Merge #9192

9192: internal: Build test-macros in a build script r=jonas-schievink a=jonas-schievink

This build the test-proc-macros in `proc_macro_test` in a build script, and copies the artifact to `OUT_DIR`. This should make it available throughout all of rust-analyzer at no cost other than depending on `proc_macro_test`, fixing https://github.com/rust-analyzer/rust-analyzer/issues/9067.

This hopefully will let us later write inline tests that utilize proc macros, which makes my life fixing proc macro bugs easier.

Opening this as a sort of RFC, because I'm not totally sure this approach is the best.

Co-authored-by: Jonas Schievink <[email protected]>

6 files changed, 122 insertions, 47 deletions

diff --git a/crates/proc_macro_test/Cargo.toml b/crates/proc_macro_test/Cargo.toml
index 753443be2..1a88e361e 100644
--- a/crates/proc_macro_test/Cargo.toml
+++ b/crates/proc_macro_test/Cargo.toml
@@ -8,4 +8,8 @@ publish = false
 
 [lib]
 doctest = false
-proc-macro = true
+
+[build-dependencies]
+proc_macro_test_impl = { path = "imp", version = "0.0.0" }
+toolchain = { path = "../toolchain", version = "0.0.0" }
+cargo_metadata = "0.13"
diff --git a/crates/proc_macro_test/build.rs b/crates/proc_macro_test/build.rs
new file mode 100644
index 000000000..4653a93dd
--- /dev/null
+++ b/crates/proc_macro_test/build.rs
@@ -0,0 +1,48 @@
+//! This will build the proc macro in `imp`, and copy the resulting dylib artifact into the
+//! `OUT_DIR`.
+//!
+//! `proc_macro_test` itself contains only a path to that artifact.
+
+use std::{
+    env, fs,
+    path::{Path, PathBuf},
+    process::Command,
+};
+
+use cargo_metadata::Message;
+
+fn main() {
+    let out_dir = env::var_os("OUT_DIR").unwrap();
+    let out_dir = Path::new(&out_dir);
+
+    let name = "proc_macro_test_impl";
+    let version = "0.0.0";
+    let output = Command::new(toolchain::cargo())
+        .current_dir("imp")
+        .args(&["build", "-p", "proc_macro_test_impl", "--message-format", "json"])
+        .output()
+        .unwrap();
+    assert!(output.status.success());
+
+    let mut artifact_path = None;
+    for message in Message::parse_stream(output.stdout.as_slice()) {
+        match message.unwrap() {
+            Message::CompilerArtifact(artifact) => {
+                if artifact.target.kind.contains(&"proc-macro".to_string()) {
+                    let repr = format!("{} {}", name, version);
+                    if artifact.package_id.repr.starts_with(&repr) {
+                        artifact_path = Some(PathBuf::from(&artifact.filenames[0]));
+                    }
+                }
+            }
+            _ => (), // Unknown message
+        }
+    }
+
+    let src_path = artifact_path.expect("no dylib for proc_macro_test_impl found");
+    let dest_path = out_dir.join(src_path.file_name().unwrap());
+    fs::copy(src_path, &dest_path).unwrap();
+
+    let info_path = out_dir.join("proc_macro_test_location.txt");
+    fs::write(info_path, dest_path.to_str().unwrap()).unwrap();
+}
diff --git a/crates/proc_macro_test/imp/.gitignore b/crates/proc_macro_test/imp/.gitignore
new file mode 100644
index 000000000..2c96eb1b6
--- /dev/null
+++ b/crates/proc_macro_test/imp/.gitignore
@@ -0,0 +1,2 @@
+target/
+Cargo.lock
diff --git a/crates/proc_macro_test/imp/Cargo.toml b/crates/proc_macro_test/imp/Cargo.toml
new file mode 100644
index 000000000..1c2e75401
--- /dev/null
+++ b/crates/proc_macro_test/imp/Cargo.toml
@@ -0,0 +1,17 @@
+[package]
+name = "proc_macro_test_impl"
+version = "0.0.0"
+license = "MIT OR Apache-2.0"
+authors = ["rust-analyzer developers"]
+edition = "2018"
+publish = false
+
+[lib]
+doctest = false
+proc-macro = true
+
+[workspace]
+
+[dependencies]
+# this crate should not have any dependencies, since it uses its own workspace,
+# and its own `Cargo.lock`
diff --git a/crates/proc_macro_test/imp/src/lib.rs b/crates/proc_macro_test/imp/src/lib.rs
new file mode 100644
index 000000000..4b26d2472
--- /dev/null
+++ b/crates/proc_macro_test/imp/src/lib.rs
@@ -0,0 +1,48 @@
+//! Exports a few trivial procedural macros for testing.
+
+use proc_macro::TokenStream;
+
+#[proc_macro]
+pub fn fn_like_noop(args: TokenStream) -> TokenStream {
+    args
+}
+
+#[proc_macro]
+pub fn fn_like_panic(args: TokenStream) -> TokenStream {
+    panic!("fn_like_panic!({})", args);
+}
+
+#[proc_macro]
+pub fn fn_like_error(args: TokenStream) -> TokenStream {
+    format!("compile_error!(\"fn_like_error!({})\");", args).parse().unwrap()
+}
+
+#[proc_macro_attribute]
+pub fn attr_noop(_args: TokenStream, item: TokenStream) -> TokenStream {
+    item
+}
+
+#[proc_macro_attribute]
+pub fn attr_panic(args: TokenStream, item: TokenStream) -> TokenStream {
+    panic!("#[attr_panic {}] {}", args, item);
+}
+
+#[proc_macro_attribute]
+pub fn attr_error(args: TokenStream, item: TokenStream) -> TokenStream {
+    format!("compile_error!(\"#[attr_error({})] {}\");", args, item).parse().unwrap()
+}
+
+#[proc_macro_derive(DeriveEmpty)]
+pub fn derive_empty(_item: TokenStream) -> TokenStream {
+    TokenStream::new()
+}
+
+#[proc_macro_derive(DerivePanic)]
+pub fn derive_panic(item: TokenStream) -> TokenStream {
+    panic!("#[derive(DerivePanic)] {}", item);
+}
+
+#[proc_macro_derive(DeriveError)]
+pub fn derive_error(item: TokenStream) -> TokenStream {
+    format!("compile_error!(\"#[derive(DeriveError)] {}\");", item).parse().unwrap()
+}
diff --git a/crates/proc_macro_test/src/lib.rs b/crates/proc_macro_test/src/lib.rs
index 4b26d2472..2edf23a63 100644
--- a/crates/proc_macro_test/src/lib.rs
+++ b/crates/proc_macro_test/src/lib.rs
@@ -1,48 +1,4 @@
 //! Exports a few trivial procedural macros for testing.
 
