ES lexer crashes on numbers in e notation with large exponent

[asterite3]

Describe the bug

ECMAScript lexer crashes on numbers in scientific (e) notation with large exponents: namely, exponents that become infinite when parsed as Rust's f64. An example of such number is 1e10000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000. Another example is 1e-10000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 (with negative exponent)

The reason for this bug is that, when such exponent is parsed as Rust's f64 and is converted to string, it becomes the string inf. It is then appended to a string forming the whole resulting number, which becomes something like 1e+inf, which is invalid. It happens here

swc/crates/swc_ecma_parser/src/lexer/number.rs

Line 143 in 1ea965c

write!(raw_val, "{}", exp).unwrap();

Because strings like 1e+inf are invalid, code raw_val.parse().expect("failed to parse float literal"), that comes next, panics.

Crash can be reproduced with this program https://gist.github.com/asterite3/ca2208452b398fa7914c53581f01488d (or, by running SWC as NodeJS module).

Backtrace is:

thread 'main' panicked at 'failed to parse float literal: ParseFloatError { kind: Invalid }', .../swc/crates/swc_ecma_parser/src/lexer/number.rs:146:35
stack backtrace:
   0: rust_begin_unwind
             at /rustc/ad442399756573dccacb314b6bf8079964bcc72a/library/std/src/panicking.rs:498:5
   1: core::panicking::panic_fmt
             at /rustc/ad442399756573dccacb314b6bf8079964bcc72a/library/core/src/panicking.rs:106:14
   2: core::result::unwrap_failed
             at /rustc/ad442399756573dccacb314b6bf8079964bcc72a/library/core/src/result.rs:1613:5
   3: core::result::Result<T,E>::expect
             at /rustc/ad442399756573dccacb314b6bf8079964bcc72a/library/core/src/result.rs:1255:23
   4: swc_ecma_parser::lexer::number::<impl swc_ecma_parser::lexer::Lexer<I>>::read_number
             at ./crates/swc_ecma_parser/src/lexer/number.rs:146:19
   5: swc_ecma_parser::lexer::Lexer<I>::read_token
             at ./crates/swc_ecma_parser/src/lexer/mod.rs:281:24
   6: swc_ecma_parser::lexer::state::<impl core::iter::traits::iterator::Iterator for swc_ecma_parser::lexer::Lexer<I>>::next::{{closure}}
             at ./crates/swc_ecma_parser/src/lexer/state.rs:292:13
   7: swc_ecma_parser::lexer::state::<impl core::iter::traits::iterator::Iterator for swc_ecma_parser::lexer::Lexer<I>>::next
             at ./crates/swc_ecma_parser/src/lexer/state.rs:172:19
   8: swc_ecma_parser::parser::input::Buffer<I>::bump_inner::{{closure}}
             at ./crates/swc_ecma_parser/src/parser/input.rs:297:48
   9: core::option::Option<T>::or_else
             at /rustc/ad442399756573dccacb314b6bf8079964bcc72a/library/core/src/option.rs:1147:21
  10: swc_ecma_parser::parser::input::Buffer<I>::bump_inner
             at ./crates/swc_ecma_parser/src/parser/input.rs:297:20
  11: swc_ecma_parser::parser::input::Buffer<I>::cur
             at ./crates/swc_ecma_parser/src/parser/input.rs:378:13
  12: swc_ecma_parser::parser::input::Buffer<I>::cur_pos
             at ./crates/swc_ecma_parser/src/parser/input.rs:426:17
  13: swc_ecma_parser::parser::Parser<I>::parse_program
             at ./crates/swc_ecma_parser/src/parser/mod.rs:127:21
  14: tst::main
             at ./crates/swc/examples/tst.rs:20:11
  15: core::ops::function::FnOnce::call_once
             at /rustc/ad442399756573dccacb314b6bf8079964bcc72a/library/core/src/ops/function.rs:227:5

Input code

1e10000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000

Config

No response

Playground link

https://play.swc.rs/?version=1.2.115&code=H4sIAAAAAAAAAzNMNTQYBWQAAMkHImI5AQAA&config=H4sIAAAAAAAAA0WMTQrEIAxG75K1286id5hDBCctFv9IUhgR714tlu7C915ehUMsrBUyshCPS0pU%2FMMKZAOKZZcVTNf6tKEXagYUeScdiiyd%2BZSEJjUQXHRbGSWbQmYSeRHG3T9m66GQfucYKmjJdAc%2F0N7G%2FHPynaLySe0Cj9ke9LUAAAA%3D

Expected behavior

Expected behavior is to parse such numbers as

• either Infinity - when mantissa is nonzero and exponent is positive;
• or as 0 otherwise (when mantissa is zero or exponent is negative).

A somewhat edge case is when mantissa is itself so large that it parses as Infinity and exponent is negative. Both browsers and Babel parse this as 0.

This is what browsers do (I checked Chrome and Firefox), and Babel parses them like this too.

Version

1.2.120

Additional context

No response

[swc-bot]

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