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Implementing PanicHandlers for all places when new thread is spawned. Handling Client panics

This commit is contained in:
Tomusdrw 2016-02-10 12:50:27 +01:00
parent 0757ac1493
commit 2a498fc3eb
8 changed files with 299 additions and 105 deletions
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26
ethcore/src/block_queue.rs
View File

@ -26,6 +26,7 @@ use views::*;
use header::*;
use service::*;
use client::BlockStatus;
use util::panics::*;
/// Block queue status
#[derive(Debug)]
@ -59,6 +60,7 @@ impl BlockQueueInfo {
/// A queue of blocks. Sits between network or other I/O and the BlockChain.
/// Sorts them ready for blockchain insertion.
pub struct BlockQueue {
panic_handler: SafeStringPanicHandler,
engine: Arc<Box<Engine>>,
more_to_verify: Arc<Condvar>,
verification: Arc<Mutex<Verification>>,
@ -113,6 +115,7 @@ impl BlockQueue {
let ready_signal = Arc::new(QueueSignal { signalled: AtomicBool::new(false), message_channel: message_channel });
let deleting = Arc::new(AtomicBool::new(false));
let empty = Arc::new(Condvar::new());
let panic_handler = StringPanicHandler::new_thread_safe();
let mut verifiers: Vec<JoinHandle<()>> = Vec::new();
let thread_count = max(::num_cpus::get(), 3) - 2;
@ -123,11 +126,22 @@ impl BlockQueue {
let ready_signal = ready_signal.clone();
let empty = empty.clone();
let deleting = deleting.clone();
verifiers.push(thread::Builder::new().name(format!("Verifier #{}", i)).spawn(move || BlockQueue::verify(verification, engine, more_to_verify, ready_signal, deleting, empty))
.expect("Error starting block verification thread"));
let panic_handler = panic_handler.clone();
verifiers.push(
thread::Builder::new()
.name(format!("Verifier #{}", i))
.spawn(move || {
let mut panic = panic_handler.lock().unwrap();
panic.catch_panic(move || {
BlockQueue::verify(verification, engine, more_to_verify, ready_signal, deleting, empty)
}).unwrap()
})
.expect("Error starting block verification thread")
);
}
BlockQueue {
engine: engine,
panic_handler: panic_handler,
ready_signal: ready_signal.clone(),
more_to_verify: more_to_verify.clone(),
verification: verification.clone(),
@ -150,7 +164,7 @@ impl BlockQueue {
while lock.unverified.is_empty() && !deleting.load(AtomicOrdering::Relaxed) {
lock = wait.wait(lock).unwrap();
}
if deleting.load(AtomicOrdering::Relaxed) {
return;
}
@ -324,6 +338,12 @@ impl BlockQueue {
}
}
impl MayPanic<String> for BlockQueue {
fn on_panic<F>(&self, closure: F) where F: OnPanicListener<String> {
self.panic_handler.on_panic(closure);
}
}
impl Drop for BlockQueue {
fn drop(&mut self) {
self.clear();

31
ethcore/src/client.rs
View File

@ -17,6 +17,7 @@
//! Blockchain database client.
use util::*;
use util::panics::*;
use rocksdb::{Options, DB, DBCompactionStyle};
use blockchain::{BlockChain, BlockProvider, CacheSize};
use views::BlockView;
@ -157,7 +158,8 @@ pub struct Client {
state_db: Mutex<JournalDB>,
block_queue: RwLock<BlockQueue>,
report: RwLock<ClientReport>,
import_lock: Mutex<()>
import_lock: Mutex<()>,
panic_handler: SafeStringPanicHandler,
}
const HISTORY: u64 = 1000;
@ -198,19 +200,26 @@ impl Client {
let mut state_path = path.to_path_buf();
state_path.push("state");
let db = Arc::new(DB::open(&opts, state_path.to_str().unwrap()).unwrap());
let engine = Arc::new(try!(spec.to_engine()));
let mut state_db = JournalDB::new_with_arc(db.clone());
if state_db.is_empty() && engine.spec().ensure_db_good(&mut state_db) {
state_db.commit(0, &engine.spec().genesis_header().hash(), None).expect("Error commiting genesis state to state DB");
}
let block_queue = BlockQueue::new(engine.clone(), message_channel);
let panic_handler = StringPanicHandler::new_thread_safe();
let panic = panic_handler.clone();
block_queue.on_panic(move |t: &String| panic.lock().unwrap().notify_all(t));
Ok(Arc::new(Client {
chain: chain,
engine: engine.clone(),
engine: engine,
state_db: Mutex::new(state_db),
block_queue: RwLock::new(BlockQueue::new(engine, message_channel)),
block_queue: RwLock::new(block_queue),
report: RwLock::new(Default::default()),
import_lock: Mutex::new(()),
panic_handler: panic_handler
}))
}
@ -348,12 +357,12 @@ impl BlockChainClient for Client {
fn block_status(&self, hash: &H256) -> BlockStatus {
if self.chain.read().unwrap().is_known(&hash) {
BlockStatus::InChain
} else {
self.block_queue.read().unwrap().block_status(hash)
BlockStatus::InChain
} else {
self.block_queue.read().unwrap().block_status(hash)
}
}
fn block_total_difficulty(&self, hash: &H256) -> Option<U256> {
self.chain.read().unwrap().block_details(hash).map(|d| d.total_difficulty)
}
@ -423,3 +432,9 @@ impl BlockChainClient for Client {
}
}
}
impl MayPanic<String> for Client {
fn on_panic<F>(&self, closure: F) where F: OnPanicListener<String> {
self.panic_handler.on_panic(closure);
}
}

