root-project · guitargeek · Apr 4, 2025 · Mar 31, 2025
@@ -527,6 +527,13 @@ PyObject* VectorData(PyObject* self, PyObject*)
 }
 
 
+// This function implements __array__, added to std::vector python proxies and causes
+// a bug (see explanation at Utility::AddToClass(pyclass, "__array__"...) in CPyCppyy::Pythonize)
+// The recursive nature of this function, passes each subarray (pydata) to the next call and only
+// the final buffer is cast to a lowlevel view and resized (in VectorData), resulting in only the
+// first 1D array to be returned. See https://github.com/root-project/root/issues/17729
+// It is temporarily removed to prevent errors due to -Wunused-function, since it is no longer added.
+#if 0
 //---------------------------------------------------------------------------
 PyObject* VectorArray(PyObject* self, PyObject* /* args */)
 {
@@ -535,7 +542,7 @@ PyObject* VectorArray(PyObject* self, PyObject* /* args */)
     Py_DECREF(pydata);
     return view;
 }
-
+#endif
 
 //-----------------------------------------------------------------------------
 static PyObject* vector_iter(PyObject* v) {
@@ -1810,9 +1817,15 @@ bool CPyCppyy::Pythonize(PyObject* pyclass, const std::string& name)
             Utility::AddToClass(pyclass, "__real_data", "data");
             Utility::AddToClass(pyclass, "data", (PyCFunction)VectorData);
 
+        // The addition of the __array__ utility to std::vector Python proxies causes a
+        // bug where the resulting array is a single dimension, causing loss of data when
+        // converting to numpy arrays, for >1dim vectors. Since this C++ pythonization
+        // was added with the upgrade in 6.32, and is only defined and used recursively,
+        // the safe option is to disable this function and no longer add it.
+#if 0
         // numpy array conversion
             Utility::AddToClass(pyclass, "__array__", (PyCFunction)VectorArray);
-
+#endif
         // checked getitem
             if (HasAttrDirect(pyclass, PyStrings::gLen)) {
                 Utility::AddToClass(pyclass, "_getitem__unchecked", "__getitem__");

@@ -0,0 +1,65 @@
+From 82295e09c77ae61e2fd8356be792d61addf2c801 Mon Sep 17 00:00:00 2001
+From: Aaron Jomy <aaronjomyjoseph@gmail.com>
+Date: Mon, 31 Mar 2025 14:27:32 +0200
+Subject: [PATCH] [CPyCppyy] Drop `__array__` from std::vector pythonizations
+
+The addition of the __array__ utility to std::vector Python proxies causes a
+bug where the resulting array is a single dimension, causing loss of data when
+converting to numpy arrays, for >1dim vectors. The recursive nature of this
+function, passes each subarray (pydata) to the next call and only the final
+buffer is cast to a lowlevel view and resized (in VectorData), resulting in
+only the first 1D array to be returned. See https://github.com/root-project/root/issues/17729
+
+Since this C++ pythonization was added with the upgrade in 6.32, and is only
+defined and used recursively, the safe option is to disable this function and
+no longer add it. It is temporarily removed to prevent errors due to -Wunused-function
+---
+ bindings/pyroot/cppyy/CPyCppyy/src/Pythonize.cxx | 16 +++++++++++++++-
+ 1 file changed, 15 insertions(+), 1 deletion(-)
+
+diff --git a/bindings/pyroot/cppyy/CPyCppyy/src/Pythonize.cxx b/bindings/pyroot/cppyy/CPyCppyy/src/Pythonize.cxx
+index 9b87905bab..0510c1c6ac 100644
+--- a/bindings/pyroot/cppyy/CPyCppyy/src/Pythonize.cxx
++++ b/bindings/pyroot/cppyy/CPyCppyy/src/Pythonize.cxx
+@@ -527,6 +527,13 @@ PyObject* VectorData(PyObject* self, PyObject*)
+ }
+
+
++// This function implements __array__, added to std::vector python proxies and causes
++// a bug (see explanation at Utility::AddToClass(pyclass, "__array__"...) in CPyCppyy::Pythonize)
++// The recursive nature of this function, passes each subarray (pydata) to the next call and only
++// the final buffer is cast to a lowlevel view and resized (in VectorData), resulting in only the
++// first 1D array to be returned. See https://github.com/root-project/root/issues/17729
++// It is temporarily removed to prevent errors due to -Wunused-function, since it is no longer added.
++#if 0
+ //---------------------------------------------------------------------------
+ PyObject* VectorArray(PyObject* self, PyObject* args, PyObject* kwargs)
+ {
+@@ -537,7 +544,7 @@ PyObject* VectorArray(PyObject* self, PyObject* args, PyObject* kwargs)
+     Py_DECREF(pydata);
+     return newarr;
+ }
+-
++#endif
+
+ //-----------------------------------------------------------------------------
+ static PyObject* vector_iter(PyObject* v) {
+@@ -1810,8 +1817,15 @@ bool CPyCppyy::Pythonize(PyObject* pyclass, const std::string& name)
+             Utility::AddToClass(pyclass, "__real_data", "data");
+             Utility::AddToClass(pyclass, "data", (PyCFunction)VectorData);
+
++        // The addition of the __array__ utility to std::vector Python proxies causes a
++        // bug where the resulting array is a single dimension, causing loss of data when
++        // converting to numpy arrays, for >1dim vectors. Since this C++ pythonization
++        // was added with the upgrade in 6.32, and is only defined and used recursively,
++        // the safe option is to disable this function and no longer add it.
++#if 0
+         // numpy array conversion
+             Utility::AddToClass(pyclass, "__array__", (PyCFunction)VectorArray);
++#endif
+
+         // checked getitem
+             if (HasAttrDirect(pyclass, PyStrings::gLen)) {
+-- 
+2.43.0
+
@@ -46,6 +46,7 @@ git apply patches/CPyCppyy-Adapt-to-no-std-in-ROOT.patch
 git apply patches/CPyCppyy-Always-convert-returned-std-string.patch
 git apply patches/CPyCppyy-Disable-implicit-conversion-to-smart-ptr.patch
 git apply patches/CPyCppyy-TString_converter.patch
+git apply patches/CPyCppyy-Disable_std-vector-numpy-array-pythonization.patch
 git apply patches/cppyy-No-CppyyLegacy-namespace.patch
 git apply patches/cppyy-Remove-Windows-workaround.patch
 git apply patches/cppyy-Don-t-enable-cling-autoloading.patch