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[3.13] gh-152157: Reject empty fractions in _datetime.{date}time.fromisoformat (GH-152161) #152766

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Merged
StanFromIreland merged 3 commits into from
Jul 8, 2026
Merged

[3.13] gh-152157: Reject empty fractions in _datetime.{date}time.fromisoformat (GH-152161) #152766

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96c10f1
gh-152157: Reject empty fractions in `_datetime.{date}time.fromisofor…
tonghuaroot Jul 1, 2026
d464f07
Merge remote-tracking branch 'origin/3.13' into HEAD
tonghuaroot Jul 7, 2026
a5042a7
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StanFromIreland Jul 8, 2026
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8 changes: 8 additions & 0 deletions Lib/test/datetimetester.py
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Original file line number Diff line number Diff line change
Expand Up @@ -3396,6 +3396,10 @@ def test_fromisoformat_fails_datetime(self):
'2009-04-19T12:30:45.400 ', # Trailing space (gh-130959)
'2009-04-19T12:30:45. 400', # Space before fraction (gh-130959)
'2020-2020', # Ambiguous 9-char date portion
'2009-04-19T12:30:45.+05:00', # Empty fraction before offset
'2009-04-19T12:30:45.-05:00', # Empty fraction before offset
'2009-04-19T12:30:45.Z', # Empty fraction before Z
'2009-04-19T12:30:45,+05:00', # Empty fraction (comma) before offset
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]

for bad_str in bad_strs:
Expand Down Expand Up @@ -4509,6 +4513,10 @@ def test_fromisoformat_fails(self):
'12:30:45.400 +02:30', # Space between ms and timezone (gh-130959)
'12:30:45.400 ', # Trailing space (gh-130959)
'12:30:45. 400', # Space before fraction (gh-130959)
'12:30:45.+05:00', # Empty fraction before offset
'12:30:45.-05:00', # Empty fraction before offset
'12:30:45.Z', # Empty fraction before Z
'12:30:45,+05:00', # Empty fraction (comma) before offset
]

for bad_str in bad_strs:
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3 changes: 3 additions & 0 deletions Misc/NEWS.d/next/Library/2026-06-25-07-08-17.gh-issue-152157.dt5Ef0.rst
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Original file line number Diff line number Diff line change
@@ -0,0 +1,3 @@
The C implementations of :meth:`~datetime.datetime.fromisoformat` and :meth:`~datetime.time.fromisoformat`
now reject a decimal separator that is not followed by any
fractional digit before a timezone designator.
15 changes: 10 additions & 5 deletions Modules/_datetimemodule.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1013,17 +1013,22 @@ parse_hh_mm_ss_ff(const char *tstr, const char *tstr_end, int *hour,
has_separator = (c == ':');
}

if (p >= p_end) {
if (c == '.' || c == ',') {
if (p >= p_end) {
return -3; // Decimal mark not followed by any digit
}
break;
}
else if (p >= p_end) {
return c != '\0';
}
else if (has_separator && (c == ':')) {
continue;
}
else if (c == '.' || c == ',') {
break;
} else if (!has_separator) {
else if (!has_separator) {
--p;
} else {
}
else {
return -4; // Malformed time separator
}
}
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