From 9b5935c61603cd8b296b3f9eccbefe99647466ff Mon Sep 17 00:00:00 2001
From: Robert Haschke <rhaschke@techfak.uni-bielefeld.de>
Date: Sat, 16 Oct 2021 20:47:03 +0200
Subject: [PATCH 1/2] Fix handling of multiple namespaced python packages in
 devel space

If there are multiple packages to be installed below a common namespace, only the last one installed is found in devel space,
because the path extension is always overwritten.
This PR augments the existing __extended_path.
---
 cmake/catkin_python_setup.cmake | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/cmake/catkin_python_setup.cmake b/cmake/catkin_python_setup.cmake
index e360706f3..d0f6ca163 100644
--- a/cmake/catkin_python_setup.cmake
+++ b/cmake/catkin_python_setup.cmake
@@ -80,11 +80,17 @@ function(catkin_python_setup)
       if(NOT ("${pkg}" STREQUAL "${name}"))
         message(FATAL_ERROR "The package name '${pkg}' differs from the basename of the path '${pkg_dir}' in project '${PROJECT_NAME}'")
       endif()
+      # Retrieve PACKAGE_PYTHONPATH from existing __init__.py
+      set(target_init_file ${CATKIN_DEVEL_PREFIX}/${PYTHON_INSTALL_DIR}/${pkg}/__init__.py)
+      if(EXISTS ${target_init_file})
+        file(READ ${target_init_file} file_content)
+        string(REGEX MATCH "__extended_path *= *'(.*)'\\.split" _ "${file_content}")
+        set(PACKAGE_PYTHONPATH ${CMAKE_MATCH_1})
+      endif()
+      # Extend PACKAGE_PYTHONPATH with current pkg's path
       get_filename_component(path ${pkg_dir} PATH)
-      set(PACKAGE_PYTHONPATH ${CMAKE_CURRENT_SOURCE_DIR}/${path})
-      configure_file(${catkin_EXTRAS_DIR}/templates/__init__.py.in
-        ${CATKIN_DEVEL_PREFIX}/${PYTHON_INSTALL_DIR}/${pkg}/__init__.py
-        @ONLY)
+      list(APPEND PACKAGE_PYTHONPATH ${CMAKE_CURRENT_SOURCE_DIR}/${path})
+      configure_file(${catkin_EXTRAS_DIR}/templates/__init__.py.in ${target_init_file} @ONLY)
     endforeach()
   endif()
 

From 9b2c06f10595b2f5ff0eda201e9c3fe6705c42d8 Mon Sep 17 00:00:00 2001
From: Robert Haschke <rhaschke@techfak.uni-bielefeld.de>
Date: Thu, 21 Oct 2021 17:00:29 +0200
Subject: [PATCH 2/2] Avoid adding duplicates

---
 cmake/catkin_python_setup.cmake | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/cmake/catkin_python_setup.cmake b/cmake/catkin_python_setup.cmake
index d0f6ca163..2880d752f 100644
--- a/cmake/catkin_python_setup.cmake
+++ b/cmake/catkin_python_setup.cmake
@@ -89,7 +89,7 @@ function(catkin_python_setup)
       endif()
       # Extend PACKAGE_PYTHONPATH with current pkg's path
       get_filename_component(path ${pkg_dir} PATH)
-      list(APPEND PACKAGE_PYTHONPATH ${CMAKE_CURRENT_SOURCE_DIR}/${path})
+      list_append_deduplicate(PACKAGE_PYTHONPATH ${CMAKE_CURRENT_SOURCE_DIR}/${path})
       configure_file(${catkin_EXTRAS_DIR}/templates/__init__.py.in ${target_init_file} @ONLY)
     endforeach()
   endif()