fix(cli): Remove __ prefix

Author: epage

src/bin/cargo/main.rs

@@ -54,9 +54,9 @@ fn setup_logger() -> Option<tracing_chrome::FlushGuard> {
         .with_filter(env);
 
     let (profile_layer, profile_guard) =
-        if env_to_bool(std::env::var_os("__CARGO_LOG_PROFILE").as_deref()) {
+        if env_to_bool(std::env::var_os("CARGO_LOG_PROFILE").as_deref()) {
             let capture_args =
-                env_to_bool(std::env::var_os("__CARGO_LOG_PROFILE_CAPTURE_ARGS").as_deref());
+                env_to_bool(std::env::var_os("CARGO_LOG_PROFILE_CAPTURE_ARGS").as_deref());
             let (layer, guard) = tracing_chrome::ChromeLayerBuilder::new()
                 .include_args(capture_args)
                 .build();

src/doc/contrib/src/tests/profiling.md

@@ -6,18 +6,20 @@ Cargo leverages [tracing](https://crates.io/crates/tracing)
 as a basic, hierarchical built-in profiler.
 
 Environment variables:
-- `__CARGO_LOG_PROFILE=<true|1>`: log tracing events to a file in the current working directory
-- `__CARGO_LOG_PROFILE_CAPTURE_ARGS=<true|1>`: include arguments in the events
+- `CARGO_LOG_PROFILE=<true|1>`: log tracing events to a file in the current working directory
+- `CARGO_LOG_PROFILE_CAPTURE_ARGS=<true|1>`: include arguments in the events
 
 At process exit, your trace will be in a file like `trace-1668480819035032.json`.
 Open that file with [ui.perfetto.dev](https://ui.perfetto.dev) (or chrome://tracing) to browse your trace.
 
 Example:
 ```console
 $ # Output first three levels of profiling info
-$ __CARGO_LOG_PROFILE=true cargo generate-lockfile
+$ CARGO_LOG_PROFILE=true cargo generate-lockfile
 ```
 
+**Note:** This is intended for the development of cargo and there are no compatibility guarantees on this functionality.
+
 ## Benchmarking
 
 ### Benchsuite