Add PROC_MACRO_TEST_TOOLCHAIN environment variable
This allows overriding the toolchain used to run `proc-macro-srv` tests.
---
Sample usage.
Testing the current ABI (variable unset/empty):
```shell
amos@tails ~/bearcove/rust-analyzer/crates/proc-macro-srv proc-macro-test-toolchain*
❯ PROC_MACRO_TEST_TOOLCHAIN="" cargo test --quiet
running 16 tests
................
test result: ok. 16 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.01s
```
Testing an older ABI:
```shell
amos@tails ~/bearcove/rust-analyzer/crates/proc-macro-srv proc-macro-test-toolchain*
❯ PROC_MACRO_TEST_TOOLCHAIN="1.58" cargo test --quiet
running 16 tests
................
test result: ok. 16 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.01s
```
Testing current nightly ABI:
```shell
❯ rustc +nightly --version
rustc 1.64.0-nightly (
f8588549c 2022-07-18)
❯ PROC_MACRO_TEST_TOOLCHAIN="nightly" cargo test --quiet
running 16 tests
................
test result: ok. 16 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.01s
```
Testing future ABI (`rust-lang/rust` master):
```shell
amos@tails ~/bearcove/rust-analyzer/crates/proc-macro-srv proc-macro-test-toolchain
❯ PROC_MACRO_TEST_TOOLCHAIN="stage1" cargo test --quiet
running 16 tests
..........thread '<unnamed>' panicked at 'range end index
216221164920373249 out of range for slice of length 18', library/core/src/slice/index.rs:73:5
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
....F.
failures:
---- tests::test_fn_like_macro2 stdout ----
thread 'tests::test_fn_like_macro2' panicked at 'called `Result::unwrap()` on an `Err` value: "range end index
216221164920373249 out of range for slice of length 18"', crates/proc-macro-srv/src/tests/utils.rs:38:83
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
failures:
tests::test_fn_like_macro2
test result: FAILED. 15 passed; 1 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s
error: test failed, to rerun pass '--lib
```
---
Tagging `@jonas-schievink:` this might be helpful when updating versioned ABIs later on.
//! `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,
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);
}
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