make runtime macros more IDE friendly (#391)

Author: robjtede

actix-macros/CHANGES.md

@@ -1,6 +1,10 @@
 # Changes
 
 ## Unreleased - 2021-xx-xx
+* Improve error recovery potential when macro input is invalid. [#391]
+* Allow custom `System`s on test macro. [#391]
+
+[#391]: https://github.com/actix/actix-net/pull/391
 
 
 ## 0.2.1 - 2021-02-02

actix-macros/src/lib.rs

@@ -28,7 +28,12 @@ use quote::quote;
 #[proc_macro_attribute]
 #[cfg(not(test))] // Work around for rust-lang/rust#62127
 pub fn main(args: TokenStream, item: TokenStream) -> TokenStream {
-    let mut input = syn::parse_macro_input!(item as syn::ItemFn);
+    let mut input = match syn::parse::<syn::ItemFn>(item.clone()) {
+        Ok(input) => input,
+        // on parse err, make IDEs happy; see fn docs
+        Err(err) => return input_and_compile_error(item, err),
+    };
+
     let args = syn::parse_macro_input!(args as syn::AttributeArgs);
 
     let attrs = &input.attrs;
@@ -101,8 +106,15 @@ pub fn main(args: TokenStream, item: TokenStream) -> TokenStream {
 /// }
 /// ```
 #[proc_macro_attribute]
-pub fn test(_: TokenStream, item: TokenStream) -> TokenStream {
-    let mut input = syn::parse_macro_input!(item as syn::ItemFn);
+pub fn test(args: TokenStream, item: TokenStream) -> TokenStream {
+    let mut input = match syn::parse::<syn::ItemFn>(item.clone()) {
+        Ok(input) => input,
+        // on parse err, make IDEs happy; see fn docs
+        Err(err) => return input_and_compile_error(item, err),
+    };
+
+    let args = syn::parse_macro_input!(args as syn::AttributeArgs);
+
     let attrs = &input.attrs;
     let vis = &input.vis;
     let sig = &mut input.sig;
@@ -132,13 +144,59 @@ pub fn test(_: TokenStream, item: TokenStream) -> TokenStream {
         quote!(#[test])
     };
 
+    let mut system = syn::parse_str::<syn::Path>("::actix_rt::System").unwrap();
+
+    for arg in &args {
+        match arg {
+            syn::NestedMeta::Meta(syn::Meta::NameValue(syn::MetaNameValue {
+                lit: syn::Lit::Str(lit),
+                path,
+                ..
+            })) => match path
+                .get_ident()
+                .map(|i| i.to_string().to_lowercase())
+                .as_deref()
+            {
+                Some("system") => match lit.parse() {
+                    Ok(path) => system = path,
+                    Err(_) => {
+                        return syn::Error::new_spanned(lit, "Expected path")
+                            .to_compile_error()
+                            .into();
+                    }
+                },
+                _ => {
+                    return syn::Error::new_spanned(arg, "Unknown attribute specified")
+                        .to_compile_error()
+                        .into();
+                }
+            },
+            _ => {
+                return syn::Error::new_spanned(arg, "Unknown attribute specified")
+                    .to_compile_error()
+                    .into();
+            }
+        }
+    }
+
     (quote! {
         #missing_test_attr
         #(#attrs)*
         #vis #sig {
-            actix_rt::System::new()
-                .block_on(async { #body })
+            <#system>::new().block_on(async { #body })
         }
     })
     .into()
 }
+
+/// Converts the error to a token stream and appends it to the original input.
+///
+/// Returning the original input in addition to the error is good for IDEs which can gracefully
+/// recover and show more precise errors within the macro body.
+///
+/// See <https://github.com/rust-analyzer/rust-analyzer/issues/10468> for more info.
+fn input_and_compile_error(mut item: TokenStream, err: syn::Error) -> TokenStream {
+    let compile_err = TokenStream::from(err.to_compile_error());
+    item.extend(compile_err);
+    return item;
+}

actix-macros/tests/trybuild.rs

@@ -11,4 +11,7 @@ fn compile_macros() {
     t.pass("tests/trybuild/test-01-basic.rs");
     t.pass("tests/trybuild/test-02-keep-attrs.rs");
     t.compile_fail("tests/trybuild/test-03-only-async.rs");
+    t.pass("tests/trybuild/test-04-system-path.rs");
+    t.compile_fail("tests/trybuild/test-05-system-expect-path.rs");
+    t.compile_fail("tests/trybuild/test-06-unknown-attr.rs");
 }

actix-macros/tests/trybuild/test-04-system-path.rs

@@ -0,0 +1,10 @@
+mod system {
+    pub use actix_rt::System as MySystem;
+}
+
+#[actix_rt::test(system = "system::MySystem")]
+async fn my_test() {
+    futures_util::future::ready(()).await
+}
+
+fn main() {}

actix-macros/tests/trybuild/test-05-system-expect-path.rs

@@ -0,0 +1,4 @@
+#[actix_rt::test(system = "!@#*&")]
+async fn my_test() {}
+
+fn main() {}

actix-macros/tests/trybuild/test-05-system-expect-path.stderr

@@ -0,0 +1,5 @@
+error: Expected path
+ --> $DIR/test-05-system-expect-path.rs:1:27
+  |
+1 | #[actix_rt::test(system = "!@#*&")]
+  |                           ^^^^^^^

actix-macros/tests/trybuild/test-06-unknown-attr.rs

@@ -0,0 +1,7 @@
+#[actix_rt::test(foo = "bar")]
+async fn my_test_1() {}
+
+#[actix_rt::test(bar::baz)]
+async fn my_test_2() {}
+
+fn main() {}

actix-macros/tests/trybuild/test-06-unknown-attr.stderr

@@ -0,0 +1,11 @@
+error: Unknown attribute specified
+ --> $DIR/test-06-unknown-attr.rs:1:18
+  |
+1 | #[actix_rt::test(foo = "bar")]
+  |                  ^^^^^^^^^^^
+
+error: Unknown attribute specified
+ --> $DIR/test-06-unknown-attr.rs:4:18
+  |
+4 | #[actix_rt::test(bar::baz)]
+  |                  ^^^^^^^^

bytestring/Cargo.toml

@@ -24,4 +24,5 @@ serde = { version = "1.0", optional = true }
 
 [dev-dependencies]
 serde_json = "1.0"
-ahash = { version = "0.7", default-features = false }
+# TODO: remove when ahash MSRV is restored
+ahash = { version = "=0.7.4", default-features = false }