[legacy] root: Fix compilation with Python 3.11

cmake/legacy.cmake

@@ -347,6 +347,9 @@ ExternalProject_Add(root
   GIT_REPOSITORY https://github.com/root-project/root/ GIT_TAG v${root_version_gittag}
   GIT_SHALLOW 1
   PATCH_COMMAND ${patch} -p1 -i "${CMAKE_SOURCE_DIR}/legacy/root/fix_compilation_with_gcc12.patch"
+  COMMAND ${patch} -p1 -i "${CMAKE_SOURCE_DIR}/legacy/root/fix_pyroot_code_h_inclusion_python_3_11.patch"
+  COMMAND ${patch} -p1 -i "${CMAKE_SOURCE_DIR}/legacy/root/fix_tpython_python_3_11_deprecation.patch"
+  COMMAND ${patch} -p1 -i "${CMAKE_SOURCE_DIR}/legacy/root/fix_pyroot_cast_error_python_3_11.patch"
   ${CMAKE_DEFAULT_ARGS} CMAKE_ARGS
     "-Daqua=ON"
     "-Dasimage=ON"

legacy/root/fix_pyroot_cast_error_python_3_11.patch

@@ -0,0 +1,24 @@
+commit 98ad99126cd7f2754dc02ae7e82288d435fec341
+Author: Enric Tejedor Saavedra <enric.tejedor.saavedra@cern.ch>
+Date:   Fri Jun 10 16:42:49 2022 +0200
+
+    [PyROOT] Prevent cast error when calling PyTuple_SET_ITEM in 3.11
+
+    PyTuple_SET_ITEM ends up calling _PyObject_CAST(nullptr) which
+    causes "error: invalid cast from type 'std::nullptr_t' to type
+    'const PyObject*' {aka 'const _object*'}
+
+diff --git a/bindings/pyroot/cppyy/CPyCppyy/src/CPPMethod.cxx b/bindings/pyroot/cppyy/CPyCppyy/src/CPPMethod.cxx
+index 685ad3dc60..2189348594 100644
+--- a/bindings/pyroot/cppyy/CPyCppyy/src/CPPMethod.cxx
++++ b/bindings/pyroot/cppyy/CPyCppyy/src/CPPMethod.cxx
+@@ -580,7 +580,7 @@ PyObject* CPyCppyy::CPPMethod::ProcessKeywords(PyObject* self, PyObject* args, P
+ // set all values to zero to be able to check them later (this also guarantees normal
+ // cleanup by the tuple deallocation)
+     for (Py_ssize_t i = 0; i < nArgs+nKeys; ++i)
+-        PyTuple_SET_ITEM(newArgs, i, nullptr);
++        PyTuple_SET_ITEM(newArgs, i, static_cast<PyObject*>(nullptr));
+
+ // next, insert the keyword values
+     PyObject *key, *value;
+

legacy/root/fix_pyroot_code_h_inclusion_python_3_11.patch

@@ -0,0 +1,29 @@
+commit c861479d05885c2b8250ac03da96bacfe034d30a
+Author: Enric Tejedor Saavedra <enric.tejedor.saavedra@cern.ch>
+Date:   Thu Jun 9 12:24:07 2022 +0200
+
+    [PyROOT] code.h must not be included directly in 3.11
+
+    It has been moved to Include/cpython, and it is included by Python.h.
+
+    See:
+    https://docs.python.org/3.11/whatsnew/3.11.html
+
+diff --git a/bindings/pyroot/cppyy/CPyCppyy/src/CPPOverload.cxx b/bindings/pyroot/cppyy/CPyCppyy/src/CPPOverload.cxx
+index 146ca01389..97e557a1b2 100644
+--- a/bindings/pyroot/cppyy/CPyCppyy/src/CPPOverload.cxx
++++ b/bindings/pyroot/cppyy/CPyCppyy/src/CPPOverload.cxx
+@@ -1,10 +1,10 @@
+ // Bindings
+ #include "CPyCppyy.h"
+ #include "structmember.h"    // from Python
+-#if PY_VERSION_HEX >= 0x02050000
+-#include "code.h"            // from Python
+-#else
++#if PY_VERSION_HEX < 0x02050000
+ #include "compile.h"         // from Python
++#elif PY_VERSION_HEX < 0x030b0000
++#include "code.h"            // from Python
+ #endif
+ #ifndef CO_NOFREE
+ // python2.2 does not have CO_NOFREE defined

legacy/root/fix_tpython_python_3_11_deprecation.patch

@@ -0,0 +1,71 @@
+commit dc4e620480c77f8fc9b51075f28fa57413464fde
+Author: Enric Tejedor Saavedra <enric.tejedor.saavedra@cern.ch>
+Date:   Fri Jun 10 16:07:10 2022 +0200
+
+    [TPython] PySys_SetArgv is deprecated in 3.11
+
+    We should use the new PyConfig API of the Python Initialization
+    Configuration instead.
+
+    See:
+    https://docs.python.org/3.11/whatsnew/3.11.html#id7
+
+diff --git a/bindings/tpython/src/TPython.cxx b/bindings/tpython/src/TPython.cxx
+index 5cae95abbb..a98d1134e5 100644
+--- a/bindings/tpython/src/TPython.cxx
++++ b/bindings/tpython/src/TPython.cxx
+@@ -120,7 +120,37 @@ Bool_t TPython::Initialize()
+ #if PY_VERSION_HEX < 0x03020000
+       PyEval_InitThreads();
+ #endif
++
++// set the command line arguments on python's sys.argv
++#if PY_VERSION_HEX < 0x03000000
++      char *argv[] = {const_cast<char *>("root")};
++#else
++      wchar_t *argv[] = {const_cast<wchar_t *>(L"root")};
++#endif
++      int argc = sizeof(argv) / sizeof(argv[0]);
++#if PY_VERSION_HEX < 0x030b0000
+       Py_Initialize();
++#else
++      PyStatus status;
++      PyConfig config;
++
++      PyConfig_InitPythonConfig(&config);
++
++      status = PyConfig_SetArgv(&config, argc, argv);
++      if (PyStatus_Exception(status)) {
++         PyConfig_Clear(&config);
++         std::cerr << "Error when setting command line arguments." << std::endl;
++         return kFALSE;
++      }
++
++      status = Py_InitializeFromConfig(&config);
++      if (PyStatus_Exception(status)) {
++         PyConfig_Clear(&config);
++         std::cerr << "Error when initializing Python." << std::endl;
++         return kFALSE;
++      }
++      PyConfig_Clear(&config);
++#endif
+ #if PY_VERSION_HEX >= 0x03020000
+ #if PY_VERSION_HEX < 0x03090000
+       PyEval_InitThreads();
+@@ -134,13 +164,9 @@ Bool_t TPython::Initialize()
+          return kFALSE;
+       }
+
+-// set the command line arguments on python's sys.argv
+-#if PY_VERSION_HEX < 0x03000000
+-      char *argv[] = {const_cast<char *>("root")};
+-#else
+-      wchar_t *argv[] = {const_cast<wchar_t *>(L"root")};
++#if PY_VERSION_HEX < 0x030b0000
++      PySys_SetArgv(argc, argv);
+ #endif
+-      PySys_SetArgv(sizeof(argv) / sizeof(argv[0]), argv);
+
+       // force loading of the ROOT module
+       const int ret = PyRun_SimpleString(const_cast<char *>("import ROOT"));
+