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Fix #[import] macro: drop trailing unit to avoid clippy::unused_unit in user code #17

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Merged
colinrozzi merged 1 commit into from
May 9, 2026
Merged

Fix #[import] macro: drop trailing unit to avoid clippy::unused_unit in user code #17

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86 changes: 53 additions & 33 deletions crates/pack-guest-macros/src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -942,10 +942,12 @@ pub fn import(attr: TokenStream, item: TokenStream) -> TokenStream {
}
}

// Determine return type handling
let (return_type, has_return) = match output {
ReturnType::Default => (quote! { () }, false),
ReturnType::Type(_, ty) => (quote! { #ty }, true),
// Determine return type handling. When the import is `-> ()` (default),
// emit no `-> X` and no trailing unit expression — both trigger
// `clippy::unused_unit` in user code.
let (return_clause, has_return) = match output {
ReturnType::Default => (quote! {}, false),
ReturnType::Type(_, ty) => (quote! { -> #ty }, true),
};

// Build the input value - tuple of all parameters
Expand All @@ -963,17 +965,32 @@ pub fn import(attr: TokenStream, item: TokenStream) -> TokenStream {
}
};

// Build the return value handling
// Use FromValue::from_value() to support nested Option/Result types
let return_handling = if has_return {
// Build the body. When `has_return`, decode the result; otherwise drop it.
// Use FromValue::from_value() to support nested Option/Result types.
let body = if has_return {
quote! {
let input = #input_construction;
let result = packr_guest::__import_impl(
|in_ptr, in_len, out_ptr, out_cap| unsafe {
#raw_fn_name(in_ptr, in_len, out_ptr, out_cap)
},
input,
);
match packr_guest::FromValue::from_value(result) {
Ok(v) => v,
Err(_) => panic!("failed to convert import result"),
}
}
} else {
quote! { () }
quote! {
let input = #input_construction;
packr_guest::__import_impl(
|in_ptr, in_len, out_ptr, out_cap| unsafe {
#raw_fn_name(in_ptr, in_len, out_ptr, out_cap)
},
input,
);
}
};

// Generate the function signature parameters
Expand All @@ -991,15 +1008,8 @@ pub fn import(attr: TokenStream, item: TokenStream) -> TokenStream {
fn #raw_fn_name(in_ptr: i32, in_len: i32, out_ptr: i32, out_cap: i32) -> i32;
}

#fn_vis fn #fn_name(#(#fn_params),*) -> #return_type {
let input = #input_construction;
let result = packr_guest::__import_impl(
|in_ptr, in_len, out_ptr, out_cap| unsafe {
#raw_fn_name(in_ptr, in_len, out_ptr, out_cap)
},
input,
);
#return_handling
#fn_vis fn #fn_name(#(#fn_params),*) #return_clause {
#body
}
};

Expand Down Expand Up @@ -1408,10 +1418,12 @@ pub fn import_from(attr: TokenStream, item: TokenStream) -> TokenStream {
}
}

// Determine return type handling
let (return_type, has_return) = match output {
ReturnType::Default => (quote! { () }, false),
ReturnType::Type(_, ty) => (quote! { #ty }, true),
// Determine return type handling. When the import is `-> ()` (default),
// emit no `-> X` and no trailing unit expression — both trigger
// `clippy::unused_unit` in user code.
let (return_clause, has_return) = match output {
ReturnType::Default => (quote! {}, false),
ReturnType::Type(_, ty) => (quote! { -> #ty }, true),
};

// Build the input value - tuple of all parameters
Expand All @@ -1429,16 +1441,31 @@ pub fn import_from(attr: TokenStream, item: TokenStream) -> TokenStream {
}
};

// Build the return value handling
let return_handling = if has_return {
// Build the body. When `has_return`, decode the result; otherwise drop it.
let body = if has_return {
quote! {
let input = #input_construction;
let result = packr_guest::__import_impl(
|in_ptr, in_len, out_ptr, out_cap| unsafe {
#raw_fn_name(in_ptr, in_len, out_ptr, out_cap)
},
input,
);
match result.try_into() {
Ok(v) => v,
Err(_) => panic!("failed to convert import result from package '{}'", #package),
}
}
} else {
quote! { () }
quote! {
let input = #input_construction;
packr_guest::__import_impl(
|in_ptr, in_len, out_ptr, out_cap| unsafe {
#raw_fn_name(in_ptr, in_len, out_ptr, out_cap)
},
input,
);
}
};

// Generate the function signature parameters
Expand All @@ -1456,15 +1483,8 @@ pub fn import_from(attr: TokenStream, item: TokenStream) -> TokenStream {
fn #raw_fn_name(in_ptr: i32, in_len: i32, out_ptr: i32, out_cap: i32) -> i32;
}

#fn_vis fn #fn_name(#(#fn_params),*) -> #return_type {
let input = #input_construction;
let result = packr_guest::__import_impl(
|in_ptr, in_len, out_ptr, out_cap| unsafe {
#raw_fn_name(in_ptr, in_len, out_ptr, out_cap)
},
input,
);
#return_handling
#fn_vis fn #fn_name(#(#fn_params),*) #return_clause {
#body
}
};

Expand Down
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