[GR-47464] Only evaluate LHS of annotated assignment once

PullRequest: graalpython/2882

Author: DSouzaM

graalpython/com.oracle.graal.python.test/src/tests/annotations/annotatedAssignments.py

@@ -0,0 +1,72 @@
+# Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
+# DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+#
+# The Universal Permissive License (UPL), Version 1.0
+#
+# Subject to the condition set forth below, permission is hereby granted to any
+# person obtaining a copy of this software, associated documentation and/or
+# data (collectively the "Software"), free of charge and under any and all
+# copyright rights in the Software, and any and all patent rights owned or
+# freely licensable by each licensor hereunder covering either (i) the
+# unmodified Software as contributed to or provided by such licensor, or (ii)
+# the Larger Works (as defined below), to deal in both
+#
+# (a) the Software, and
+#
+# (b) any piece of software and/or hardware listed in the lrgrwrks.txt file if
+# one is included with the Software each a "Larger Work" to which the Software
+# is contributed by such licensors),
+#
+# without restriction, including without limitation the rights to copy, create
+# derivative works of, display, perform, and distribute the Software and make,
+# use, sell, offer for sale, import, export, have made, and have sold the
+# Software and the Larger Work(s), and to sublicense the foregoing rights on
+# either these or other terms.
+#
+# This license is subject to the following condition:
+#
+# The above copyright notice and either this complete permission notice or at a
+# minimum a reference to the UPL must be included in all copies or substantial
+# portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+
+class Counter:
+  def __init__(self):
+    self.count = 0
+  def get(self, value):
+    self.count += 1
+    return value
+
+# Whether there's an RHS or not, each component of a slice and attribute assignment should be evaluated exactly once.
+
+arr = [0,0,0,0,0]
+
+c = Counter()
+c.get(arr)[c.get(0): c.get(2): c.get(1)]: (int, int)
+slice_no_assign_count = c.count
+
+c = Counter()
+c.get(arr)[c.get(0): c.get(2): c.get(1)]: (int, int) = (42, 42)
+slice_assign_count = c.count
+
+
+class Foo:
+  def __init__(self):
+    self.x = 42
+
+foo = Foo()
+
+c = Counter()
+c.get(foo).x: int
+attr_no_assign_count = c.count
+
+c = Counter()
+c.get(foo).x: int = 43
+attr_assign_count = c.count

graalpython/com.oracle.graal.python.test/src/tests/test_annotations.py

@@ -1,4 +1,4 @@
-# Copyright (c) 2019, 2022, Oracle and/or its affiliates. All rights reserved.
+# Copyright (c) 2019, 2023, Oracle and/or its affiliates. All rights reserved.
 # DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 #
 # The Universal Permissive License (UPL), Version 1.0
@@ -98,3 +98,11 @@ def test_addAnnotation():
     m.addAnnotation('myKey', 10)
     assert len(m.addAnnotation.__annotations__) == 2
     assert 10 == m.addAnnotation.__annotations__['myKey']
+
+def test_annotatedAssignments():
+    import annotations.annotatedAssignments as m
+
+    assert m.slice_no_assign_count == 4
+    assert m.slice_assign_count == 4
+    assert m.attr_no_assign_count == 1
+    assert m.attr_assign_count == 1

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/compiler/Compiler.java

@@ -2084,17 +2084,21 @@ public Void visit(StmtTy.AnnAssign node) {
                 addOp(STORE_SUBSCR);
             }
         } else if (node.target instanceof ExprTy.Attribute) {
-            ExprTy.Attribute attr = (ExprTy.Attribute) node.target;
-            checkForbiddenName(attr.attr, ExprContextTy.Store);
-            if (attr.value != null) {
-                checkAnnExpr(attr.value);
+            if (node.value == null) {
+                ExprTy.Attribute attr = (ExprTy.Attribute) node.target;
+                checkForbiddenName(attr.attr, ExprContextTy.Store);
+                if (attr.value != null) {
+                    checkAnnExpr(attr.value);
+                }
             }
         } else if (node.target instanceof ExprTy.Subscript) {
-            ExprTy.Subscript subscript = (ExprTy.Subscript) node.target;
-            if (subscript.value != null) {
-                checkAnnExpr(subscript.value);
+            if (node.value == null) {
+                ExprTy.Subscript subscript = (ExprTy.Subscript) node.target;
+                if (subscript.value != null) {
+                    checkAnnExpr(subscript.value);
+                }
+                checkAnnSubscr(subscript.slice);
             }
-            checkAnnSubscr(subscript.slice);
         } else {
             errorCallback.onError(ErrorType.Syntax, node.getSourceRange(), "invalid node type for annotated assignment");
         }