Actually make --perf imply -j=1, review comments

Author: blyxyas

lintcheck/src/config.rs

@@ -2,6 +2,7 @@ use clap::{Parser, Subcommand, ValueEnum};
 use std::num::NonZero;
 use std::path::PathBuf;
 
+#[allow(clippy::struct_excessive_bools)]
 #[derive(Parser, Clone, Debug)]
 #[command(args_conflicts_with_subcommands = true)]
 pub(crate) struct LintcheckConfig {
@@ -11,6 +12,8 @@ pub(crate) struct LintcheckConfig {
         short = 'j',
         value_name = "N",
         default_value_t = 0,
+        default_value_if("perf", "true", Some("1")), // Limit jobs to 1 when benchmarking
+        required = false,
         hide_default_value = true
     )]
     pub max_jobs: usize,

lintcheck/src/main.rs

@@ -131,6 +131,7 @@ impl Crate {
                 "--",
                 "cargo",
             ]);
+            cmd.env("CARGO_PROFILE_RELEASE_DEBUG", "true");
         } else {
             cmd = Command::new("cargo");
         }
@@ -285,6 +286,13 @@ fn main() {
 
     let config = LintcheckConfig::new();
 
+    if config.perf && config.max_jobs != 1 {
+        eprintln!(
+            "Lintcheck's --perf flag must be triggered only with 1 job,\nremove either the --jobs/-j flag or the --perf flag"
+        );
+        return;
+    }
+
     match config.subcommand {
         Some(Commands::Diff { old, new, truncate }) => json::diff(&old, &new, truncate),
         Some(Commands::Popular { output, number }) => popular_crates::fetch(output, number).unwrap(),