From 75deb425c238d6c794a6a97b010f6fdf119a2dd7 Mon Sep 17 00:00:00 2001
From: Samuel Felton <samuel.felton@irisa.fr>
Date: Fri, 26 Jan 2024 12:49:34 +0100
Subject: [PATCH] tentative at improving system python rejection (avoid
 caching, still some issues with a base conda environment

---
 CMakeLists.txt                | 37 ++++++++++++++++++++++++++++++++++-
 modules/python/CMakeLists.txt | 17 ----------------
 2 files changed, 36 insertions(+), 18 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index c8d05d0775..465c151ef4 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -269,6 +269,27 @@ endif()
 
 # --- Python Support ---
 if(NOT IOS)
+  # Make sure to refresh the python interpreter every time we rerun cmake
+  # If we don't do this, we may use an old or invalid python when installing the bindings
+  # that was cached by a previous attempt at building
+
+
+  # # this avoids non-active conda from getting picked anyway on Windows
+  # set(Python_FIND_REGISTRY LAST)
+  # set(Python_FIND_VIRTUALENV FIRST)
+  # set(Python_FIND_STRATEGY LOCATION)
+  unset(PYTHON3INTERP_FOUND CACHE)
+  unset(PYTHONINTERP_FOUND CACHE)
+  unset(PYTHON3INTERP_FOUND)
+  unset(PYTHONLIBS_FOUND CACHE)
+  unset(PYTHONINTERP_FOUND)
+  unset(PYTHON_FOUND CACHE)
+  unset(PYTHON3_EXECUTABLE CACHE)
+  unset(PYTHON_EXECUTABLE CACHE)
+  unset(PYTHON3_EXECUTABLE)
+  unset(PYTHON_EXECUTABLE)
+  unset(VISP_PYTHON_IS_SYSTEM_WIDE CACHE)
+  unset(VISP_PYTHON3_VERSION CACHE)
   include(cmake/VISPDetectPython.cmake)
 endif()
 
@@ -279,10 +300,24 @@ else()
 endif()
 
 if(CMAKE_NOT_OK_FOR_BINDINGS)
-  status("${CMAKE_NOT_OK_FOR_BINDINGS}")
   status("CMake version required for Python bindings is 3.19.0, but you have ${CMAKE_VERSION}. Python bindings generation will be deactivated")
 endif()
 
+if(DEFINED ENV{VIRTUAL_ENV} OR DEFINED ENV{CONDA_PREFIX})
+  set(_pip_args)
+  set(VISP_PYTHON_IS_SYSTEM_WIDE FALSE)
+else()
+  # First solution: raise an error when cmake will call pip install
+  # set(_pip_args "--require-virtualenv") # If this is a system python, throw an error
+  message(WARNING "\
+  The python version that you are using (${PYTHON3_EXECUTABLE}) is the system interpreter.
+  pip packages should not be installed system-wide!
+  Python bindings targets will be deactivated!
+  To reenable them, install conda or virtualenv, delete the CMakeCache file then rerun cmake when inside the virtual environment.
+  ")
+  set(VISP_PYTHON_IS_SYSTEM_WIDE TRUE)
+endif()
+
 # --- Python Bindings requirements ---
 
 # this avoids non-active conda from getting picked anyway on Windows
diff --git a/modules/python/CMakeLists.txt b/modules/python/CMakeLists.txt
index 90e497a064..dd2035c473 100644
--- a/modules/python/CMakeLists.txt
+++ b/modules/python/CMakeLists.txt
@@ -44,23 +44,6 @@ find_package(VISP REQUIRED)
 
 # TODO: check for pip
 
-# Set pip args
-if(DEFINED ENV{VIRTUAL_ENV} OR DEFINED ENV{CONDA_PREFIX})
-  set(_pip_args)
-  set(VISP_PYTHON_IS_SYSTEM_WIDE FALSE PARENT_SCOPE)
-else()
-  # First solution: raise an error when cmake will call pip install
-  # set(_pip_args "--require-virtualenv") # If this is a system python, throw an error
-  message(WARNING "\
-  The python version that you are using (${PYTHON3_EXECUTABLE}) is the system interpreter.
-  pip packages should not be installed system-wide!
-  Python bindings targets will be deactivated!
-  To reenable them, install conda or virtualenv, delete the CMakeCache file then rerun cmake when inside the virtual environment.
-  ")
-  set(VISP_PYTHON_IS_SYSTEM_WIDE TRUE PARENT_SCOPE)
-  return()
-endif()
-
 # Step 1: Generate configuration file
 # Define modules for which to generate python bindings
 set(python_ignored_modules "visp_python" "visp_java_bindings_generator" "visp_java" )