bootstrap: implement new feature bootstrap-self-test

src/bootstrap/Cargo.toml

@@ -7,6 +7,7 @@ default-run = "bootstrap"
 
 [features]
 build-metrics = ["sysinfo"]
+bootstrap-self-test = [] # enabled in the bootstrap unit tests
 
 [lib]
 path = "src/lib.rs"

src/bootstrap/src/core/build_steps/test.rs

@@ -3053,6 +3053,7 @@ impl Step for Bootstrap {
 
         let mut cmd = Command::new(&builder.initial_cargo);
         cmd.arg("test")
+            .args(["--features", "bootstrap-self-test"])
             .current_dir(builder.src.join("src/bootstrap"))
             .env("RUSTFLAGS", "-Cdebuginfo=2")
             .env("CARGO_TARGET_DIR", builder.out.join("bootstrap"))

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

@@ -22,8 +22,6 @@ use crate::utils::cache::{Interned, INTERNER};
 use crate::utils::channel::{self, GitInfo};
 use crate::utils::helpers::{exe, output, t};
 use build_helper::exit;
-use build_helper::util::fail;
-use semver::Version;
 use serde::{Deserialize, Deserializer};
 use serde_derive::Deserialize;
 
@@ -2382,8 +2380,14 @@ impl Config {
         }
     }
 
-    // check rustc/cargo version is same or lower with 1 apart from the building one
+    #[cfg(feature = "bootstrap-self-test")]
+    pub fn check_stage0_version(&self, _program_path: &Path, _component_name: &'static str) {}
+
+    /// check rustc/cargo version is same or lower with 1 apart from the building one
+    #[cfg(not(feature = "bootstrap-self-test"))]
     pub fn check_stage0_version(&self, program_path: &Path, component_name: &'static str) {
+        use build_helper::util::fail;
+
         if self.dry_run() {
             return;
         }
@@ -2400,11 +2404,12 @@ impl Config {
         }
 
         let stage0_version =
-            Version::parse(stage0_output.next().unwrap().split('-').next().unwrap().trim())
-                .unwrap();
-        let source_version =
-            Version::parse(fs::read_to_string(self.src.join("src/version")).unwrap().trim())
+            semver::Version::parse(stage0_output.next().unwrap().split('-').next().unwrap().trim())
                 .unwrap();
+        let source_version = semver::Version::parse(
+            fs::read_to_string(self.src.join("src/version")).unwrap().trim(),
+        )
+        .unwrap();
         if !(source_version == stage0_version
             || (source_version.major == stage0_version.major
                 && (source_version.minor == stage0_version.minor

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

@@ -14,16 +14,9 @@ use std::{
 };
 
 fn parse(config: &str) -> Config {
-    Config::parse_inner(
-        &[
-            "check".to_string(),
-            "--set=build.rustc=/does/not/exist".to_string(),
-            "--set=build.cargo=/does/not/exist".to_string(),
-            "--config=/does/not/exist".to_string(),
-            "--skip-stage0-validation".to_string(),
-        ],
-        |&_| toml::from_str(&config).unwrap(),
-    )
+    Config::parse_inner(&["check".to_string(), "--config=/does/not/exist".to_string()], |&_| {
+        toml::from_str(&config).unwrap()
+    })
 }
 
 #[test]
@@ -212,10 +205,7 @@ fn override_toml_duplicate() {
     Config::parse_inner(
         &[
             "check".to_owned(),
-            "--set=build.rustc=/does/not/exist".to_string(),
-            "--set=build.cargo=/does/not/exist".to_string(),
-            "--config=/does/not/exist".to_owned(),
-            "--skip-stage0-validation".to_owned(),
+            "--config=/does/not/exist".to_string(),
             "--set=change-id=1".to_owned(),
             "--set=change-id=2".to_owned(),
         ],
@@ -238,15 +228,7 @@ fn profile_user_dist() {
             .and_then(|table: toml::Value| TomlConfig::deserialize(table))
             .unwrap()
     }
-    Config::parse_inner(
-        &[
-            "check".to_owned(),
-            "--set=build.rustc=/does/not/exist".to_string(),
-            "--set=build.cargo=/does/not/exist".to_string(),
-            "--skip-stage0-validation".to_string(),
-        ],
-        get_toml,
-    );
+    Config::parse_inner(&["check".to_owned()], get_toml);
 }
 
 #[test]

src/bootstrap/src/core/download.rs

@@ -9,11 +9,10 @@ use std::{
 };
 
 use build_helper::ci::CiEnv;
-use build_helper::stage0_parser::VersionMetadata;
 use xz2::bufread::XzDecoder;
 
