Create target directory structure in installation folder

This allows removing the extra RPATH manipulations in our CPython extensions

Author: vepadulano

bindings/pyroot/cppyy/CPyCppyy/CMakeLists.txt

@@ -54,18 +54,6 @@ set(libname cppyy)
 add_library(${libname} SHARED ${headers} ${sources})
 # Set the suffix to '.so' and the prefix to 'lib'
 set_target_properties(${libname} PROPERTIES  ${ROOT_LIBRARY_PROPERTIES})
-# It is crucial to add the path to the other ROOT libraries for compatibility with pip build backends.
-# After the `pip install` step, the target install user directory will look like:
-# site-packages/
-# -- cppyy/
-# -- cppyy_backend/
-# -- libcppyy.so
-# -- libcppyy_backend.so
-# -- libROOTPythonizations.so
-# -- ROOT/
-# With most of the ROOT libraries being stored in `ROOT/lib`. The RPATH must then be updated for the CPython extension
-# shared libraries.
-set_target_properties(${libname} PROPERTIES  INSTALL_RPATH "${CMAKE_INSTALL_RPATH}:$ORIGIN/ROOT/lib")
 if(MSVC)
   target_link_libraries(${libname} PUBLIC cppyy_backend Python3::Python)
   set_target_properties(${libname} PROPERTIES WINDOWS_EXPORT_ALL_SYMBOLS TRUE)

bindings/pyroot/cppyy/cppyy-backend/CMakeLists.txt

@@ -31,25 +31,13 @@ if(MSVC)
 endif()
 # Set the suffix to '.so' and the prefix to 'lib'
 set_target_properties(${libname} PROPERTIES  ${ROOT_LIBRARY_PROPERTIES})
-
 target_link_libraries(${libname} Core ${CMAKE_DL_LIBS})
 
 # cppyy uses ROOT headers from binary directory
 add_dependencies(${libname} move_headers)
 
 set_property(GLOBAL APPEND PROPERTY ROOT_EXPORTED_TARGETS ${libname})
 
-# It is crucial to add the path to the other ROOT libraries for compatibility with pip build backends.
-# After the `pip install` step, the target install user directory will look like:
-# site-packages/
-# -- cppyy/
-# -- cppyy_backend/
-# -- libcppyy.so
-# -- libcppyy_backend.so
-# -- libROOTPythonizations.so
-# -- ROOT/
-# With most of the ROOT libraries being stored in `ROOT/lib`. The RPATH must then be updated for the CPython extension
-# shared libraries.
 if(NOT MSVC)
   # Make sure that relative RUNPATH to main ROOT libraries is always correct.
 
@@ -64,8 +52,7 @@ if(NOT MSVC)
   else()
     set_target_properties(${libname} PROPERTIES
         BUILD_RPATH "$ORIGIN/${pymoduledir_to_libdir_build}"
-        # ATTENTION: CRUCIAL! See comment above
-        INSTALL_RPATH "$ORIGIN/${pymoduledir_to_libdir_install}:${CMAKE_INSTALL_RPATH}:$ORIGIN/ROOT/lib"
+        INSTALL_RPATH "$ORIGIN/${pymoduledir_to_libdir_install}"
     )
   endif()
 

bindings/pyroot/pythonizations/CMakeLists.txt

@@ -174,7 +174,7 @@ add_dependencies(${libname} ROOTPythonizationsPySources)
 
 # Set the suffix to '.so' and the prefix to 'lib'
 set_target_properties(${libname} PROPERTIES ${ROOT_LIBRARY_PROPERTIES_NO_VERSION})
-target_link_libraries(${libname} PUBLIC ROOT::Core ROOT::Tree cppyy)
+target_link_libraries(${libname} PUBLIC Core Tree cppyy)
 if(MSVC)
   set_target_properties(${libname} PROPERTIES WINDOWS_EXPORT_ALL_SYMBOLS TRUE)
   set_target_properties(${libname} PROPERTIES SUFFIX ".pyd")
@@ -228,18 +228,6 @@ else()
       LIBRARY_OUTPUT_DIRECTORY ${pymoduledir_build})
 endif()
 
-# It is crucial to add the path to the other ROOT libraries for compatibility with pip build backends.
-# After the `pip install` step, the target install user directory will look like:
-# site-packages/
-# -- cppyy/
-# -- cppyy_backend/
-# -- libcppyy.so
-# -- libcppyy_backend.so
-# -- ROOT/
-# -- -- libROOTPythonizations.so
-# With most of the ROOT libraries being stored in `ROOT/lib`. The RPATH must then be updated for the CPython extension
-# shared libraries.
-
 if(NOT MSVC)
   # Make sure that relative RUNPATH to main ROOT libraries is always correct.
 