116
parity/main.rs
View File

@ -39,9 +39,11 @@ use rlog::{LogLevelFilter};
use env_logger::LogBuilder;
use ctrlc::CtrlC;
use util::*;
use util::panics::MayPanic;
use ethcore::client::*;
use ethcore::service::{ClientService, NetSyncMessage};
use ethcore::ethereum;
use ethcore::spec;
use ethcore::blockchain::CacheSize;
use ethsync::EthSync;
@ -84,7 +86,7 @@ fn setup_log(init: &str) {
#[cfg(feature = "rpc")]
fn setup_rpc_server(client: Arc<Client>, sync: Arc<EthSync>, url: &str) {
use rpc::v1::*;
let mut server = rpc::HttpServer::new(1);
server.add_delegate(Web3Client::new().to_delegate());
server.add_delegate(EthClient::new(client.clone()).to_delegate());
@ -97,46 +99,96 @@ fn setup_rpc_server(client: Arc<Client>, sync: Arc<EthSync>, url: &str) {
fn setup_rpc_server(_client: Arc<Client>, _sync: Arc<EthSync>, _url: &str) {
}
fn main() {
let args: Args = Args::docopt().decode().unwrap_or_else(|e| e.exit());
setup_log(&args.flag_logging);
unsafe { ::fdlimit::raise_fd_limit(); }
let spec = ethereum::new_frontier();
let init_nodes = match args.arg_enode.len() {
0 => spec.nodes().clone(),
_ => args.arg_enode.clone(),
};
let mut net_settings = NetworkConfiguration::new();
net_settings.boot_nodes = init_nodes;
match args.flag_address {
None => {
net_settings.listen_address = SocketAddr::from_str(args.flag_listen_address.as_ref()).expect("Invalid listen address given with --listen-address");
net_settings.public_address = SocketAddr::from_str(args.flag_public_address.as_ref()).expect("Invalid public address given with --public-address");
}
Some(ref a) => {
net_settings.public_address = SocketAddr::from_str(a.as_ref()).expect("Invalid listen/public address given with --address");
net_settings.listen_address = net_settings.public_address.clone();
struct Configuration {
args: Args
}
impl Configuration {
fn parse() -> Self {
Configuration {
args: Args::docopt().decode().unwrap_or_else(|e| e.exit())
}
}
let mut service = ClientService::start(spec, net_settings).unwrap();
let client = service.client().clone();
client.configure_cache(args.flag_cache_pref_size, args.flag_cache_max_size);
let sync = EthSync::register(service.network(), client);
if args.flag_jsonrpc {
setup_rpc_server(service.client(), sync.clone(), &args.flag_jsonrpc_url);
}
let io_handler = Arc::new(ClientIoHandler { client: service.client(), info: Default::default(), sync: sync });
service.io().register_handler(io_handler).expect("Error registering IO handler");
fn get_init_nodes(&self, spec: &spec::Spec) -> Vec<String> {
match self.args.arg_enode.len() {
0 => spec.nodes().clone(),
_ => self.args.arg_enode.clone(),
}
}
fn get_net_addresses(&self) -> (SocketAddr, SocketAddr) {
let listen_address;
let public_address;
match self.args.flag_address {
None => {
listen_address = SocketAddr::from_str(self.args.flag_listen_address.as_ref()).expect("Invalid listen address given with --listen-address");
public_address = SocketAddr::from_str(self.args.flag_public_address.as_ref()).expect("Invalid public address given with --public-address");
}
Some(ref a) => {
public_address = SocketAddr::from_str(a.as_ref()).expect("Invalid listen/public address given with --address");
listen_address = public_address.clone();
}
};
(listen_address, public_address)
}
}
fn wait_for_exit(client: Arc<Client>) {
let exit = Arc::new(Condvar::new());
// Handle possible exits
let e = exit.clone();
CtrlC::set_handler(move || { e.notify_all(); });
let e = exit.clone();
client.on_panic(move |_t: &String| { e.notify_all(); });
// Wait for signal
let mutex = Mutex::new(());
let _ = exit.wait(mutex.lock().unwrap()).unwrap();
}
fn main() {
let conf = Configuration::parse();
let spec = ethereum::new_frontier();
// Setup logging
setup_log(&conf.args.flag_logging);
// Raise fdlimit
unsafe { ::fdlimit::raise_fd_limit(); }
// Configure network
let init_nodes = conf.get_init_nodes(&spec);
let (listen, public) = conf.get_net_addresses();
let mut net_settings = NetworkConfiguration::new();
net_settings.boot_nodes = init_nodes;
net_settings.listen_address = listen;
net_settings.public_address = public;
// Build client
let mut service = ClientService::start(spec, net_settings).unwrap();
let client = service.client().clone();
client.configure_cache(conf.args.flag_cache_pref_size, conf.args.flag_cache_max_size);
// Sync
let sync = EthSync::register(service.network(), client);
// Setup rpc
if conf.args.flag_jsonrpc {
setup_rpc_server(service.client(), sync.clone(), &conf.args.flag_jsonrpc_url);
}
// Register IO handler
let io_handler = Arc::new(ClientIoHandler {
client: service.client(),
info: Default::default(),
sync: sync
});
service.io().register_handler(io_handler).expect("Error registering IO handler");
// Handle exit
wait_for_exit(service.client());
}
struct Informant {
chain_info: RwLock<Option<BlockChainInfo>>,
cache_info: RwLock<Option<CacheSize>>,
@ -200,7 +252,7 @@ struct ClientIoHandler {
}
impl IoHandler<NetSyncMessage> for ClientIoHandler {
fn initialize(&self, io: &IoContext<NetSyncMessage>) {
fn initialize(&self, io: &IoContext<NetSyncMessage>) {
io.register_timer(INFO_TIMER, 5000).expect("Error registering timer");
}

