Auto merge of #146595 - Shourya742:make-cargo-test-work-for-self-test, r=Kobzol

Make cargo test work for  bootstrap self test

This PR enables the bootstrap self-test to run via cargo test. I have removed the detect_src_and_out test for now, but it will be reintroduced in a follow-up PR where all bootstrap tests will be migrated to use testCtx.

r? `@Kobzol`

Author: bors

src/bootstrap/src/core/builder/tests.rs

@@ -22,13 +22,7 @@ fn configure(cmd: &str, host: &[&str], target: &[&str]) -> Config {
 }
 
 fn configure_with_args(cmd: &[&str], host: &[&str], target: &[&str]) -> Config {
-    TestCtx::new()
-        .config(cmd[0])
-        .args(&cmd[1..])
-        .hosts(host)
-        .targets(target)
-        .args(&["--build", TEST_TRIPLE_1])
-        .create_config()
+    TestCtx::new().config(cmd[0]).args(&cmd[1..]).hosts(host).targets(target).create_config()
 }
 
 fn first<A, B>(v: Vec<(A, B)>) -> Vec<A> {
@@ -218,25 +212,25 @@ fn prepare_rustc_checkout(ctx: &mut GitCtx) {
 
 /// Parses a Config directory from `path`, with the given value of `download_rustc`.
 fn parse_config_download_rustc_at(path: &Path, download_rustc: &str, ci: bool) -> Config {
-    Config::parse_inner(
-        Flags::parse(&[
-            "build".to_owned(),
-            "--dry-run".to_owned(),
-            "--ci".to_owned(),
-            if ci { "true" } else { "false" }.to_owned(),
-            format!("--set=rust.download-rustc='{download_rustc}'"),
-            "--src".to_owned(),
-            path.to_str().unwrap().to_owned(),
-        ]),
-        |&_| Ok(Default::default()),
-    )
+    TestCtx::new()
+        .config("build")
+        .args(&[
+            "--ci",
+            if ci { "true" } else { "false" },
+            format!("--set=rust.download-rustc='{download_rustc}'").as_str(),
+            "--src",
+            path.to_str().unwrap(),
+        ])
+        .no_override_download_ci_llvm()
+        .create_config()
 }
 
 mod dist {
     use pretty_assertions::assert_eq;
 
     use super::{Config, TEST_TRIPLE_1, TEST_TRIPLE_2, TEST_TRIPLE_3, first, run_build};
     use crate::Flags;
+    use crate::core::builder::tests::host_target;
     use crate::core::builder::*;
 
     fn configure(host: &[&str], target: &[&str]) -> Config {
@@ -245,11 +239,11 @@ mod dist {
 
     #[test]
     fn llvm_out_behaviour() {
-        let mut config = configure(&[TEST_TRIPLE_1], &[TEST_TRIPLE_2]);
+        let mut config = configure(&[], &[TEST_TRIPLE_2]);
         config.llvm_from_ci = true;
         let build = Build::new(config.clone());
 
-        let target = TargetSelection::from_user(TEST_TRIPLE_1);
+        let target = TargetSelection::from_user(&host_target());
         assert!(build.llvm_out(target).ends_with("ci-llvm"));
         let target = TargetSelection::from_user(TEST_TRIPLE_2);
         assert!(build.llvm_out(target).ends_with("llvm"));
@@ -314,7 +308,7 @@ mod sysroot_target_dirs {
 /// cg_gcc tests instead.
 #[test]
 fn test_test_compiler() {
-    let config = configure_with_args(&["test", "compiler"], &[TEST_TRIPLE_1], &[TEST_TRIPLE_1]);
+    let config = configure_with_args(&["test", "compiler"], &[&host_target()], &[TEST_TRIPLE_1]);
     let cache = run_build(&config.paths.clone(), config);
 
     let compiler = cache.contains::<test::CrateLibrustc>();
@@ -347,7 +341,7 @@ fn test_test_coverage() {
         // Print each test case so that if one fails, the most recently printed
         // case is the one that failed.
         println!("Testing case: {cmd:?}");
-        let config = configure_with_args(cmd, &[TEST_TRIPLE_1], &[TEST_TRIPLE_1]);
+        let config = configure_with_args(cmd, &[], &[TEST_TRIPLE_1]);
         let mut cache = run_build(&config.paths.clone(), config);
 
         let modes =
@@ -359,14 +353,7 @@ fn test_test_coverage() {
 #[test]
 fn test_prebuilt_llvm_config_path_resolution() {
     fn configure(config: &str) -> Config {
-        Config::parse_inner(
-            Flags::parse(&[
-                "build".to_string(),
-                "--dry-run".to_string(),
-                "--config=/does/not/exist".to_string(),
-            ]),
-            |&_| toml::from_str(&config),
-        )
+        TestCtx::new().config("build").with_default_toml_config(config).create_config()
     }
 
     // Removes Windows disk prefix if present

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

@@ -424,6 +424,18 @@ impl Config {
             src = src_;
         }
 
+        #[cfg(test)]
+        {
+            if let Some(config_path) = flags_config.as_ref() {
+                assert!(
+                    !config_path.starts_with(&src),
+                    "Path {config_path:?} should not be inside or equal to src dir {src:?}"
+                );
+            } else {
+                panic!("During test the config should be explicitly added");
+            }
+        }
+
         // Now load the TOML config, as soon as possible
         let (mut toml, toml_path) = load_toml_config(&src, flags_config, &get_toml);
 
@@ -630,19 +642,13 @@ impl Config {
         let llvm_assertions = llvm_assertions.unwrap_or(false);
         let mut target_config = HashMap::new();
         let mut channel = "dev".to_string();
-        let out = flags_build_dir.or(build_build_dir.map(PathBuf::from)).unwrap_or_else(|| {
-            if cfg!(test) {
-                // Use the build directory of the original x.py invocation, so that we can set `initial_rustc` properly.
-                Path::new(
-                    &env::var_os("CARGO_TARGET_DIR").expect("cargo test directly is not supported"),
-                )
-                .parent()
-                .unwrap()
-                .to_path_buf()
-            } else {
-                PathBuf::from("build")
-            }
-        });
+        let out = if cfg!(test) {
+            test_build_dir()
+        } else {
+            flags_build_dir
+                .or_else(|| build_build_dir.map(PathBuf::from))
+                .unwrap_or_else(|| PathBuf::from("build"))
+        };
 
         // NOTE: Bootstrap spawns various commands with different working directories.
         // To avoid writing to random places on the file system, `config.out` needs to be an absolute path.
@@ -2484,3 +2490,22 @@ fn find_correct_section_for_field(field_name: &str) -> Vec<WouldBeValidFor> {
         })
         .collect()
 }
+
+/// Resolve the build directory used for tests.
+///
+/// - When tests are run through bootstrap (`x.py test`), the build system
+///   sets `CARGO_TARGET_DIR`, so we can trust and use it here.
+/// - When tests are run directly with cargo test, `CARGO_TARGET_DIR` will
+///   not be set. In that case we fall back to resolving relative to
+///   `CARGO_MANIFEST_DIR`, by walking two parents up and appending `build`.
+fn test_build_dir() -> PathBuf {
+    env::var_os("CARGO_TARGET_DIR")
+        .map(|value| Path::new(&value).parent().unwrap().to_path_buf())
+        .unwrap_or_else(|| {
+            let base = option_env!("CARGO_MANIFEST_DIR")
+                .map(PathBuf::from)
+                .unwrap_or_else(|| std::env::current_dir().expect("failed to get current dir"));
+
+            base.ancestors().nth(2).unwrap_or_else(|| Path::new(".")).join("build")
+        })
+}