Disable the `deadlock_detection` feature by default (#195)

* Disable the `deadlock_detection` feature by default

Fixes conflicts with any packages that enable parking_lot's `send_guard` feature

* move testbot deadlock detection to a function and add additional comments

---------

Co-authored-by: mat <git@matdoes.dev>

3 files changed, 30 insertions, 28 deletions

diff --git a/azalea/Cargo.toml b/azalea/Cargo.toml
index a658c3a8..63e84f54 100644
--- a/azalea/Cargo.toml
+++ b/azalea/Cargo.toml
@@ -8,7 +8,7 @@ repository = { workspace = true }
 
 [package.metadata.release]
 pre-release-replacements = [
-    { file = "README.md", search = "`azalea = \"[a-z0-9\\.-]+\"`", replace = "`azalea = \"{{version}}\"`" },
+  { file = "README.md", search = "`azalea = \"[a-z0-9\\.-]+\"`", replace = "`azalea = \"{{version}}\"`" },
 ]
 
 [dependencies]
@@ -37,7 +37,7 @@ futures = { workspace = true }
 futures-lite = { workspace = true }
 nohash-hasher = { workspace = true }
 num-traits = { workspace = true }
-parking_lot = { workspace = true, features = ["deadlock_detection"] }
+parking_lot = { workspace = true }
 priority-queue = { workspace = true }
 rustc-hash = { workspace = true }
 serde = { workspace = true, optional = true }
@@ -48,6 +48,7 @@ uuid = { workspace = true }
 
 [dev-dependencies]
 criterion = { workspace = true }
+parking_lot = { workspace = true, features = ["deadlock_detection"] }
 rand = { workspace = true }
 
 [features]
diff --git a/azalea/README.md b/azalea/README.md
index e7f52cd6..a135add4 100755
--- a/azalea/README.md
+++ b/azalea/README.md
@@ -99,7 +99,7 @@ Note: If you get a `SetLoggerError`, it's because you have multiple loggers. Aza
 
 ## Deadlocks
 
-If your code is simply hanging, it might be a deadlock. Copy the deadlock block in [`azalea/examples/testbot.rs`](https://github.com/azalea-rs/azalea/blob/main/azalea/examples/testbot/main.rs) to the beginning of your code and it'll print a long backtrace if a deadlock is detected.
+If your code is simply hanging, it might be a deadlock. Enable `parking_lot`'s `deadlock_detection` feature and copy the deadlock block in [`azalea/examples/testbot.rs`](https://github.com/azalea-rs/azalea/blob/main/azalea/examples/testbot/main.rs) to the beginning of your code and it'll print a long backtrace if a deadlock is detected.
 
 ## Backtraces
 
diff --git a/azalea/examples/testbot/main.rs b/azalea/examples/testbot/main.rs
index e7d68d5e..9c8d1085 100644
--- a/azalea/examples/testbot/main.rs
+++ b/azalea/examples/testbot/main.rs
@@ -14,8 +14,8 @@
 mod commands;
 pub mod killaura;
 
-use std::sync::Arc;
 use std::time::Duration;
+use std::{sync::Arc, thread};
 
 use azalea::brigadier::command_dispatcher::CommandDispatcher;
 use azalea::ecs::prelude::*;
@@ -37,30 +37,7 @@ const PATHFINDER_DEBUG_PARTICLES: bool = false;
 
 #[tokio::main]
 async fn main() {
-    {
-        use std::thread;
-        use std::time::Duration;
-
-        use parking_lot::deadlock;
-
-        // Create a background thread which checks for deadlocks every 10s
-        thread::spawn(move || loop {
-            thread::sleep(Duration::from_secs(10));
-            let deadlocks = deadlock::check_deadlock();
-            if deadlocks.is_empty() {
-                continue;
-            }
-
-            println!("{} deadlocks detected", deadlocks.len());
-            for (i, threads) in deadlocks.iter().enumerate() {
-                println!("Deadlock #{i}");
-                for t in threads {
-                    println!("Thread Id {:#?}", t.thread_id());
-                    println!("{:#?}", t.backtrace());
-                }
-            }
-        });
-    }
+    thread::spawn(deadlock_detection_thread);
 
     let account = Account::offline(USERNAME);
 
@@ -85,6 +62,30 @@ async fn main() {
         .unwrap();
 }
 
+/// Runs a loop that checks for deadlocks every 10 seconds.
+///
+/// Note that this requires the `deadlock_detection` parking_lot feature to be
+/// enabled, which is only enabled in azalea by default when running in debug
+/// mode.
+fn deadlock_detection_thread() {
+    loop {
+        thread::sleep(Duration::from_secs(10));
+        let deadlocks = parking_lot::deadlock::check_deadlock();
+        if deadlocks.is_empty() {
+            continue;
+        }
+
+        println!("{} deadlocks detected", deadlocks.len());
+        for (i, threads) in deadlocks.iter().enumerate() {
+            println!("Deadlock #{i}");
+            for t in threads {
+                println!("Thread Id {:#?}", t.thread_id());
+                println!("{:#?}", t.backtrace());
+            }
+        }
+    }
+}
+
 #[derive(Clone, Copy, Debug, PartialEq, Eq, Default)]
 pub enum BotTask {
     #[default]