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use std::{io, str, sync::Mutex};
use tracing::subscriber::set_global_default;
use tracing_subscriber::{layer::SubscriberExt, registry};
use tracing_tree::HierarchicalLayer;
struct RecursiveWriter(Mutex<Vec<u8>>);
impl io::Write for &RecursiveWriter {
fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
self.0.lock().unwrap().extend(buf);
tracing::error!("Nobody expects the Spanish Inquisition");
Ok(buf.len())
}
fn flush(&mut self) -> io::Result<()> {
tracing::error!("Nobody expects the Spanish Inquisition");
Ok(())
}
}
/// This test checks that if `tracing` events happen during processing of
/// `on_event`, the library does not deadlock.
#[test]
fn recursive_event() {
static WRITER: RecursiveWriter = RecursiveWriter(Mutex::new(Vec::new()));
let subscriber = registry().with(HierarchicalLayer::new(2).with_writer(|| &WRITER));
// This has to be its own integration test because we can't just set a
// global default like this otherwise and not expect everything else to
// break.
set_global_default(subscriber).unwrap();
tracing::error!("We can never expect the unexpected.");
let output = WRITER.0.lock().unwrap();
let output = str::from_utf8(&output).unwrap();
// If this test finished we're happy. Let's just also check that we did
// in fact log _something_ and that the logs from within the writer did
// not actually go through.
assert!(output.contains("We can never expect the unexpected."));
assert!(!output.contains("Nobody expects the Spanish Inquisition"));
}
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