[GR-68568] Fix autopatch_capi overruning into preprocessor directives

PullRequest: graalpython/3946

Author: msimacek

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

@@ -1,4 +1,4 @@
-# Copyright (c) 2024, Oracle and/or its affiliates. All rights reserved.
+# Copyright (c) 2024, 2025, 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
@@ -54,7 +54,7 @@ def check_autopatched(source, expected):
             autopatch_capi.auto_patch(f.name, False)
             f.seek(0)
             actual = f.read()
-            assert actual == expected, f"Autopatch didn't make expected changes. Expected:\n{expected}\nActual:{actual}"
+            assert actual == expected, f"Autopatch didn't make expected changes. Expected:\n{expected}\nActual:\n{actual}"
 
 
     def test_replace_field_access():
@@ -106,3 +106,29 @@ def test_replace_field_access():
             #endif
             ''',
         )
+        check_autopatched(
+            '''
+             #if SOME_MACRO
+                         ((PyCFunctionObject *) func)->m_ml,
+             #else
+                         ((PyCFunctionObject *) func)->m_ml,
+             #endif
+             ''',
+            '''
+             #if SOME_MACRO
+                         GraalPyCFunction_GetMethodDef((PyObject*)(((PyCFunctionObject *) func))),
+             #else
+                         GraalPyCFunction_GetMethodDef((PyObject*)(((PyCFunctionObject *) func))),
+             #endif
+             ''',
+        )
+        check_autopatched(
+            '''
+            // PyList_SET_ITEM().
+            L->ob_item[len] = x;
+            ''',
+            '''
+            // PyList_SET_ITEM().
+            PySequence_Fast_ITEMS((PyObject*)L)[len] = x;
+            ''',
+        )

graalpython/lib-graalpython/modules/autopatch_capi.py

@@ -65,8 +65,13 @@ def replace_field_access(contents, match, replacement, assignment):
     start, end = match.span(1)
     level = 0
 
-    def consume_whitespace_backwards(idx):
-        while idx >= 0 and contents[idx].isspace():
+    def consume_whitespace_backwards(idx, newlines=True):
+        while idx >= 0 and contents[idx].isspace() and (not newlines or contents[idx] != '\n'):
+            idx -= 1
+        return idx
+
+    def consume_line_backwards(idx):
+        while idx >= 0 and contents[idx] != '\n':
             idx -= 1
         return idx
 
@@ -124,6 +129,13 @@ def consume_identifier_backwards(idx):
         else:
             idx += 1
             break
+        idx = consume_whitespace_backwards(idx, newlines=False)
+        if contents[idx + 1] == '\n':
+            # Get previous line. If it's a comment or a preprocessor directive, stop
+            line_start = consume_whitespace_forward(consume_line_backwards(idx))
+            if contents[line_start: line_start + 2].startswith(('#', '//')):
+                idx += 1
+                break
         idx = consume_whitespace_backwards(idx)
 
     receiver_start = consume_whitespace_forward(idx)