Re: [Tarantool-patches] [PATCH luajit] Fix binary number literal parsing.

[Maxim Kokryashkin via Tarantool-patches <tarantool-patches@dev.tarantool.org>]

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Hi, Sergey!
Thanks for the patch!
LGTM, except for a few comments below.
> 
>>From: Mike Pall <mike>
>>
>>Reported by Egor Skriptunoff.
>>
>>(cherry-picked from commit 377a8488b62a9f1b589bb68875dd1288aa70e76e)
>>
>>Binary number with fractional part is invalid. Parsing of such binary
>Typo: s/Binary/ A binary/
>Typo: s/fractional/a fractional/
>>numbers returns `STRSCAN_ERROR` for any numbers with non-zero fractional
>Typo: s/with/with a/
>>part, because it gives non-zero power of the exponent (`ex2`) in
>Typo: s/part,/part/
>Typo: s/non-zero/a non-zero/
>>`strscan_bin()`. But binary numbers with a zero fractional part
>>considered as valid numbers. To avoid such inconsistency the check, that
>Typo: s/considered as/are considered/
>>the given base doesn't equal 2, is added, when parsing decimal point
>Typo: s/parsing/parsing the/
>>part of the literal.
>>
>>Sergey Kaplun:
>>* added the description and the test for the problem
>>
>>Part of tarantool/tarantool#8825
>>---
>>
>>Branch:  https://github.com/tarantool/luajit/tree/skaplun/fix-binary-number-parsing
>>Issue:  https://github.com/tarantool/tarantool/issues/8825
>>ML:  https://www.freelists.org/post/luajit/Fractional-binary-number-literals
>>Tarantool PR:  https://github.com/tarantool/tarantool/pull/9028
>>
>>Tarantool's CI is red, because static build on aarch64 can't fetch the
>>LuaJIT's submodule commit somehow. Looks unrelated to the commit:).
>>
>> src/lj_strscan.c | 1 +
>> .../fix-binary-number-parsing.test.lua | 17 +++++++++++++++++
>> 2 files changed, 18 insertions(+)
>> create mode 100644 test/tarantool-tests/fix-binary-number-parsing.test.lua
>>
>>diff --git a/src/lj_strscan.c b/src/lj_strscan.c
>>index 11d341ee..a2d92714 100644
>>--- a/src/lj_strscan.c
>>+++ b/src/lj_strscan.c
>>@@ -444,6 +444,7 @@ StrScanFmt lj_strscan_scan(const uint8_t *p, MSize len, TValue *o,
>> 
>>     /* Handle decimal point. */
>>     if (dp) {
>>+ if (base == 2) return STRSCAN_ERROR;
>>       fmt = STRSCAN_NUM;
>>       if (dig) {
>>  ex = (int32_t)(dp-(p-1)); dp = p-1;
>>diff --git a/test/tarantool-tests/fix-binary-number-parsing.test.lua b/test/tarantool-tests/fix-binary-number-parsing.test.lua
>>new file mode 100644
>>index 00000000..df82bd0b
>>--- /dev/null
>>+++ b/test/tarantool-tests/fix-binary-number-parsing.test.lua
>>@@ -0,0 +1,17 @@
>>+local tap = require('tap')
>>+
>>+-- Test file to demonstrate incorrect behaviour of binary number
>>+-- parsing with fractional dot.
>>+-- See also:
>>+--  https://www.freelists.org/post/luajit/Fractional-binary-number-literals
>>+local test = tap.test('fix-binary-number-parsing')
>>+test:plan(2)
>>+
>>+-- Test that incorrect literal with non-0 fractional part still
>Typo: s/that/that an/
>Typo: s/with/with a/
>>+-- can't be converted to number.
>Typo: s/number/a number/
>>+test:is(tonumber('0b.1'), nil, '0b.1 is not converted')
>>+-- Test that incorrect literal with 0 fractional part can't be
>Typo: s/that/that an/
>>+-- converted to number.
>Typo: s/number/a number/
>>+test:is(tonumber('0b.0'), nil, '0b.0 is not converted')
>>+
>>+test:done(true)
>>--
>>2.41.0
>--
>Best regards,
>Maxim Kokryashkin
> 

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