cli: default RUST_LOG if it's not set

src/main.rs

@@ -2,6 +2,7 @@
 //
 // SPDX-License-Identifier: EUPL-1.1
 
+use std::env;
 use std::io::{self, IsTerminal};
 use std::process::ExitCode;
 use std::{error::Error as StdError, sync::Arc};
@@ -12,6 +13,13 @@ use tracing_subscriber::util::SubscriberInitExt;
 use tracing_subscriber::{EnvFilter, layer::SubscriberExt};
 
 fn main_wrapped() -> Result<(), Box<dyn StdError + Send + Sync + 'static>> {
+    // Default RUST_LOG to warn if it's not specified.
+    if let None = env::var_os("RUST_LOG") {
+        unsafe {
+            env::set_var("RUST_LOG", "warn");
+        }
+    }
+
     let args = Arc::new(dynix::Args::parse());
 
     let success = dynix::_CLI_ENABLE_COLOR.set(match args.color {
@@ -47,6 +55,6 @@ fn main() -> ExitCode {
         Err(e) => {
             eprintln!("dynix: error: {}", e);
             ExitCode::FAILURE
-        }
+        },
     }
 }