20
util/src/io/mod.rs
View File

@ -31,16 +31,16 @@
//!
//! impl IoHandler<MyMessage> for MyHandler {
//! fn initialize(&self, io: &IoContext<MyMessage>) {
//! io.register_timer(0, 1000).unwrap();
//! }
//! io.register_timer(0, 1000).unwrap();
//! }
//!
//! fn timeout(&self, _io: &IoContext<MyMessage>, timer: TimerToken) {
//! println!("Timeout {}", timer);
//! }
//! fn timeout(&self, _io: &IoContext<MyMessage>, timer: TimerToken) {
//! println!("Timeout {}", timer);
//! }
//!
//! fn message(&self, _io: &IoContext<MyMessage>, message: &MyMessage) {
//! println!("Message {}", message.data);
//! }
//! fn message(&self, _io: &IoContext<MyMessage>, message: &MyMessage) {
//! println!("Message {}", message.data);
//! }
//! }
//!
//! fn main () {
@ -70,7 +70,7 @@ impl<Message> From<::mio::NotifyError<service::IoMessage<Message>>> for IoError
}
}
/// Generic IO handler.
/// Generic IO handler.
/// All the handler function are called from within IO event loop.
/// `Message` type is used as notification data
pub trait IoHandler<Message>: Send + Sync where Message: Send + Sync + Clone + 'static {
@ -82,7 +82,7 @@ pub trait IoHandler<Message>: Send + Sync where Message: Send + Sync + Clone + '
fn message(&self, _io: &IoContext<Message>, _message: &Message) {}
/// Called when an IO stream gets closed
fn stream_hup(&self, _io: &IoContext<Message>, _stream: StreamToken) {}
/// Called when an IO stream can be read from
/// Called when an IO stream can be read from
fn stream_readable(&self, _io: &IoContext<Message>, _stream: StreamToken) {}
/// Called when an IO stream can be written to
fn stream_writable(&self, _io: &IoContext<Message>, _stream: StreamToken) {}

