add freeze_struct_ignore_ra

Author: sam0x17

support/macros/build.rs

@@ -0,0 +1,9 @@
+use std::env;
+
+fn main() {
+    // Read the RUSTC_WRAPPER environment variable
+    if let Ok(rustc_wrapper) = env::var("RUSTC_WRAPPER") {
+        // Pass the RUSTC_WRAPPER to rust build
+        println!("cargo:rustc-env=RUSTC_WRAPPER={}", rustc_wrapper);
+    }
+}

support/macros/src/lib.rs

@@ -6,9 +6,24 @@ use syn::{parse2, visit_mut::visit_item_struct_mut, Error, ItemStruct, LitStr, R
 mod visitor;
 use visitor::*;
 
+/// Freezes the layout of a struct to the current hash of its fields, ensuring that future
+/// changes require updating the hash.
+///
+/// If you ever get in a loop where rust analyzer insists that the hash is wrong each time you
+/// update, but `cargo check` is passing, you should use [`freeze_struct_ignore_ra`] instead.
 #[proc_macro_attribute]
 pub fn freeze_struct(attr: TokenStream, tokens: TokenStream) -> TokenStream {
-    match freeze_struct_impl(attr, tokens) {
+    match freeze_struct_impl(attr, tokens, false) {
+        Ok(item_struct) => item_struct.to_token_stream().into(),
+        Err(err) => err.to_compile_error().into(),
+    }
+}
+
+/// More permissive version of [`freeze_struct`] that ignores the hash check when running in
+/// rust-analyzer since in some rare situations rust-analyzer will generate an incorrect hash code
+#[proc_macro_attribute]
+pub fn freeze_struct_ignore_ra(attr: TokenStream, tokens: TokenStream) -> TokenStream {
+    match freeze_struct_impl(attr, tokens, true) {
         Ok(item_struct) => item_struct.to_token_stream().into(),
         Err(err) => err.to_compile_error().into(),
     }
@@ -17,6 +32,7 @@ pub fn freeze_struct(attr: TokenStream, tokens: TokenStream) -> TokenStream {
 fn freeze_struct_impl(
     attr: impl Into<TokenStream2>,
     tokens: impl Into<TokenStream2>,
+    ignore_ra: bool,
 ) -> Result<ItemStruct> {
     let attr = attr.into();
     let tokens = tokens.into();
@@ -39,6 +55,10 @@ fn freeze_struct_impl(
     let mut visitor = CleanDocComments::new();
     visit_item_struct_mut(&mut visitor, &mut item_clone);
 
+    if ignore_ra && is_rust_analyzer() {
+        return Ok(item);
+    }
+
     if provided_hash_hex != calculated_hash_hex {
         return Err(Error::new_spanned(item,
             format!(
@@ -52,3 +72,10 @@ fn freeze_struct_impl(
     }
     Ok(item)
 }
+
+/// Returns true if the current build is being run by rust-analyzer.
+fn is_rust_analyzer() -> bool {
+    std::env::var("RUSTC_WRAPPER")
+        .map(|v| v.contains("rust-analyzer"))
+        .unwrap_or(false)
+}