Add PROC_MACRO_TEST_TOOLCHAIN environment variable
This allows overriding the toolchain used to run `proc-macro-srv` tests.
//! `OUT_DIR`.
//!
//! `proc-macro-test` itself contains only a path to that artifact.
+//!
+//! The `PROC_MACRO_TEST_TOOLCHAIN` environment variable can be exported to use
+//! a specific rustup toolchain: this allows testing against older ABIs (e.g.
+//! 1.58) and future ABIs (stage1, nightly)
use std::{
env, fs,
@@ -13,6 +17,7 @@ use cargo_metadata::Message;
fn main() {
println!("cargo:rerun-if-changed=imp");
+ println!("cargo:rerun-if-env-changed=PROC_MACRO_TEST_TOOLCHAIN");
let out_dir = env::var_os("OUT_DIR").unwrap();
let out_dir = Path::new(&out_dir);
@@ -47,7 +52,17 @@ fn main() {
}
let target_dir = out_dir.join("target");
- let output = Command::new(toolchain::cargo())
+
+ let mut cmd = if let Ok(toolchain) = std::env::var("PROC_MACRO_TEST_TOOLCHAIN") {
+ // leverage rustup to find user-specific toolchain
+ let mut cmd = Command::new("cargo");
+ cmd.arg(format!("+{toolchain}"));
+ cmd
+ } else {
+ Command::new(toolchain::cargo())
+ };
+
+ let output = cmd
.current_dir(&staging_dir)
.args(&["build", "-p", "proc-macro-test-impl", "--message-format", "json"])
// Explicit override the target directory to avoid using the same one which the parent