18
util/src/io/service.rs
View File

@ -25,6 +25,7 @@ use io::{IoError, IoHandler};
use arrayvec::*;
use crossbeam::sync::chase_lev;
use io::worker::{Worker, Work, WorkType};
use panics::*;
/// Timer ID
pub type TimerToken = usize;
@ -164,7 +165,7 @@ impl<Message> IoManager<Message> where Message: Send + Sync + Clone + 'static {
let num_workers = 4;
let work_ready_mutex = Arc::new(Mutex::new(()));
let work_ready = Arc::new(Condvar::new());
let workers = (0..num_workers).map(|i|
let workers = (0..num_workers).map(|i|
Worker::new(i, stealer.clone(), IoChannel::new(event_loop.channel()), work_ready.clone(), work_ready_mutex.clone())).collect();
let mut io = IoManager {
@ -306,19 +307,32 @@ impl<Message> IoChannel<Message> where Message: Send + Clone {
/// General IO Service. Starts an event loop and dispatches IO requests.
/// 'Message' is a notification message type
pub struct IoService<Message> where Message: Send + Sync + Clone + 'static {
panic_handler: SafeStringPanicHandler,
thread: Option<JoinHandle<()>>,
host_channel: Sender<IoMessage<Message>>,
}
impl<Message> MayPanic<String> for IoService<Message> where Message: Send + Sync + Clone + 'static {
fn on_panic<F>(&self, closure: F) where F: OnPanicListener<String> {
self.panic_handler.on_panic(closure);
}
}
impl<Message> IoService<Message> where Message: Send + Sync + Clone + 'static {
/// Starts IO event loop
pub fn start() -> Result<IoService<Message>, UtilError> {
let panic_handler = StringPanicHandler::new_thread_safe();
let mut event_loop = EventLoop::new().unwrap();
let channel = event_loop.channel();
let panic = panic_handler.clone();
let thread = thread::spawn(move || {
IoManager::<Message>::start(&mut event_loop).unwrap(); //TODO:
let mut panic = panic.lock().unwrap();
panic.catch_panic(move || {
IoManager::<Message>::start(&mut event_loop).unwrap();
}).unwrap()
});
Ok(IoService {
panic_handler: panic_handler,
thread: Some(thread),
host_channel: channel
})

30
util/src/io/worker.rs
View File

@ -21,6 +21,7 @@ use std::sync::atomic::{AtomicBool, Ordering as AtomicOrdering};
use crossbeam::sync::chase_lev;
use io::service::{HandlerId, IoChannel, IoContext};
use io::{IoHandler};
use panics::*;
pub enum WorkType<Message> {
Readable,
@ -43,32 +44,41 @@ pub struct Worker {
thread: Option<JoinHandle<()>>,
wait: Arc<Condvar>,
deleting: Arc<AtomicBool>,
panic_handler: SafeStringPanicHandler,
}
impl Worker {
/// Creates a new worker instance.
pub fn new<Message>(index: usize,
stealer: chase_lev::Stealer<Work<Message>>,
pub fn new<Message>(index: usize,
stealer: chase_lev::Stealer<Work<Message>>,
channel: IoChannel<Message>,
wait: Arc<Condvar>,
wait_mutex: Arc<Mutex<()>>) -> Worker
wait_mutex: Arc<Mutex<()>>) -> Worker
where Message: Send + Sync + Clone + 'static {
let panic_handler = StringPanicHandler::new_thread_safe();
let deleting = Arc::new(AtomicBool::new(false));
let mut worker = Worker {
panic_handler: panic_handler.clone(),
thread: None,
wait: wait.clone(),
deleting: deleting.clone(),
};
let panic_handler = panic_handler.clone();
worker.thread = Some(thread::Builder::new().name(format!("IO Worker #{}", index)).spawn(
move || Worker::work_loop(stealer, channel.clone(), wait, wait_mutex.clone(), deleting))
move || {
let mut panic = panic_handler.lock().unwrap();
panic.catch_panic(move || {
Worker::work_loop(stealer, channel.clone(), wait, wait_mutex.clone(), deleting)
}).unwrap()
})
.expect("Error creating worker thread"));
worker
}
fn work_loop<Message>(stealer: chase_lev::Stealer<Work<Message>>,
channel: IoChannel<Message>, wait: Arc<Condvar>,
wait_mutex: Arc<Mutex<()>>,
deleting: Arc<AtomicBool>)
channel: IoChannel<Message>, wait: Arc<Condvar>,
wait_mutex: Arc<Mutex<()>>,
deleting: Arc<AtomicBool>)
where Message: Send + Sync + Clone + 'static {
while !deleting.load(AtomicOrdering::Relaxed) {
{
@ -105,6 +115,12 @@ impl Worker {
}
}
impl MayPanic<String> for Worker {
fn on_panic<F>(&self, closure: F) where F: OnPanicListener<String> {
self.panic_handler.on_panic(closure);
}
}
impl Drop for Worker {
fn drop(&mut self) {
self.deleting.store(true, AtomicOrdering::Relaxed);

