From: Pablo Galindo Salgado <Pablogsal@gmail.com>
Date: Mon, 27 Nov 2023 18:37:48 +0000 (+0000)
Subject: gh-112387: Fix error positions for decoded strings with backwards tokenize errors... 
X-Git-Tag: v3.13.0a3~616
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=45d648597b1146431bf3d91041e60d7f040e70bf;p=thirdparty%2FPython%2Fcpython.git

gh-112387: Fix error positions for decoded strings with backwards tokenize errors (#112409)

Signed-off-by: Pablo Galindo <pablogsal@gmail.com>
---

diff --git a/Lib/test/test_syntax.py b/Lib/test/test_syntax.py
index e80e95383b89..99433df73387 100644
--- a/Lib/test/test_syntax.py
+++ b/Lib/test/test_syntax.py
@@ -2334,6 +2334,10 @@ func(
 """
         self._check_error(code, "parenthesis '\\)' does not match opening parenthesis '\\['")
 
+        # Examples with dencodings
+        s = b'# coding=latin\n(aaaaaaaaaaaaaaaaa\naaaaaaaaaaa\xb5'
+        self._check_error(s, "'\(' was never closed")
+
     def test_error_string_literal(self):
 
         self._check_error("'blech", r"unterminated string literal \(.*\)$")
diff --git a/Misc/NEWS.d/next/Core and Builtins/2023-11-25-22-39-44.gh-issue-112387.AbBq5W.rst b/Misc/NEWS.d/next/Core and Builtins/2023-11-25-22-39-44.gh-issue-112387.AbBq5W.rst
new file mode 100644
index 000000000000..adac11bf4c90
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2023-11-25-22-39-44.gh-issue-112387.AbBq5W.rst	
@@ -0,0 +1,2 @@
+Fix error positions for decoded strings with backwards tokenize errors.
+Patch by Pablo Galindo
diff --git a/Parser/pegen_errors.c b/Parser/pegen_errors.c
index 2528d4502b3c..20232f3a26a2 100644
--- a/Parser/pegen_errors.c
+++ b/Parser/pegen_errors.c
@@ -282,6 +282,10 @@ get_error_line_from_tokenizer_buffers(Parser *p, Py_ssize_t lineno)
     Py_ssize_t relative_lineno = p->starting_lineno ? lineno - p->starting_lineno + 1 : lineno;
     const char* buf_end = p->tok->fp_interactive ? p->tok->interactive_src_end : p->tok->inp;
 
+    if (buf_end < cur_line) {
+        buf_end = cur_line + strlen(cur_line);
+    }
+
     for (int i = 0; i < relative_lineno - 1; i++) {
         char *new_line = strchr(cur_line, '\n');
         // The assert is here for debug builds but the conditional that