Update different type used for Sysroot in crubit

Used to be PathBuf in rustc, now new Sysroot struct.

PiperOrigin-RevId: 778440356
Change-Id: I1be2c5e00a43c35454716c1a16948d3dca3a9df0

Author: hzeller

cargo/cc_bindings_from_rs/run_compiler/Cargo.toml

@@ -18,3 +18,4 @@ path = "../../../cc_bindings_from_rs/run_compiler.rs"
 [dependencies]
 arc_anyhow = { path = "../../../cargo/common/arc_anyhow"}
 either.workspace = true
+rustversion.workspace = true

cc_bindings_from_rs/BUILD

@@ -134,6 +134,9 @@ rust_library(
     srcs = [
         "run_compiler.rs",
     ],
+    proc_macro_deps = [
+        "@crate_index//:rustversion",
+    ],
     # LINT.IfChange
     rustc_flags = ["-Zallow-features=rustc_private,cfg_accessible"],
     # LINT.ThenChange(//docs/overview/unstable_features.md)

cc_bindings_from_rs/run_compiler.rs

@@ -21,6 +21,7 @@ use rustc_interface::interface::Compiler;
 use rustc_middle::ty::TyCtxt; // See also <internal link>/ty.html#import-conventions
 use rustc_session::config::ErrorOutputType;
 use rustc_session::EarlyDiagCtxt;
+use std::path::PathBuf;
 
 /// Wrapper around `rustc_driver::RunCompiler::run` that exposes a
 /// simplified API:
@@ -202,6 +203,16 @@ mod tests {
         Ok(())
     }
 
+    #[rustversion::before(2025-06-25)]
+    fn sysroot_path() -> PathBuf {
+        get_sysroot_for_testing()
+    }
+
+    #[rustversion::since(2025-06-25)]
+    fn sysroot_path() -> PathBuf {
+        get_sysroot_for_testing().path().to_path_buf()
+    }
+
     /// `test_run_compiler_no_output_file` tests that we stop the compilation
     /// midway (i.e. that we return `Stop` from `after_analysis`).
     #[test]
@@ -216,7 +227,7 @@ mod tests {
             // Default parameters.
             "run_compiler_unittest_executable".to_string(),
             "--crate-type=lib".to_string(),
-            format!("--sysroot={}", get_sysroot_for_testing().display()),
+            format!("--sysroot={}", sysroot_path().display()),
             rs_path.display().to_string(),
             // Test-specific parameter: asking for after-analysis output
             "-o".to_string(),

cc_bindings_from_rs/run_compiler_test_support.rs

@@ -19,10 +19,17 @@ use itertools::Itertools;
 
 use rustc_middle::ty::TyCtxt;
 use rustc_session::config::{CrateType, Input, Options, OutputType, OutputTypes};
+
+#[rustversion::since(2025-06-25)]
+use rustc_session::config::Sysroot;
+
 use rustc_span::def_id::LocalDefId;
 use rustc_target::spec::TargetTuple;
 
-use std::path::{Path, PathBuf};
+use std::path::Path;
+
+#[rustversion::before(2025-06-25)]
+use std::path::PathBuf;
 
 #[cfg(oss)]
 const TOOLCHAIN_ROOT: &str = "rust_linux_x86_64__x86_64-unknown-linux-gnu__nightly_tools/rust_toolchain/lib/rustlib/x86_64-unknown-linux-gnu";
@@ -35,6 +42,8 @@ const TOOLCHAIN_ROOT: &str = env!("G3_SYSROOT_PATH");
 /// The sysroot is used internally by `run_compiler_for_testing`, but it may
 /// also be passed as `--sysroot=...` in `rustc_args` argument of
 /// `run_compiler`
+
+#[rustversion::before(2025-06-25)]
 pub fn get_sysroot_for_testing() -> PathBuf {
     let runfiles = runfiles::Runfiles::create().unwrap();
     let loc = runfiles.rlocation(Path::new(TOOLCHAIN_ROOT)).expect("Failed to locate runfile");
@@ -43,6 +52,15 @@ pub fn get_sysroot_for_testing() -> PathBuf {
     loc
 }
 
+#[rustversion::since(2025-06-25)]
+pub fn get_sysroot_for_testing() -> Sysroot {
+    let runfiles = runfiles::Runfiles::create().unwrap();
+    let loc = runfiles.rlocation(Path::new(TOOLCHAIN_ROOT)).expect("Failed to locate runfile");
+    assert!(loc.exists(), "Sysroot directory '{}' doesn't exist", loc.display());
+    assert!(loc.is_dir(), "Provided sysroot '{}' is not a directory", loc.display());
+    Sysroot::new(Some(loc))
+}
+
 /// If a rustc --target arg is necessary, sets it up and returns its value.
 ///
 /// We use a target json in some configurations. Its filename needs to match the