commit 71bb921829c33c30b2e111e18948df8c2b6731e4
author Lysandros Nikolaou <lisandrosnik@gmail.com> Sun Jun 21 05:47:22 2020 +0300
committer GitHub <noreply@github.com> Sat Jun 20 19:47:22 2020 -0700
tree cdcfa2d0ffed021c046d3dbc355fdeefa583b025
parent d301d9473e9a9b78d6e6678e9fe5ef66d46084e1

[3.9] bpo-41060: Avoid SEGFAULT when calling GET_INVALID_TARGET in the grammar (GH-21020) (GH-21024)



`GET_INVALID_TARGET` might unexpectedly return `NULL`, which if not
caught will cause a SEGFAULT. Therefore, this commit introduces a new
inline function `RAISE_SYNTAX_ERROR_INVALID_TARGET` that always
checks for `GET_INVALID_TARGET` returning NULL and can be used in
the grammar, replacing the long C ternary operation used till now.

(cherry picked from commit 6c4e0bd974f2895d42b63d9d004587e74b286c88)

Automerge-Triggered-By: @pablogsal

Grammar/python.gram

diff --git a/Grammar/python.gram b/Grammar/python.gram
index 314f1f5..8e6174f 100644
--- a/Grammar/python.gram
+++ b/Grammar/python.gram
@@ -655,9 +655,7 @@
     | a=expression ':' expression ['=' annotated_rhs] {
         RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "illegal target for annotation") }
     | (star_targets '=')* a=star_expressions '=' {
-        RAISE_SYNTAX_ERROR_KNOWN_LOCATION(
-            GET_INVALID_TARGET(a),
-            "cannot assign to %s", _PyPegen_get_expr_name(GET_INVALID_TARGET(a))) }
+        RAISE_SYNTAX_ERROR_INVALID_TARGET(STAR_TARGETS, a) }
     | (star_targets '=')* a=yield_expr '=' { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "assignment to yield expression not possible") }
     | a=star_expressions augassign (yield_expr | star_expressions) {
         RAISE_SYNTAX_ERROR_KNOWN_LOCATION( 
@@ -667,12 +665,7 @@
         )}
 invalid_del_stmt:
     | 'del' a=star_expressions {
-        GET_INVALID_DEL_TARGET(a) != NULL ?
-        RAISE_SYNTAX_ERROR_KNOWN_LOCATION(
-            GET_INVALID_DEL_TARGET(a),
-            "cannot delete %s", _PyPegen_get_expr_name(GET_INVALID_DEL_TARGET(a))
-        ) :
-        RAISE_SYNTAX_ERROR("invalid syntax") }
+        RAISE_SYNTAX_ERROR_INVALID_TARGET(DEL_TARGETS, a) }
 invalid_block:
     | NEWLINE !INDENT { RAISE_INDENTATION_ERROR("expected an indented block") }
 invalid_comprehension:
@@ -697,19 +690,11 @@
         RAISE_SYNTAX_ERROR("Cannot have two type comments on def") }
 invalid_with_item:
     | expression 'as' a=expression {
-        RAISE_SYNTAX_ERROR_KNOWN_LOCATION(
-            GET_INVALID_TARGET(a),
-            "cannot assign to %s", _PyPegen_get_expr_name(GET_INVALID_TARGET(a))
-        ) }
+        RAISE_SYNTAX_ERROR_INVALID_TARGET(STAR_TARGETS, a) }
 
 invalid_for_target:
     | ASYNC? 'for' a=star_expressions {
-        GET_INVALID_FOR_TARGET(a) != NULL ?
-        RAISE_SYNTAX_ERROR_KNOWN_LOCATION(
-            GET_INVALID_FOR_TARGET(a),
-            "cannot assign to %s", _PyPegen_get_expr_name(GET_INVALID_FOR_TARGET(a))
-        ) :
-        RAISE_SYNTAX_ERROR("invalid syntax") }
+        RAISE_SYNTAX_ERROR_INVALID_TARGET(FOR_TARGETS, a) }
 
 invalid_group:
     | '(' a=starred_expression ')' {