3
util/src/lib.rs
View File

@ -21,7 +21,8 @@
#![feature(plugin)]
#![plugin(clippy)]
#![allow(needless_range_loop, match_bool)]
#![feature(std_panic, recover)]
#![feature(catch_panic)]
//! Ethcore-util library
//!
//! ### Rust version:

160
util/src/panics.rs
View File

@ -17,10 +17,9 @@
//! Panic utilities
use std::thread;
use std::panic;
use std::sync::Mutex;
use std::any::Any;
use std::ops::DerefMut;
use std::any::Any;
use std::sync::{Arc, Mutex};
pub trait OnPanicListener<T>: Send + Sync + 'static {
fn call(&mut self, arg: &T);
@ -33,26 +32,37 @@ impl<F, T> OnPanicListener<T> for F
}
}
pub trait ArgsConverter<T> {
pub trait ArgsConverter<T> : Send + Sync {
fn convert(&self, t: &Box<Any + Send>) -> Option<T>;
}
pub trait MayPanic<T> {
fn on_panic<F>(&mut self, closure: F)
fn on_panic<F>(&self, closure: F)
where F: OnPanicListener<T>;
}
pub trait PanicHandler<T, C: ArgsConverter<T>> : MayPanic<T>{
fn new(converter: C) -> Self;
fn with_converter(converter: C) -> Self;
fn catch_panic<G, R>(&mut self, g: G) -> thread::Result<R>
where G: FnOnce() -> R + panic::RecoverSafe;
where G: FnOnce() -> R + Send + 'static;
fn notify_all(&mut self, &T);
}
pub type SafeStringPanicHandler = Arc<Mutex<StringPanicHandler>>;
impl MayPanic<String> for SafeStringPanicHandler {
fn on_panic<F>(&self, closure: F) where F: OnPanicListener<String> {
self.lock().unwrap().on_panic(closure);
}
}
pub struct StringConverter;
impl ArgsConverter<String> for StringConverter {
fn convert(&self, t: &Box<Any + Send>) -> Option<String> {
t.downcast_ref::<&'static str>().map(|t| t.clone().to_owned())
let as_str = t.downcast_ref::<&'static str>().map(|t| t.clone().to_owned());
let as_string = t.downcast_ref::<String>().cloned();
as_str.or(as_string)
}
}
@ -62,86 +72,152 @@ pub struct BasePanicHandler<T, C>
listeners: Mutex<Vec<Box<OnPanicListener<T>>>>
}
impl<T, C> BasePanicHandler<T, C>
where C: ArgsConverter<T>, T: 'static {
fn notify_all(&mut self, res: Option<T>) {
if let None = res {
return;
}
let r = res.unwrap();
let mut listeners = self.listeners.lock().unwrap();
for listener in listeners.deref_mut() {
listener.call(&r);
}
}
}
impl<T, C> PanicHandler<T, C> for BasePanicHandler<T, C>
where C: ArgsConverter<T>, T: 'static {
fn new(converter: C) -> Self {
fn with_converter(converter: C) -> Self {
BasePanicHandler {
converter: converter,
listeners: Mutex::new(vec![])
}
}
fn catch_panic<G, R>(&mut self, g: G) -> thread::Result<R>
where G: FnOnce() -> R + panic::RecoverSafe {
let result = panic::recover(g);
#[allow(deprecated)]
// TODO [todr] catch_panic is deprecated but panic::recover has different bounds (not allowing mutex)
fn catch_panic<G, R>(&mut self, g: G) -> thread::Result<R> where G: FnOnce() -> R + Send + 'static {
let result = thread::catch_panic(g);
println!("After calling function");
if let Err(ref e) = result {
let res = self.converter.convert(e);
println!("Got error. Notifying");
self.notify_all(res);
if let Err(ref e) = result {
let res = self.converter.convert(e);
if let Some(r) = res {
self.notify_all(&r);
}
result
}
result
}
fn notify_all(&mut self, r: &T) {
let mut listeners = self.listeners.lock().unwrap();
