Make tracing Optional for bevy_utils

crates/bevy_utils/Cargo.toml

@@ -9,23 +9,26 @@ license = "MIT OR Apache-2.0"
 keywords = ["bevy"]
 
 [features]
-default = ["std", "serde"]
+default = ["std", "serde", "tracing"]
 std = [
   "alloc",
-  "tracing/std",
+  "log/std",
   "ahash/std",
   "dep:thread_local",
   "ahash/runtime-rng",
+  "tracing?/std",
 ]
 alloc = ["hashbrown/default"]
+tracing = ["dep:tracing"]
 detailed_trace = []
 serde = ["hashbrown/serde"]
 
 [dependencies]
 ahash = { version = "0.8.7", default-features = false, features = [
   "compile-time-rng",
 ] }
-tracing = { version = "0.1", default-features = false }
+log = { version = "0.4", default-features = false }
+tracing = { version = "0.1", default-features = false, optional = true }
 hashbrown = { version = "0.14.2", default-features = false }
 bevy_utils_proc_macros = { version = "0.15.0-dev", path = "macros" }
 thread_local = { version = "1.0", optional = true }

crates/bevy_utils/src/lib.rs

@@ -42,8 +42,16 @@ pub use hashbrown;
 #[cfg(feature = "std")]
 pub use parallel_queue::*;
 pub use time::*;
+
+#[cfg(feature = "tracing")]
 pub use tracing;
 
+#[cfg(not(feature = "tracing"))]
+// In cases where the tracing crate cannot be used, we can instead rely on log to
+// provide most of the required functionality.
+// Exporting log as tracing allows this decision to have minimal impact on consumers.
+pub use log as tracing;
+
 #[cfg(feature = "alloc")]
 use alloc::boxed::Box;