Fix some issues when optimising the builtin memoryview (GH-5271)

Error in capitalization.
Closes https://github.com/cython/cython/issues/5270 

Context managers were being optimized into a non-working state when involving a CloneNode.
Closes https://github.com/cython/cython/issues/5268

5 files changed, 36 insertions, 6 deletions

diff --git a/Cython/Compiler/Builtin.py b/Cython/Compiler/Builtin.py
index 6e5a65b85..cfdb25123 100644
--- a/Cython/Compiler/Builtin.py
+++ b/Cython/Compiler/Builtin.py
@@ -364,21 +364,21 @@ builtin_types_table = [
         # TODO - format would be nice, but hard to get
         # __len__ can be accessed through a direct lookup of the buffer (but probably in Optimize.c)
         # error checking would ideally be limited api only
-        BuiltinProperty("ndim", PyrexTypes.c_int_type, '__Pyx_PyMemoryview_Get_ndim',
+        BuiltinProperty("ndim", PyrexTypes.c_int_type, '__Pyx_PyMemoryView_Get_ndim',
                         exception_value="-1", exception_check=True,
                         utility_code=TempitaUtilityCode.load_cached(
                             "memoryview_get_from_buffer", "Builtins.c",
                             context=dict(name="ndim")
                         )
         ),
-        BuiltinProperty("readonly", PyrexTypes.c_bint_type, '__Pyx_PyMemoryview_Get_readonly',
+        BuiltinProperty("readonly", PyrexTypes.c_bint_type, '__Pyx_PyMemoryView_Get_readonly',
                         exception_value="-1", exception_check=True,
                         utility_code=TempitaUtilityCode.load_cached(
                             "memoryview_get_from_buffer", "Builtins.c",
                             context=dict(name="readonly")
                         )
         ),
-        BuiltinProperty("itemsize", PyrexTypes.c_py_ssize_t_type, '__Pyx_PyMemoryview_Get_itemsize',
+        BuiltinProperty("itemsize", PyrexTypes.c_py_ssize_t_type, '__Pyx_PyMemoryView_Get_itemsize',
                         exception_value="-1", exception_check=True,
                         utility_code=TempitaUtilityCode.load_cached(
                             "memoryview_get_from_buffer", "Builtins.c",
diff --git a/Cython/Compiler/ParseTreeTransforms.py b/Cython/Compiler/ParseTreeTransforms.py
index 73af75cf7..4a3958a9c 100644
--- a/Cython/Compiler/ParseTreeTransforms.py
+++ b/Cython/Compiler/ParseTreeTransforms.py
@@ -1555,6 +1555,7 @@ class WithTransform(VisitorTransform, SkipDeclarations):
         pos = node.pos
         is_async = node.is_async
         body, target, manager = node.body, node.target, node.manager
+        manager = node.manager = ExprNodes.ProxyNode(manager)
         node.enter_call = ExprNodes.SimpleCallNode(
             pos, function=ExprNodes.AttributeNode(
                 pos, obj=ExprNodes.CloneNode(manager),
diff --git a/Cython/Compiler/PyrexTypes.py b/Cython/Compiler/PyrexTypes.py
index b431255e4..f3d279356 100644
--- a/Cython/Compiler/PyrexTypes.py
+++ b/Cython/Compiler/PyrexTypes.py
@@ -1459,6 +1459,9 @@ class BuiltinObjectType(PyObjectType):
         elif type_name == 'int':
             # For backwards compatibility of (Py3) 'x: int' annotations in Py2, we also allow 'long' there.
             type_check = '__Pyx_Py3Int_Check'
+        elif type_name == "memoryview":
+            # captialize doesn't catch the 'V'
+            type_check = "PyMemoryView_Check"
         else:
             type_check = 'Py%s_Check' % type_name.capitalize()
         if exact and type_name not in ('bool', 'slice', 'Exception'):
diff --git a/Cython/Utility/Builtins.c b/Cython/Utility/Builtins.c
index b9de4104c..cf0c69e62 100644
--- a/Cython/Utility/Builtins.c
+++ b/Cython/Utility/Builtins.c
@@ -546,7 +546,7 @@ static CYTHON_INLINE int __Pyx_PySet_Update(PyObject* set, PyObject* it) {
 
 // buffer is in limited api from Py3.11
 #if !CYTHON_COMPILING_IN_LIMITED_API || CYTHON_LIMITED_API >= 0x030b0000
-#define __Pyx_PyMemoryview_Get_{{name}}(o) PyMemoryView_GET_BUFFER(o)->{{name}}
+#define __Pyx_PyMemoryView_Get_{{name}}(o) PyMemoryView_GET_BUFFER(o)->{{name}}
 #else
 {{py:
 out_types = dict(
@@ -554,7 +554,7 @@ out_types = dict(
     len='Py_ssize_t', itemsize='Py_ssize_t')
 }} // can't get format like this unfortunately. It's unicode via getattr
 {{py: out_type = out_types[name]}}
-static {{out_type}} __Pyx_PyMemoryview_Get_{{name}}(PyObject *obj); /* proto */
+static {{out_type}} __Pyx_PyMemoryView_Get_{{name}}(PyObject *obj); /* proto */
 #endif
 
 ////////////// memoryview_get_from_buffer /////////////////////////
@@ -567,7 +567,7 @@ out_types = dict(
     len='Py_ssize_t', itemsize='Py_ssize_t')
 }}
 {{py: out_type = out_types[name]}}
-static {{out_type}} __Pyx_PyMemoryview_Get_{{name}}(PyObject *obj) {
+static {{out_type}} __Pyx_PyMemoryView_Get_{{name}}(PyObject *obj) {
     {{out_type}} result;
     PyObject *attr = PyObject_GetAttr(obj, PYIDENT("{{name}}"));
     if (!attr) {
diff --git a/tests/run/builtin_memory_view.pyx b/tests/run/builtin_memory_view.pyx
index 709be3b7d..34dd32ba7 100644
--- a/tests/run/builtin_memory_view.pyx
+++ b/tests/run/builtin_memory_view.pyx
@@ -4,6 +4,8 @@
 
 from __future__ import print_function
 
+import sys
+
 cimport cython
 #from cpython.memoryview cimport PyMemoryView_GET_BUFFER
 
@@ -38,3 +40,27 @@ def test_optimized_attributes(memoryview view):
     1 1 True
     """
     print(view.itemsize, view.ndim, view.readonly)
+
+def test_isinstance(x):
+    """
+    >>> test_isinstance(b"abc")
+    False
+    >>> test_isinstance(memoryview(b"abc"))
+    True
+    """
+    return isinstance(x, memoryview)
+
+def test_in_with(x):
+    """
+    This is really just a compile test. An optimization was being
+    applied in a way that generated invalid code
+    >>> test_in_with(b"abc")
+    98
+    """
+    if sys.version_info[0] < 3:
+        # Python 2 doesn't support memoryviews as context-managers
+        # so just skip the test
+        print(98)
+        return
+    with memoryview(x) as xv:
+        print(xv[1])