2")
   set(_${_PYTHON_PREFIX}_VERSIONS 2.7 2.6 2.5 2.4 2.3 2.2 2.1 2.0)
 else()
diff --git a/Modules/FindPythonInterp.cmake b/Modules/FindPythonInterp.cmake
index 7ad3587..d6e41b0 100644
--- a/Modules/FindPythonInterp.cmake
+++ b/Modules/FindPythonInterp.cmake
@@ -76,6 +76,26 @@ if(PythonInterp_FIND_VERSION)
         set(_PYTHON_FIND_OTHER_VERSIONS ${_PYTHON${PythonInterp_FIND_VERSION_MAJOR}_VERSIONS})
     endif()
 else()
+    # Debian-specific: prefer current default version
+    if(NOT DEFINED PYTHON3_DEBIAN_DEFAULT_VERSION)
+        execute_process(
+            COMMAND py3versions -vd
+            OUTPUT_VARIABLE _PYTHON3_DEFAULT_VERSION
+            RESULT_VARIABLE _PYTHON3_DEFAULT_RESULT
+            OUTPUT_STRIP_TRAILING_WHITESPACE
+            ERROR_QUIET
+        )
+        if(_PYTHON3_DEFAULT_RESULT EQUAL "0")
+            set(PYTHON3_DEBIAN_DEFAULT_VERSION "${_PYTHON3_DEFAULT_VERSION}" CACHE INTERNAL "Current Python 3 default version in Debian")
+        endif()
+        unset(_PYTHON3_DEFAULT_VERSION)
+        unset(_PYTHON3_DEFAULT_RESULT)
+    endif()
+    if(DEFINED PYTHON3_DEBIAN_DEFAULT_VERSION)
+        list(REMOVE_ITEM _PYTHON3_VERSIONS ${PYTHON3_DEBIAN_DEFAULT_VERSION})
+        list(INSERT _PYTHON3_VERSIONS 0 ${PYTHON3_DEBIAN_DEFAULT_VERSION})
+    endif()
+    # End of Debian-specific code
     set(_PYTHON_FIND_OTHER_VERSIONS ${_PYTHON3_VERSIONS} ${_PYTHON2_VERSIONS} ${_PYTHON1_VERSIONS})
 endif()
 find_program(PYTHON_EXECUTABLE NAMES ${_Python_NAMES})
diff --git a/Modules/FindPythonLibs.cmake b/Modules/FindPythonLibs.cmake
index 43a84dd..8bf2015 100644
--- a/Modules/FindPythonLibs.cmake
+++ b/Modules/FindPythonLibs.cmake
@@ -103,6 +103,26 @@ if(PythonLibs_FIND_VERSION)
         set(_PYTHON_FIND_OTHER_VERSIONS ${_PYTHON${PythonLibs_FIND_VERSION_MAJOR}_VERSIONS})
     endif()
 else()
+    # Debian-specific: prefer current default version
+    if(NOT DEFINED PYTHON3_DEBIAN_DEFAULT_VERSION)
+        execute_process(
+            COMMAND py3versions -vd
+            OUTPUT_VARIABLE _PYTHON3_DEFAULT_VERSION
+            RESULT_VARIABLE _PYTHON3_DEFAULT_RESULT
+            OUTPUT_STRIP_TRAILING_WHITESPACE
+            ERROR_QUIET
+        )
+        if(_PYTHON3_DEFAULT_RESULT EQUAL "0")
+            set(PYTHON3_DEBIAN_DEFAULT_VERSION "${_PYTHON3_DEFAULT_VERSION}" CACHE INTERNAL "Current Python 3 default version in Debian")
+        endif()
+        unset(_PYTHON3_DEFAULT_VERSION)
+        unset(_PYTHON3_DEFAULT_RESULT)
+    endif()
+    if(DEFINED PYTHON3_DEBIAN_DEFAULT_VERSION)
+        list(REMOVE_ITEM _PYTHON3_VERSIONS ${PYTHON3_DEBIAN_DEFAULT_VERSION})
+        list(INSERT _PYTHON3_VERSIONS 0 ${PYTHON3_DEBIAN_DEFAULT_VERSION})
+    endif()
+    # End of Debian-specific code
     set(_PYTHON_FIND_OTHER_VERSIONS ${_PYTHON3_VERSIONS} ${_PYTHON2_VERSIONS} ${_PYTHON1_VERSIONS})
 endif()