Fix system order ambiguities (#74)

* start fixing stuff where systems run in the wrong order

* fix ordering ambiguity

* add debugging guide

* some fixes

* fix panic for swarms

* fix some warnings

1 files changed, 21 insertions, 0 deletions

diff --git a/azalea/README.md b/azalea/README.md
index a9c44461..21be566a 100755
--- a/azalea/README.md
+++ b/azalea/README.md
@@ -83,4 +83,25 @@ Also note that just because something is an entity in the ECS doesn't mean that
 
 See the [Bevy Cheatbook](https://bevy-cheatbook.github.io/programming/ecs-intro.html) to learn more about Bevy ECS (and the ECS paradigm in general).
 
+# Debugging
+
+Azalea uses several relatively complex features of Rust, which may make debugging certain issues more tricky if you're not familiar with them.
+
+## Logging
+
+One of the most useful tools for debugging issues is logging. The default log level is `info`, but you can make it show more or less information by changing the log level. Enabling logging is done with `RUST_LOG=debug cargo run` on Linux/bash or `set RUST_LOG=debug && cargo run` on Windows. The log levels are `trace`, `debug`, `info`, `warn`, and `error`, in ascending priority.
+
+If it's a crash/panic and you believe it has to do with parsing a packet, you might want to set the level to `trace` since that'll make it show the first few hundred bytes of every packet received. This may produce a lot of logs, so pipe it into a file with `&> azalea.log` (on Linux).
+
+Note: If you get a `SetLoggerError`, it's because you have multiple loggers. Azalea comes with a logger by default, see [`bevy_log`] for more information.
+
+## Deadlocks
+
+If your code is simply hanging, it might be a deadlock. Copy the deadlock block in [`azalea/examples/testbot.rs`](https://github.com/mat-1/azalea/blob/main/azalea/examples/testbot.rs) to the beginning of your code and it'll print a long backtrace if a deadlock is detected.
+
+## Backtraces
+
+Backtraces are also useful, though they're sometimes hard to read and don't always contain the actual location of the error. Run your code with `RUST_BACKTRACE=1` to enable full backtraces. If it's very long, often searching for the keyword "azalea" will help you filter out unrelated things and find the actual source of the issue.
+
 [`azalea_client`]: https://docs.rs/azalea-client
+[`bevy_log`]: https://docs.rs/bevy_log