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