Use std::move in c++ during yield context switch. (GH-4154)

When compiling pyarrow with cython 3.0 we get an error about the copy constructor of an object has been deleted on the generated context switch code.

Also make the "cpp_temp_assignment" test only run in C++11 since it is based on `std::move()`.

Cython/Compiler/ExprNodes.py

@@ -9898,7 +9898,12 @@ class YieldExprNode(ExprNode):
         for cname, type, manage_ref in code.funcstate.temps_in_use():
             save_cname = code.funcstate.closure_temps.allocate_temp(type)
             saved.append((cname, save_cname, type))
-            code.put_xgiveref(cname, type)
+            if type.is_cpp_class:
+                code.globalstate.use_utility_code(
+                    UtilityCode.load_cached("MoveIfSupported", "CppSupport.cpp"))
+                cname = "__PYX_STD_MOVE_IF_SUPPORTED(%s)" % cname
+            else:
+                code.put_xgiveref(cname, type)
             code.putln('%s->%s = %s;' % (Naming.cur_scope_cname, save_cname, cname))
 
         code.put_xgiveref(Naming.retval_cname, py_object_type)
@@ -9929,9 +9934,12 @@ class YieldExprNode(ExprNode):
 
         code.put_label(label_name)
         for cname, save_cname, type in saved:
-            code.putln('%s = %s->%s;' % (cname, Naming.cur_scope_cname, save_cname))
+            save_cname = "%s->%s" % (Naming.cur_scope_cname, save_cname)
+            if type.is_cpp_class:
+                save_cname = "__PYX_STD_MOVE_IF_SUPPORTED(%s)" % save_cname
+            code.putln('%s = %s;' % (cname, save_cname))
             if type.is_pyobject:
-                code.putln('%s->%s = 0;' % (Naming.cur_scope_cname, save_cname))
+                code.putln('%s = 0;' % save_cname)
                 code.put_xgotref(cname, type)
         self.generate_sent_value_handling_code(code, Naming.sent_value_cname)
         if self.result_is_used:

runtests.py

@@ -2089,7 +2089,7 @@ def main():
             args.append(arg)
 
     from optparse import OptionParser
-    parser = OptionParser()
+    parser = OptionParser(usage="usage: %prog [options] [selector ...]")
     parser.add_option("--no-cleanup", dest="cleanup_workdir",
                       action="store_false", default=True,
                       help="do not delete the generated C files (allows passing --no-cython on next run)")

tests/compile/cpp_temp_assignment.pyx

-# tag: cpp
+# tag: cpp,cpp11
 # mode: compile
 
 cdef extern from *:
     """
-    #if __cplusplus >= 201103L
+    class NoAssignIterator {
+        public:
+            explicit NoAssignIterator(int pos) : pos_(pos) {}
+            NoAssignIterator(NoAssignIterator&) = delete;
+            NoAssignIterator(NoAssignIterator&&) {}
+            NoAssignIterator& operator=(NoAssignIterator&) = delete;
+            NoAssignIterator& operator=(NoAssignIterator&&) { return *this; }
+            // Default constructor of temp variable is needed by Cython
+            // as of 3.0a6.
+            NoAssignIterator() : pos_(0) {}
+            int operator*() {
+                return pos_;
+            }
+            NoAssignIterator operator++() {
+                return NoAssignIterator(pos_ + 1);
+            }
+            int operator!=(NoAssignIterator other) {
+                return pos_ != other.pos_;
+            }
+            int pos_;
+    };
     class NoAssign {
         public:
             NoAssign() {}
@@ -12,15 +32,13 @@ cdef extern from *:
             NoAssign& operator=(NoAssign&) = delete;
             NoAssign& operator=(NoAssign&&) { return *this; }
             void func() {}
+            NoAssignIterator begin() {
+                return NoAssignIterator(0);
+            }
+            NoAssignIterator end() {
+                return NoAssignIterator(2);
+            }
     };
-    #else
-    // the test becomes meaningless
-    // (but just declare something to ensure it passes)
-    class NoAssign {
-        public:
-            void func() {}
-    };
-    #endif
 
     NoAssign get_NoAssign_Py() {
         return NoAssign();
@@ -28,9 +46,17 @@ cdef extern from *:
     NoAssign get_NoAssign_Cpp() {
         return NoAssign();
     }
+
     """
+    cdef cppclass NoAssignIterator:
+        int operator*()
+        NoAssignIterator operator++()
+        int operator!=(NoAssignIterator)
+
     cdef cppclass NoAssign:
         void func()
+        NoAssignIterator begin()
+        NoAssignIterator end()
 
     # might raise Python exception (thus needs a temp)
     NoAssign get_NoAssign_Py() except *
@@ -63,3 +89,7 @@ cdef class AssignToClassAttr:
     def __init__(self):
         self.attr = get_NoAssign_Py()
         self.attr = get_NoAssign_Cpp()
+
+def test_generator_cpp_iterator_as_temp():
+    for i in get_NoAssign_Py():
+        yield i