// ignore-windows: Unwind panicking does not currently work on Windows #![allow(const_err)] use std::panic::{catch_unwind, AssertUnwindSafe}; use std::cell::Cell; thread_local! { static MY_COUNTER: Cell = Cell::new(0); static DROPPED: Cell = Cell::new(false); static HOOK_CALLED: Cell = Cell::new(false); } struct DropTester; impl Drop for DropTester { fn drop(&mut self) { DROPPED.with(|c| { c.set(true); }); } } fn do_panic_counter(do_panic: impl FnOnce(usize) -> !) { // If this gets leaked, it will be easy to spot // in Miri's leak report let _string = "LEAKED FROM do_panic_counter".to_string(); // When we panic, this should get dropped during unwinding let _drop_tester = DropTester; // Check for bugs in Miri's panic implementation. // If do_panic_counter() somehow gets called more than once, // we'll generate a different panic message and stderr will differ. let old_val = MY_COUNTER.with(|c| { let val = c.get(); c.set(val + 1); val }); do_panic(old_val); } fn main() { let prev = std::panic::take_hook(); std::panic::set_hook(Box::new(move |panic_info| { HOOK_CALLED.with(|h| h.set(true)); prev(panic_info) })); // Std panics test(|_old_val| std::panic!("Hello from panic: std")); test(|old_val| std::panic!(format!("Hello from panic: {:?}", old_val))); test(|old_val| std::panic!("Hello from panic: {:?}", old_val)); test(|_old_val| std::panic!(1337)); // Core panics test(|_old_val| core::panic!("Hello from panic: core")); test(|old_val| core::panic!(&format!("Hello from panic: {:?}", old_val))); test(|old_val| core::panic!("Hello from panic: {:?}", old_val)); // Built-in panics test(|_old_val| { let _val = [0, 1, 2][4]; loop {} }); test(|_old_val| { let _val = 1/0; loop {} }); // Cleanup: reset to default hook. drop(std::panic::take_hook()); eprintln!("Success!"); // Make sure we get this in stderr } fn test(do_panic: impl FnOnce(usize) -> !) { // Reset test flags. DROPPED.with(|c| c.set(false)); HOOK_CALLED.with(|c| c.set(false)); // Cause and catch a panic. let res = catch_unwind(AssertUnwindSafe(|| { let _string = "LEAKED FROM CLOSURE".to_string(); do_panic_counter(do_panic) })).expect_err("do_panic() did not panic!"); // See if we can extract the panic message. if let Some(s) = res.downcast_ref::() { eprintln!("Caught panic message (String): {}", s); } else if let Some(s) = res.downcast_ref::<&str>() { eprintln!("Caught panic message (&str): {}", s); } else { eprintln!("Failed get caught panic message."); } // Test flags. assert!(DROPPED.with(|c| c.get())); assert!(HOOK_CALLED.with(|c| c.get())); }