Make cargo-codspeed build targets to different directories between walltime and instrumented

crates/cargo-codspeed/src/app.rs

@@ -14,8 +14,6 @@ struct Cli {
 
     /// The measurement tool to use for measuring performance.
     /// Automatically set to `walltime` on macro runners
-    // This is an Option even if MeasurementMode has a default because
-    // the default is dynamic and this would mislead the user
     #[arg(short, long, global = true, env = "CODSPEED_RUNNER_MODE")]
     measurement_mode: Option<MeasurementMode>,
 

crates/cargo-codspeed/src/build.rs

@@ -174,7 +174,7 @@ pub fn build_benches(
         );
     }
 
-    let codspeed_target_dir = get_codspeed_target_dir(metadata);
+    let codspeed_target_dir = get_codspeed_target_dir(metadata, measurement_mode);
     let built_bench_count = built_benches.len();
 
     // Create and clear packages codspeed target directories

crates/cargo-codspeed/src/helpers.rs

@@ -1,9 +1,13 @@
-use crate::prelude::*;
+use crate::{measurement_mode::MeasurementMode, prelude::*};
 use cargo_metadata::Metadata;
 use std::path::{Path, PathBuf};
 
-pub fn get_codspeed_target_dir(metadata: &Metadata) -> PathBuf {
-    metadata.target_directory.join("codspeed").into()
+pub fn get_codspeed_target_dir(metadata: &Metadata, measurement_mode: MeasurementMode) -> PathBuf {
+    metadata
+        .target_directory
+        .join("codspeed")
+        .join(measurement_mode.to_string())
+        .into()
 }
 
 pub fn clear_dir<P>(dir: P) -> Result<()>

crates/cargo-codspeed/src/measurement_mode.rs

@@ -1,20 +1,24 @@
 use clap::ValueEnum;
 use serde::Serialize;
-use std::env;
+use std::fmt;
 
-#[derive(Debug, Clone, ValueEnum, Serialize, PartialEq, Eq)]
+#[derive(Debug, Clone, Copy, ValueEnum, Serialize, PartialEq, Eq, Default)]
 #[serde(rename_all = "lowercase")]
 pub enum MeasurementMode {
-    Walltime,
+    #[default]
     Instrumentation,
+    Walltime,
 }
 
-impl Default for MeasurementMode {
-    fn default() -> Self {
-        if env::var("CODSPEED_ENV").is_ok() {
-            MeasurementMode::Instrumentation
-        } else {
-            MeasurementMode::Walltime
-        }
+impl fmt::Display for MeasurementMode {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(
+            f,
+            "{}",
+            match self {
+                MeasurementMode::Instrumentation => "instrumentation",
+                MeasurementMode::Walltime => "walltime",
+            }
+        )
     }
 }

crates/cargo-codspeed/src/run.rs

@@ -99,7 +99,7 @@ pub fn run_benches(
     filters: Filters,
     measurement_mode: MeasurementMode,
 ) -> Result<()> {
-    let codspeed_target_dir = get_codspeed_target_dir(metadata);
+    let codspeed_target_dir = get_codspeed_target_dir(metadata, measurement_mode);
     let workspace_root = metadata.workspace_root.as_std_path();
     if measurement_mode == MeasurementMode::Walltime {
         clear_raw_walltime_data(workspace_root)?;

crates/codspeed/src/walltime.rs

@@ -65,6 +65,8 @@ pub fn collect_raw_walltime_results(
     data.dump_to_results(&workspace_root, scope);
 }
 
+// FIXME: This assumes that the cargo target dir is `target`, and duplicates information with
+// `cargo-codspeed::helpers::get_codspeed_target_dir`
 pub fn get_raw_result_dir_from_workspace_root(workspace_root: &Path) -> PathBuf {
     workspace_root
         .join("target")