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gh-149277: Fix error position for invalid numeric literals #149456

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gh-149277: Fix error position for invalid numeric literals #149456

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88d52b8
gh-149277: Fix error position for invalid numeric literals
anuj-bharambe2004 May 6, 2026
5bf3295
gh-149277: Fix error position for invalid numeric literals
anuj-bharambe2004 May 6, 2026
20996e1
Add tests for invalid numeric literal error offset
anuj-bharambe2004 May 6, 2026
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20 changes: 20 additions & 0 deletions Lib/test/test_grammar.py
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Original file line number Diff line number Diff line change
Expand Up @@ -140,6 +140,26 @@ def test_bad_numerical_literals(self):
check("1e2_", "invalid decimal literal")
check("1e+", "invalid decimal literal")

def test_end_of_numerical_literals_offset(self):
# gh-149277: verify the error caret points at the first invalid
# character, not the last valid digit.
cases = [

@pablogsal pablogsal Jul 11, 2026

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Nit: the cases here all go through verify_end_of_number. Can we add 0xI/0bz too so we lock the behaviour for the prefix-only path, and maybe assert .msg as well?

@pablogsal pablogsal Jul 30, 2026

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Nit: the cases here all go through verify_end_of_number. Can we add 0xI/0bz too so we lock the behaviour for the prefix-only path, and maybe assert .msg as well?

("0xfg", 4),
("0x9g", 4),
("0b1z", 4),
("0o7q", 4),
("9spam", 2),
("0xfspam", 4),
("1.0x", 4),
("1e3w", 4),
("1jz", 3),
]
for source, expected_offset in cases:
Comment on lines +143 to +157

@picnixz picnixz May 9, 2026

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Use @subTests decorator for cases instead of this loop and subTest().

with self.subTest(source=source):
with self.assertRaises(SyntaxError) as cm:
compile(source, "<test>", "eval")
self.assertEqual(cm.exception.offset, expected_offset)

@picnixz picnixz May 9, 2026

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Please also test the rendered carret not just the carret offset. Use check_syntax_error for that.


Comment on lines +143 to +162

@skirpichev skirpichev Jul 29, 2026

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Suggested change
def test_end_of_numerical_literals_offset(self):
# gh-149277: verify the error caret points at the first invalid
# character, not the last valid digit.
cases = [
("0xfg", 4),
("0x9g", 4),
("0b1z", 4),
("0o7q", 4),
("9spam", 2),
("0xfspam", 4),
("1.0x", 4),
("1e3w", 4),
("1jz", 3),
]
for source, expected_offset in cases:
with self.subTest(source=source):
with self.assertRaises(SyntaxError) as cm:
compile(source, "<test>", "eval")
self.assertEqual(cm.exception.offset, expected_offset)
@subTests('source,offset,msg',
[("0xfg", 4, "hexadecimal"),
("0x9g", 4, "hexadecimal"),
("0b1z", 4, "binary"),
("0o7q", 4, "octal"),
("9spam", 2, " decimal"),
("0xfspam", 4, "hexadecimal"),
("1.0x", 4, " decimal"),
("1e3w", 4, " decimal"),
("1jz", 3, "imaginary"),
("0xI", 3, "hexadecimal"),
("0bz", 3, "binary"),
])
def test_end_of_numerical_literals_offset(self, source, offset, msg):
# gh-149277: verify the error caret points at the first invalid
# character, not the last valid digit.
with self.assertRaises(SyntaxError) as cm:
compile(source, "<test>", "eval")
self.assertEqual(cm.exception.offset, offset)
self.assertIn(msg, cm.exception.msg)

def test_end_of_numerical_literals(self):
def check(test, error=False):
with self.subTest(expr=test):
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2 changes: 2 additions & 0 deletions Misc/NEWS.d/next/Core_and_Builtins/2026-05-06-18-16-33.gh-issue-149277.4uVfSK.rst
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Original file line number Diff line number Diff line change
@@ -0,0 +1,2 @@
Fix the :exc:`SyntaxError` caret position for invalid numeric literals to
point at the first invalid character instead of the last valid one.
1 change: 0 additions & 1 deletion Parser/lexer/lexer.c
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Expand Up @@ -352,7 +352,6 @@ verify_end_of_number(struct tok_state *tok, int c, const char *kind) {
}
else /* In future releases, only error will remain. */
if (c < 128 && is_potential_identifier_char(c)) {
tok_backup(tok, c);
_PyTokenizer_syntaxerror(tok, "invalid %s literal", kind);
return 0;
}
Expand Down
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