@@ -254,8 +242,7 @@ if(NOT MSVC)
   else()
     set_target_properties(${libname} PROPERTIES
         BUILD_RPATH "$ORIGIN/${pymoduledir_to_libdir_build}"
-        # ATTENTION: NEXT PART IS CRUCIAL SEE COMMENT ABOVE
-        INSTALL_RPATH "$ORIGIN/${pymoduledir_to_libdir_install}:${CMAKE_INSTALL_RPATH}:$ORIGIN/lib"
+        INSTALL_RPATH "$ORIGIN/${pymoduledir_to_libdir_install}"
     )
   endif()
 

setup.py

@@ -36,6 +36,11 @@
 BUILD_DIR = tempfile.mkdtemp()
 INSTALL_DIR = tempfile.mkdtemp()
 
+# Name given to an internal directory within the build directory
+# used to mimick the structure of the target installation directory
+# in the user Python environment, usually named "site-packages"
+ROOT_BUILD_INTERNAL_DIRNAME = "mock_site_packages"
+
 
 class ROOTBuild(_build):
     def run(self):
@@ -50,6 +55,12 @@ def run(self):
             "-Dbuiltin_lz4=ON -Dbuiltin_lzma=ON -Dbuiltin_zstd=ON -Dbuiltin_xxhash=ON "  # builtins
             "-Dpyroot=ON -Ddataframe=ON -Dxrootd=ON -Dssl=ON -Dimt=ON "
             "-Droofit=ON "
+            # Next 4 paths represent the structure of the target binaries/headers/libs
+            # as the target installation directory of the Python environment would expect
+            f"-DCMAKE_INSTALL_BINDIR={ROOT_BUILD_INTERNAL_DIRNAME}/ROOT/bin "
+            f"-DCMAKE_INSTALL_INCLUDEDIR={ROOT_BUILD_INTERNAL_DIRNAME}/ROOT/include "
+            f"-DCMAKE_INSTALL_LIBDIR={ROOT_BUILD_INTERNAL_DIRNAME}/ROOT/lib "
+            f"-DCMAKE_INSTALL_PYTHONDIR={ROOT_BUILD_INTERNAL_DIRNAME} "
             f"-DCMAKE_INSTALL_PREFIX={INSTALL_DIR} -B {BUILD_DIR} -S {SOURCE_DIR}"
         )
         subprocess.run(configure_command, check=True)
@@ -79,16 +90,22 @@ def run(self):
         lib_dir = os.path.join(INSTALL_DIR, "lib")
 
         # Copy ROOT installation tree to the ROOT package directory in the pip installation path
-        self.copy_tree(INSTALL_DIR, os.path.join(install_path, "ROOT"))
-
-        # Copy cppyy packages separately
-        self.copy_tree(os.path.join(lib_dir, "cppyy"), os.path.join(install_path, "cppyy"))
-        self.copy_tree(os.path.join(lib_dir, "cppyy_backend"), os.path.join(install_path, "cppyy_backend"))
-
-        # Finally copy CPython extension libraries
-        self.copy_file(os.path.join(lib_dir, "libcppyy.so"), install_path)
-        self.copy_file(os.path.join(lib_dir, "libcppyy_backend.so"), install_path)
-        self.copy_file(os.path.join(lib_dir, "ROOT", "libROOTPythonizations.so"), os.path.join(install_path, "ROOT"))
+        self.copy_tree(os.path.join(INSTALL_DIR, ROOT_BUILD_INTERNAL_DIRNAME), install_path)
+
+        root_package_dir = os.path.join(install_path, "ROOT")
+
+        # After the copy of the "mock" package structure from the ROOT installations, these are the
+        # leftover directories that still need to be copied
+        self.copy_tree(os.path.join(INSTALL_DIR, "cmake"), os.path.join(root_package_dir, "cmake"))
+        self.copy_tree(os.path.join(INSTALL_DIR, "config"), os.path.join(root_package_dir, "config"))
+        self.copy_tree(os.path.join(INSTALL_DIR, "etc"), os.path.join(root_package_dir, "etc"))
+        self.copy_tree(os.path.join(INSTALL_DIR, "fonts"), os.path.join(root_package_dir, "fonts"))
+        self.copy_tree(os.path.join(INSTALL_DIR, "icons"), os.path.join(root_package_dir, "icons"))
+        self.copy_tree(os.path.join(INSTALL_DIR, "macros"), os.path.join(root_package_dir, "macros"))
+        self.copy_tree(os.path.join(INSTALL_DIR, "man"), os.path.join(root_package_dir, "man"))
+        self.copy_tree(os.path.join(INSTALL_DIR, "README"), os.path.join(root_package_dir, "README"))
+        self.copy_tree(os.path.join(INSTALL_DIR, "tutorials"), os.path.join(root_package_dir, "tutorials"))
+        self.copy_file(os.path.join(INSTALL_DIR, "LICENSE"), os.path.join(root_package_dir, "LICENSE"))
 
     def get_outputs(self):
         outputs = _install.get_outputs(self)