make amendments

Author: isidentical

Lib/test/test_traceback.py

@@ -6,15 +6,18 @@
 import sys
 import inspect
 import unittest
+import tempfile
 import re
 from test import support
 from test.support import (Error, captured_output, cpython_only, ALWAYS_EQ,
                           requires_debug_ranges, has_no_debug_ranges)
 from test.support.os_helper import TESTFN, unlink
 from test.support.script_helper import assert_python_ok, assert_python_failure
-import textwrap
 
+import os
+import textwrap
 import traceback
+from functools import partial
 
 
 test_code = namedtuple('code', ['co_filename', 'co_name'])
@@ -460,7 +463,29 @@ def f_with_subscript():
         result_lines = self.get_exception(f_with_subscript)
         self.assertEqual(result_lines, expected_error.splitlines())
 
+    def test_traceback_specialization_with_syntax_error(self):
+        with tempfile.NamedTemporaryFile(mode="w", suffix=".py", delete=False) as file:
+            bytecode = compile("1 / 0 / 1 / 2\n", file.name, "exec")
+
+            # make the file invalid
+            file.write("1 $ 0 / 1 / 2\n")
+            file.flush()
 
+        func = partial(exec, bytecode)
+        result_lines = self.get_exception(func)
+        os.unlink(file.name)
+
+        lineno_f = bytecode.co_firstlineno
+        expected_error = (
+            'Traceback (most recent call last):\n'
+            f'  File "{__file__}", line {self.callable_line}, in get_exception\n'
+            '    callable()\n'
+            '    ^^^^^^^^^^\n'
+            f'  File "{file.name}", line {lineno_f}, in <module>\n'
+            "    1 $ 0 / 1 / 2\n"
+            '    ^^^^^\n'
+        )
+        self.assertEqual(result_lines, expected_error.splitlines())
 
 @cpython_only
 @requires_debug_ranges()

Lib/traceback.py

@@ -505,9 +505,9 @@ def format(self):
                     row.append(' ' * (colno - stripped_characters))
 
                     if anchors:
-                        row.append('~' * (anchors[0]))
-                        row.append('^' * (anchors[1] - anchors[0]))
-                        row.append('~' * (end_colno - colno - anchors[1]))
+                        row.append(anchors.primary_char * (anchors.left_end_offset))
+                        row.append(anchors.secondary_char * (anchors.right_start_offset - anchors.left_end_offset))
+                        row.append(anchors.primary_char * (end_colno - colno - anchors.right_start_offset))
                     else:
                         row.append('^' * (end_colno - colno))
 
@@ -534,6 +534,17 @@ def _byte_offset_to_character_offset(str, offset):
     return len(as_utf8[:offset + 1].decode("utf-8"))
 
 
+_Anchors = collections.namedtuple(
+    "_Anchors",
+    [
+        "left_end_offset",
+        "right_start_offset",
+        "primary_char",
+        "secondary_char",
+    ],
+    defaults=["~", "^"]
+)
+
 def _extract_caret_anchors_from_line_segment(segment):
     import ast
 
@@ -560,9 +571,9 @@ def _extract_caret_anchors_from_line_segment(segment):
                         and not operator_str[operator_offset + 1].isspace()
                     ):
                         right_anchor += 1
-                    return left_anchor, right_anchor
+                    return _Anchors(left_anchor, right_anchor)
                 case ast.Subscript():
-                    return expr.value.end_col_offset, expr.slice.end_col_offset + 1
+                    return _Anchors(expr.value.end_col_offset, expr.slice.end_col_offset + 1)
 
     return None
 

Python/traceback.c

@@ -539,7 +539,7 @@ static int
 extract_anchors_from_expr(const char *segment_str, expr_ty expr, Py_ssize_t *left_anchor, Py_ssize_t *right_anchor,
                           char** primary_error_char, char** secondary_error_char)
 {
-switch (expr->kind) {
+    switch (expr->kind) {
         case BinOp_kind: {
             expr_ty left = expr->v.BinOp.left;
             expr_ty right = expr->v.BinOp.right;
@@ -743,23 +743,20 @@ tb_displayline(PyTracebackObject* tb, PyObject *f, PyObject *filename, int linen
     // right_end_offset will be set to -1.
 
     // Convert the utf-8 byte offset to the actual character offset so we print the right number of carets.
-    Py_ssize_t start_offset = (Py_ssize_t)start_col_byte_offset;
-    Py_ssize_t end_offset = (Py_ssize_t)end_col_byte_offset;
+    assert(source_line);
+    Py_ssize_t start_offset = _PyPegen_byte_offset_to_character_offset(source_line, start_col_byte_offset);
+    Py_ssize_t end_offset = _PyPegen_byte_offset_to_character_offset(source_line, end_col_byte_offset);
     Py_ssize_t left_end_offset = -1;
     Py_ssize_t right_start_offset = -1;
 
     char *primary_error_char = "^";
     char *secondary_error_char = primary_error_char;
 
-    if (source_line) {
-        start_offset = _PyPegen_byte_offset_to_character_offset(source_line, start_col_byte_offset);
-        end_offset = _PyPegen_byte_offset_to_character_offset(source_line, end_col_byte_offset);
-        int res = extract_anchors_from_line(filename, source_line, start_offset, end_offset,
-                                            &left_end_offset, &right_start_offset,
-                                            &primary_error_char, &secondary_error_char);
-        if (res < 0 && ignore_source_errors() < 0) {
-            goto done;
-        }
+    int res = extract_anchors_from_line(filename, source_line, start_offset, end_offset,
+                                        &left_end_offset, &right_start_offset,
+                                        &primary_error_char, &secondary_error_char);
+    if (res < 0 && ignore_source_errors() < 0) {
+        goto done;
     }
 
     err = print_error_location_carets(f, truncation, start_offset, end_offset,