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Fix schemagen integer parser rejecting zero with negative exponents

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Move the zero-detection check in the generated parseJsonInt64 before the
finalExp < 0 guard. Previously, valid JSON numbers whose mathematical
value is 0 but written with a large negative exponent (e.g. 0e-2,
0.0e-2, -0e-2, 0e-20) were rejected because the negative-finalExp early
return ran before the all-zero-digits branch could set out = 0. Non-zero
values with negative exponents are still correctly rejected.

Closes #56
This commit is contained in:
weaselbot
2026-07-19 22:00:15 -04:00
parent 16f5d3cd9d
commit cdff634057
2 changed files with 11 additions and 1 deletions
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contrib/schemagen/test_schemagen.py
+10
View File
@@ -592,6 +592,13 @@ class SchemagenIntegerBoundaryTest(unittest.TestCase):
("123.0", "WeaselJson_OK", 123), ("123.0", "WeaselJson_OK", 123),
("9e18", "WeaselJson_OK", 9000000000000000000), ("9e18", "WeaselJson_OK", 9000000000000000000),
("10e18", "WeaselJson_REJECT", 0), ("10e18", "WeaselJson_REJECT", 0),
# Issue #56: zero written with a negative exponent must be accepted.
("0e-1", "WeaselJson_OK", 0),
("0e-2", "WeaselJson_OK", 0),
("0.0e-2", "WeaselJson_OK", 0),
("-0e-2", "WeaselJson_OK", 0),
("0e-20", "WeaselJson_OK", 0),
("0.000e-5", "WeaselJson_OK", 0),
] ]
cases_src = self._build_cases_array("root", cases) cases_src = self._build_cases_array("root", cases)
harness = textwrap.dedent( harness = textwrap.dedent(
@@ -634,6 +641,9 @@ class SchemagenIntegerBoundaryTest(unittest.TestCase):
('{"age":2.0}', "WeaselJson_OK", 2), ('{"age":2.0}', "WeaselJson_OK", 2),
('{"age":0.0001e4}', "WeaselJson_OK", 1), ('{"age":0.0001e4}', "WeaselJson_OK", 1),
('{"age":0.001}', "WeaselJson_REJECT", 0), ('{"age":0.001}', "WeaselJson_REJECT", 0),
# Issue #56: zero written with a negative exponent must be accepted.
('{"age":0e-2}', "WeaselJson_OK", 0),
('{"age":-0e-20}', "WeaselJson_OK", 0),
( (
'{"age":-9223372036854775808.0}', '{"age":-9223372036854775808.0}',
"WeaselJson_OK", "WeaselJson_OK",
contrib/schemagen/weaseljson_schemagen.py
+1 -1
View File
@@ -1058,10 +1058,10 @@ private:
++trim; ++trim;
}} }}
int64_t finalExp = exp - fracDigits + trim; int64_t finalExp = exp - fracDigits + trim;
if (finalExp < 0) return false;
size_t leadingZeros = 0; size_t leadingZeros = 0;
while (leadingZeros < digits.size() && digits[leadingZeros] == '0') ++leadingZeros; while (leadingZeros < digits.size() && digits[leadingZeros] == '0') ++leadingZeros;
if (leadingZeros == digits.size()) {{ out = 0; return true; }} if (leadingZeros == digits.size()) {{ out = 0; return true; }}
if (finalExp < 0) return false;
if (leadingZeros > 0) digits.erase(0, leadingZeros); if (leadingZeros > 0) digits.erase(0, leadingZeros);
constexpr uint64_t kMaxNeg = 9223372036854775808ULL; constexpr uint64_t kMaxNeg = 9223372036854775808ULL;