for listener in listeners.deref_mut() {
listener.call(r);
}
}
}
impl<T, C> MayPanic<T> for BasePanicHandler<T, C>
where C: ArgsConverter<T>, T: 'static {
fn on_panic<F>(&mut self, closure: F)
fn on_panic<F>(&self, closure: F)
where F: OnPanicListener<T> {
self.listeners.lock().unwrap().push(Box::new(closure));
}
}
pub struct StringPanicHandler {
handler: BasePanicHandler<String, StringConverter>
}
impl StringPanicHandler {
pub fn new_thread_safe() -> SafeStringPanicHandler {
Arc::new(Mutex::new(Self::new()))
}
pub fn new () -> Self {
Self::with_converter(StringConverter)
}
}
impl PanicHandler<String, StringConverter> for StringPanicHandler {
fn with_converter(converter: StringConverter) -> Self {
StringPanicHandler {
handler: BasePanicHandler::with_converter(converter)
}
}
fn catch_panic<G, R>(&mut self, g: G) -> thread::Result<R> where G: FnOnce() -> R + Send + 'static {
self.handler.catch_panic(g)
}
fn notify_all(&mut self, r: &String) {
self.handler.notify_all(r);
}
}
impl MayPanic<String> for StringPanicHandler {
fn on_panic<F>(&self, closure: F)
where F: OnPanicListener<String> {
self.handler.on_panic(closure)
}
}
#[test]
fn should_notify_listeners_about_panic () {
use std::sync::{Arc, RwLock};
use std::sync::RwLock;
// given
let invocations = Arc::new(RwLock::new(vec![]));
let i = invocations.clone();
let mut p = BasePanicHandler::new(StringConverter);
let mut p = StringPanicHandler::new();
p.on_panic(move |t: &String| i.write().unwrap().push(t.clone()));
// when
p.catch_panic(|| panic!("Panic!"));
p.catch_panic(|| panic!("Panic!")).unwrap_err();
// then
assert!(invocations.read().unwrap()[0] == "Panic!");
}
#[test]
fn should_notify_listeners_about_panic_when_string_is_dynamic () {
use std::sync::RwLock;
// given
let invocations = Arc::new(RwLock::new(vec![]));
let i = invocations.clone();
let mut p = StringPanicHandler::new();
p.on_panic(move |t: &String| i.write().unwrap().push(t.clone()));
// when
p.catch_panic(|| panic!("Panic: {}", 1)).unwrap_err();
// then
assert!(invocations.read().unwrap()[0] == "Panic: 1");
}
#[test]
fn should_notify_listeners_about_panic_in_other_thread () {
use std::thread;
use std::sync::{Arc, RwLock};
use std::sync::RwLock;
// given
let invocations = Arc::new(RwLock::new(vec![]));
let i = invocations.clone();
let mut p = BasePanicHandler::new(StringConverter);
let mut p = StringPanicHandler::new();
p.on_panic(move |t: &String| i.write().unwrap().push(t.clone()));
// when
let t = thread::spawn(move ||
p.catch_panic(|| panic!("Panic!"))
p.catch_panic(|| panic!("Panic!")).unwrap()
);
t.join();
t.join().unwrap_err();
// then
assert!(invocations.read().unwrap()[0] == "Panic!");
}
#[test]
fn should_forward_panics () {
use std::sync::RwLock;
// given
let invocations = Arc::new(RwLock::new(vec![]));
let i = invocations.clone();
let mut p = StringPanicHandler::new();
p.on_panic(move |t: &String| i.write().unwrap().push(t.clone()));
let mut p2 = StringPanicHandler::new();
p2.on_panic(move |t: &String| p.notify_all(t));
// when
p2.catch_panic(|| panic!("Panic!")).unwrap_err();
// then
assert!(invocations.read().unwrap()[0] == "Panic!");