A Rust attribute macro to require that the compiler prove a function can't ever panic.
toml
[dependencies]
no-panic = "0.1"
```rust
extern crate nopanic; use nopanic::no_panic;
fn demo(s: &str) -> &str { &s[1..] }
fn main() { println!("{}", demo("input string")); } ```
If the function does panic (or the compiler fails to prove that the function cannot panic), the program fails to compile with a linker error that identifies the function name. Let's trigger that by passing a string that cannot be sliced at the first byte:
rust
fn main() {
println!("{}", demo("\u{1f980}input string"));
}
console
Compiling no-panic-demo v0.0.1
error: linking with `cc` failed: exit code: 1
|
= note: /no-panic-demo/target/release/deps/no_panic_demo-7170785b672ae322.no_p
anic_demo1-cba7f4b666ccdbcbbf02b7348e5df1b2.rs.rcgu.o: In function `_$LT$no_pani
c_demo..demo..__NoPanic$u20$as$u20$core..ops..drop..Drop$GT$::drop::h72f8f423002
b8d9f':
no_panic_demo1-cba7f4b666ccdbcbbf02b7348e5df1b2.rs:(.text._ZN72_$LT$no
_panic_demo..demo..__NoPanic$u20$as$u20$core..ops..drop..Drop$GT$4drop17h72f8f42
3002b8d9fE+0x2): undefined reference to `RUST_PANIC_IN_FUNCTION<demo>'
collect2: error: ld returned 1 exit status
The error is not stellar but notice the useful part at the end that provides the
name of the offending function: undefined reference to
`RUST_PANIC_IN_FUNCTION<demo>'
Requires rustc >=1.30.0.
Functions that require some amount of optimization to prove that they do not
panic may no longer compile in debug mode after being marked #[no_panic].
The attribute is useless in code built with panic = "abort".
The linker error technique is based on [@Kixunil]'s crate [dont_panic].
Check out that crate for other convenient ways to require absence of panics.
Licensed under either of
at your option.
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in this crate by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.