ruma-api-macros: Rewrite a few leftover errors without spans

ruma-api-macros/src/api/attribute.rs

@@ -28,16 +28,15 @@ impl Meta {
     /// # Panics
     ///
     /// Panics if the given attribute is a ruma_api attribute, but fails to parse.
-    pub fn from_attribute(attr: &syn::Attribute) -> Option<Self> {
+    pub fn from_attribute(attr: &syn::Attribute) -> syn::Result<Option<Self>> {
         match &attr.path {
             syn::Path {
                 leading_colon: None,
                 segments,
-            } if segments.len() == 1 && segments[0].ident == "ruma_api" => Some(
-                attr.parse_args()
-                    .expect("ruma_api! could not parse request field attributes"),
-            ),
-            _ => None,
+            } if segments.len() == 1 && segments[0].ident == "ruma_api" => {
+                attr.parse_args().map(Some)
+            }
+            _ => Ok(None),
         }
     }
 }

ruma-api-macros/src/api/mod.rs

@@ -46,13 +46,32 @@ impl TryFrom<RawApi> for Api {
             response: raw_api.response.try_into()?,
         };
 
-        assert!(
-            !(res.metadata.method == "GET"
-                && (res.request.has_body_fields() || res.request.newtype_body_field().is_some())),
-            "GET endpoints can't have body fields"
-        );
+        let newtype_body_field = res.request.newtype_body_field();
+        if res.metadata.method == "GET"
+            && (res.request.has_body_fields() || newtype_body_field.is_some())
+        {
+            let mut combined_error: Option<syn::Error> = None;
+            let mut add_error = |field| {
+                let error = syn::Error::new_spanned(field, "GET endpoints can't have body fields");
+                if let Some(combined_error_ref) = &mut combined_error {
+                    combined_error_ref.combine(error);
+                } else {
+                    combined_error = Some(error);
+                }
+            };
 
-        Ok(res)
+            for field in res.request.body_fields() {
+                add_error(field);
+            }
+
+            if let Some(field) = newtype_body_field {
+                add_error(field);
+            }
+
+            Err(combined_error.unwrap())
+        } else {
+            Ok(res)
+        }
     }
 }
 

ruma-api-macros/src/api/request.rs

@@ -23,7 +23,7 @@ impl Request {
         let append_stmts = self.header_fields().map(|request_field| {
             let (field, header_name) = match request_field {
                 RequestField::Header(field, header_name) => (field, header_name),
-                _ => panic!("expected request field to be header variant"),
+                _ => unreachable!("expected request field to be header variant"),
             };
 
             let field_name = &field.ident;
@@ -62,6 +62,11 @@ impl Request {
         self.fields.iter().any(|field| field.is_query())
     }
 
+    /// Produces an iterator over all the body fields.
+    pub fn body_fields(&self) -> impl Iterator<Item = &Field> {
+        self.fields.iter().filter_map(|field| field.as_body_field())
+    }
+
     /// Produces an iterator over all the header fields.
     pub fn header_fields(&self) -> impl Iterator<Item = &RequestField> {
         self.fields.iter().filter(|field| field.is_header())
@@ -135,7 +140,7 @@ impl TryFrom<RawRequest> for Request {
                 let mut header = None;
 
                 for attr in mem::replace(&mut field.attrs, Vec::new()) {
-                    let meta = match Meta::from_attribute(&attr) {
+                    let meta = match Meta::from_attribute(&attr)? {
                         Some(m) => m,
                         None => {
                             field.attrs.push(attr);

ruma-api-macros/src/api/response.rs

@@ -105,7 +105,7 @@ impl TryFrom<RawResponse> for Response {
                 let mut header = None;
 
                 for attr in mem::replace(&mut field.attrs, Vec::new()) {
-                    let meta = match Meta::from_attribute(&attr) {
+                    let meta = match Meta::from_attribute(&attr)? {
                         Some(m) => m,
                         None => {
                             field.attrs.push(attr);