Merge #6354

6354: Add tracing to main rust-analyzer binary r=flodiebold a=flodiebold

This makes `CHALK_DEBUG` logging work again e.g. when running `analysis-stats`, which is very helpful for debugging.

This change shouldn't regress compile times at all. The reason for that is that chalk-solve already pulls in these crates, and while that's behind a feature (mostly for our benefit, I think) we never actually disabled that feature 😅 So alternatively, we could disable the feature and maybe get an improvement in compile times. In my test I just did to see the impact of that, this PR actually compiled faster than the one just removing tracing though, so it's probably not a big deal.

Co-authored-by: Florian Diebold <florian.diebold@freiheit.com>

Cargo.lock

@@ -1372,6 +1372,9 @@ dependencies = [
  "text_edit",
  "threadpool",
  "toolchain",
+ "tracing",
+ "tracing-subscriber",
+ "tracing-tree",
  "tt",
  "vfs",
  "vfs-notify",

crates/hir_ty/Cargo.toml

@@ -17,7 +17,7 @@ ena = "0.14.0"
 log = "0.4.8"
 rustc-hash = "1.1.0"
 scoped-tls = "1"
-chalk-solve = "0.34"
+chalk-solve = { version = "0.34", default-features = false }
 chalk-ir = "0.34"
 chalk-recursive = "0.34"
 

crates/rust-analyzer/Cargo.toml

@@ -32,6 +32,9 @@ threadpool = "1.7.1"
 rayon = "1.5"
 mimalloc = { version = "0.1.19", default-features = false, optional = true }
 lsp-server = "0.4.0"
+tracing = "0.1"
+tracing-subscriber = { version = "0.2", default-features = false, features = ["env-filter", "registry"] }
+tracing-tree = { version = "0.1.4" }
 
 stdx = { path = "../stdx", version = "0.0.0" }
 flycheck = { path = "../flycheck", version = "0.0.0" }

crates/rust-analyzer/src/bin/main.rs

@@ -68,10 +68,32 @@ fn setup_logging(log_file: Option<PathBuf>) -> Result<()> {
     let filter = env::var("RA_LOG").ok();
     logger::Logger::new(log_file, filter.as_deref()).install();
 
+    tracing_setup::setup_tracing()?;
+
     profile::init();
     Ok(())
 }
 
+mod tracing_setup {
+    use tracing::subscriber;
+    use tracing_subscriber::layer::SubscriberExt;
+    use tracing_subscriber::EnvFilter;
+    use tracing_subscriber::Registry;
+    use tracing_tree::HierarchicalLayer;
+
+    pub fn setup_tracing() -> super::Result<()> {
+        let filter = EnvFilter::from_env("CHALK_DEBUG");
+        let layer = HierarchicalLayer::default()
+            .with_indent_lines(true)
+            .with_ansi(false)
+            .with_indent_amount(2)
+            .with_writer(std::io::stderr);
+        let subscriber = Registry::default().with(filter).with(layer);
+        subscriber::set_global_default(subscriber)?;
+        Ok(())
+    }
+}
+
 fn run_server() -> Result<()> {
     log::info!("server will start");