From 921618c7fc600b10d452bf637f467ed6c3088459 Mon Sep 17 00:00:00 2001
From: Eric Huss <eric@huss.org>
Date: Sat, 11 Feb 2023 15:07:51 -0800
Subject: [PATCH] Add RUSTUP_TOOLCHAIN_DIR

---
 src/toolchain.rs           |  1 +
 tests/cli-rustup.rs        | 18 +++++++++++++++++-
 tests/mock/mock_bin_src.rs |  5 +++++
 3 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/src/toolchain.rs b/src/toolchain.rs
index c91b9777ca..0e1300f90f 100644
--- a/src/toolchain.rs
+++ b/src/toolchain.rs
@@ -401,6 +401,7 @@ impl<'a> InstalledCommonToolchain<'a> {
 
         cmd.env("RUSTUP_TOOLCHAIN", &self.0.name);
         cmd.env("RUSTUP_HOME", &self.0.cfg.rustup_dir);
+        cmd.env("RUSTUP_TOOLCHAIN_DIR", &self.0.path);
     }
 
     fn set_ldpath(&self, cmd: &mut Command) {
diff --git a/tests/cli-rustup.rs b/tests/cli-rustup.rs
index ea8a9c32fa..2f8bdb3eb3 100644
--- a/tests/cli-rustup.rs
+++ b/tests/cli-rustup.rs
@@ -4,7 +4,7 @@ pub mod mock;
 
 use std::env::consts::EXE_SUFFIX;
 use std::fs;
-use std::path::{PathBuf, MAIN_SEPARATOR};
+use std::path::{Path, PathBuf, MAIN_SEPARATOR};
 
 use rustup::for_host;
 use rustup::test::this_host_triple;
@@ -2252,3 +2252,19 @@ fn warn_on_duplicate_rust_toolchain_file() {
         );
     });
 }
+
+/// Checks that the RUSTUP_TOOLCHAIN_DIR is set.
+#[test]
+fn toolchain_dir_env() {
+    setup(&|config| {
+        expect_ok(config, &["rustup", "default", "nightly"]);
+        let output = clitools::run(config, "rustup", &["which", "rustc"], &[]);
+        let real_mock_rustc = Path::new(output.stdout.trim());
+        let toolchain_dir = real_mock_rustc.parent().unwrap().parent().unwrap();
+        expect_stderr_ok(
+            config,
+            &["rustc", "--echo-env", "RUSTUP_TOOLCHAIN_DIR"],
+            toolchain_dir.to_str().unwrap(),
+        );
+    });
+}
diff --git a/tests/mock/mock_bin_src.rs b/tests/mock/mock_bin_src.rs
index 7acafb67e1..e8e10cbae7 100644
--- a/tests/mock/mock_bin_src.rs
+++ b/tests/mock/mock_bin_src.rs
@@ -71,6 +71,11 @@ fn main() {
             let mut out = io::stderr();
             writeln!(out, "{}", std::env::var("PATH").unwrap()).unwrap();
         }
+        Some("--echo-env") => {
+            let mut out = io::stderr();
+            let var = args.next().unwrap();
+            writeln!(out, "{}", std::env::var(var).unwrap_or_default()).unwrap();
+        }
         _ => panic!("bad mock proxy commandline"),
     }
 }