+use crate::utils::helpers::hex_encode;
 use crate::utils::helpers::{check_run, exe, move_file, program_out_of_date};
-use crate::{core::build_steps::llvm::detect_llvm_sha, utils::helpers::hex_encode};
 use crate::{t, Config};
 
 static SHOULD_FIX_BINS_AND_DYLIBS: OnceLock<bool> = OnceLock::new();
@@ -405,9 +404,17 @@ impl Config {
         cargo_clippy
     }
 
+    #[cfg(feature = "bootstrap-self-test")]
+    pub(crate) fn maybe_download_rustfmt(&self) -> Option<PathBuf> {
+        None
+    }
+
     /// NOTE: rustfmt is a completely different toolchain than the bootstrap compiler, so it can't
     /// reuse target directories or artifacts
+    #[cfg(not(feature = "bootstrap-self-test"))]
     pub(crate) fn maybe_download_rustfmt(&self) -> Option<PathBuf> {
+        use build_helper::stage0_parser::VersionMetadata;
+
         let VersionMetadata { date, version } = self.stage0_metadata.rustfmt.as_ref()?;
         let channel = format!("{version}-{date}");
 
@@ -487,6 +494,10 @@ impl Config {
         );
     }
 
+    #[cfg(feature = "bootstrap-self-test")]
+    pub(crate) fn download_beta_toolchain(&self) {}
+
+    #[cfg(not(feature = "bootstrap-self-test"))]
     pub(crate) fn download_beta_toolchain(&self) {
         self.verbose(|| println!("downloading stage0 beta artifacts"));
 
@@ -665,7 +676,13 @@ download-rustc = false
         self.unpack(&tarball, &bin_root, prefix);
     }
 
+    #[cfg(feature = "bootstrap-self-test")]
+    pub(crate) fn maybe_download_ci_llvm(&self) {}
+
+    #[cfg(not(feature = "bootstrap-self-test"))]
     pub(crate) fn maybe_download_ci_llvm(&self) {
+        use crate::core::build_steps::llvm::detect_llvm_sha;
+
         if !self.llvm_from_ci {
             return;
         }
@@ -707,6 +724,7 @@ download-rustc = false
         }
     }
 
+    #[cfg(not(feature = "bootstrap-self-test"))]
     fn download_ci_llvm(&self, llvm_sha: &str) {
         let llvm_assertions = self.llvm_assertions;
 

src/bootstrap/src/core/sanity.rs

@@ -8,13 +8,15 @@
 //! In theory if we get past this phase it's a bug if a build fails, but in
 //! practice that's likely not true!
 
-use std::collections::{HashMap, HashSet};
+use std::collections::HashMap;
 use std::env;
 use std::ffi::{OsStr, OsString};
 use std::fs;
 use std::path::PathBuf;
 use std::process::Command;
-use walkdir::WalkDir;
+
+#[cfg(not(feature = "bootstrap-self-test"))]
+use std::collections::HashSet;
 
 use crate::builder::Kind;
 use crate::core::config::Target;
@@ -31,6 +33,7 @@ pub struct Finder {
 // it might not yet be included in stage0. In such cases, we handle the targets missing from stage0 in this list.
 //
 // Targets can be removed from this list once they are present in the stage0 compiler (usually by updating the beta compiler of the bootstrap).
+#[cfg(not(feature = "bootstrap-self-test"))]
 const STAGE0_MISSING_TARGETS: &[&str] = &[
     // just a dummy comment so the list doesn't get onelined
 ];
@@ -167,6 +170,7 @@ than building it.
         .map(|p| cmd_finder.must_have(p))
         .or_else(|| cmd_finder.maybe_have("reuse"));
 
+    #[cfg(not(feature = "bootstrap-self-test"))]
     let stage0_supported_target_list: HashSet<String> =
         output(Command::new(&build.config.initial_rustc).args(["--print", "target-list"]))
             .lines()
@@ -193,11 +197,11 @@ than building it.
             continue;
         }
 
-        let target_str = target.to_string();
-
         // Ignore fake targets that are only used for unit tests in bootstrap.
-        if !["A-A", "B-B", "C-C"].contains(&target_str.as_str()) {
+        #[cfg(not(feature = "bootstrap-self-test"))]
+        {
             let mut has_target = false;
+            let target_str = target.to_string();
 
             let missing_targets_hashset: HashSet<_> =
                 STAGE0_MISSING_TARGETS.iter().map(|t| t.to_string()).collect();
@@ -226,7 +230,7 @@ than building it.
                     target_filename.push(".json");
 
                     // Recursively traverse through nested directories.
-                    let walker = WalkDir::new(custom_target_path).into_iter();
+                    let walker = walkdir::WalkDir::new(custom_target_path).into_iter();
                     for entry in walker.filter_map(|e| e.ok()) {
                         has_target |= entry.file_name() == target_filename;
                     }