Make cargo test work again

src/bootstrap/src/core/config/config.rs

@@ -414,15 +414,17 @@ impl Config {
  // Set config values based on flags.
  let mut exec_ctx = ExecutionContext::new(flags_verbose, flags_cmd.fail_fast());
  exec_ctx.set_dry_run(if flags_dry_run { DryRun::UserSelected } else { DryRun::Disabled });
- let mut src = {
+
+ let default_src_dir = {
  let manifest_dir = PathBuf::from(env!("CARGO_MANIFEST_DIR"));
  // Undo `src/bootstrap`
  manifest_dir.parent().unwrap().parent().unwrap().to_owned()
  };
-
- if let Some(src_) = compute_src_directory(flags_src, &exec_ctx) {
- src = src_;
- }
+ let src = if let Some(s) = compute_src_directory(flags_src, &exec_ctx) {
+ s
+ } else {
+ default_src_dir.clone()
+ };
 
  #[cfg(test)]
  {
@@ -659,6 +661,10 @@ impl Config {
  out
  };
 
+ let default_stage0_rustc_path = |dir: &Path| {
+ dir.join(host_target).join("stage0").join("bin").join(exe("rustc", host_target))
+ };
+
  if cfg!(test) {
  // When configuring bootstrap for tests, make sure to set the rustc and Cargo to the
  // same ones used to call the tests (if custom ones are not defined in the toml). If we
@@ -667,6 +673,22 @@ impl Config {
  // Cargo in their bootstrap.toml.
  build_rustc = build_rustc.take().or(std::env::var_os("RUSTC").map(|p| p.into()));
  build_cargo = build_cargo.take().or(std::env::var_os("CARGO").map(|p| p.into()));
+
+ // If we are running only `cargo test` (and not `x test bootstrap`), which is useful
+ // e.g. for debugging bootstrap itself, then we won't have RUSTC and CARGO set to the
+ // proper paths.
+ // We thus "guess" that the build directory is located at <src>/build, and try to load
+ // rustc and cargo from there
+ let is_test_outside_x = std::env::var("CARGO_TARGET_DIR").is_err();
+ if is_test_outside_x && build_rustc.is_none() {
+ let stage0_rustc = default_stage0_rustc_path(&default_src_dir.join("build"));
+ assert!(
+ stage0_rustc.exists(),
+ "Trying to run cargo test without having a stage0 rustc available in {}",
+ stage0_rustc.display()
+ );
+ build_rustc = Some(stage0_rustc);
+ }
  }
 
  if !flags_skip_stage0_validation {
@@ -700,7 +722,7 @@ impl Config {
 
  let initial_rustc = build_rustc.unwrap_or_else(|| {
  download_beta_toolchain(&dwn_ctx, &out);
- out.join(host_target).join("stage0").join("bin").join(exe("rustc", host_target))
+ default_stage0_rustc_path(&out)
  });
 
  let initial_sysroot = t!(PathBuf::from_str(
@@ -1540,11 +1562,11 @@ impl Config {
  println!("WARNING: CI rustc has some fields that are no longer supported in bootstrap; download-rustc will be disabled.");
  println!("HELP: Consider rebasing to a newer commit if available.");
  return None;
- },
+ }
  Err(e) => {
  eprintln!("ERROR: Failed to parse CI rustc bootstrap.toml: {e}");
  exit!(2);
- },
+ }
  };
 
  let current_config_toml = Self::get_toml(config_path).unwrap();