-use proc_macro::TokenStream;
-
-#[proc_macro]
-pub fn fn_like_noop(args: TokenStream) -> TokenStream {
-    args
-}
-
-#[proc_macro]
-pub fn fn_like_panic(args: TokenStream) -> TokenStream {
-    panic!("fn_like_panic!({})", args);
-}
-
-#[proc_macro]
-pub fn fn_like_error(args: TokenStream) -> TokenStream {
-    format!("compile_error!(\"fn_like_error!({})\");", args).parse().unwrap()
-}
-
-#[proc_macro_attribute]
-pub fn attr_noop(_args: TokenStream, item: TokenStream) -> TokenStream {
-    item
-}
-
-#[proc_macro_attribute]
-pub fn attr_panic(args: TokenStream, item: TokenStream) -> TokenStream {
-    panic!("#[attr_panic {}] {}", args, item);
-}
-
-#[proc_macro_attribute]
-pub fn attr_error(args: TokenStream, item: TokenStream) -> TokenStream {
-    format!("compile_error!(\"#[attr_error({})] {}\");", args, item).parse().unwrap()
-}
-
-#[proc_macro_derive(DeriveEmpty)]
-pub fn derive_empty(_item: TokenStream) -> TokenStream {
-    TokenStream::new()
-}
-
-#[proc_macro_derive(DerivePanic)]
-pub fn derive_panic(item: TokenStream) -> TokenStream {
-    panic!("#[derive(DerivePanic)] {}", item);
-}
-
-#[proc_macro_derive(DeriveError)]
-pub fn derive_error(item: TokenStream) -> TokenStream {
-    format!("compile_error!(\"#[derive(DeriveError)] {}\");", item).parse().unwrap()
-}
+pub static PROC_MACRO_TEST_LOCATION: &str =
+    include_str!(concat!(env!("OUT_DIR"), "/proc_macro_test_location.txt"));