ruma-api-macros: Add more error spans for request block

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

@@ -309,7 +309,7 @@ pub struct RawApi {
     /// The `metadata` section of the macro.
     pub metadata: RawMetadata,
     /// The `request` section of the macro.
-    pub request: Vec<Field>,
+    pub request: RawRequest,
     /// The `response` section of the macro.
     pub response: Vec<Field>,
 }
@@ -317,10 +317,7 @@ pub struct RawApi {
 impl Parse for RawApi {
     fn parse(input: ParseStream<'_>) -> syn::Result<Self> {
         let metadata = input.parse::<RawMetadata>()?;
-
+        let request = input.parse::<RawRequest>()?;
-        input.parse::<kw::request>()?;
-        let request;
-        braced!(request in input);
 
         input.parse::<kw::response>()?;
         let response;
@@ -328,10 +325,7 @@ impl Parse for RawApi {
 
         Ok(Self {
             metadata,
-            request: request
+            request,
-                .parse_terminated::<Field, Token![,]>(Field::parse_named)?
-                .into_iter()
-                .collect(),
             response: response
                 .parse_terminated::<Field, Token![,]>(Field::parse_named)?
                 .into_iter()
@@ -360,3 +354,24 @@ impl Parse for RawMetadata {
         })
     }
 }
+
+pub struct RawRequest {
+    pub request_kw: kw::request,
+    pub fields: Vec<Field>,
+}
+
+impl Parse for RawRequest {
+    fn parse(input: ParseStream<'_>) -> syn::Result<Self> {
+        let request_kw = input.parse::<kw::request>()?;
+        let fields;
+        braced!(fields in input);
+
+        Ok(Self {
+            request_kw,
+            fields: fields
+                .parse_terminated::<Field, Token![,]>(Field::parse_named)?
+                .into_iter()
+                .collect(),
+        })
+    }
+}

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

@@ -1,6 +1,6 @@
 //! Details of the `request` section of the procedural macro.
 
-use std::convert::TryFrom;
+use std::{convert::TryFrom, mem};
 
 use proc_macro2::TokenStream;
 use quote::{quote, quote_spanned, ToTokens};
@@ -8,7 +8,7 @@ use syn::{spanned::Spanned, Field, Ident};
 
 use crate::api::{
     attribute::{Meta, MetaNameValue},
-    strip_serde_attrs,
+    strip_serde_attrs, RawRequest,
 };
 
 /// The result of processing the `request` section of the macro.
@@ -121,66 +121,92 @@ impl Request {
     }
 }
 
-impl TryFrom<Vec<Field>> for Request {
+impl TryFrom<RawRequest> for Request {
     type Error = syn::Error;
 
-    fn try_from(fields: Vec<Field>) -> syn::Result<Self> {
+    fn try_from(raw: RawRequest) -> syn::Result<Self> {
-        let fields: Vec<_> = fields.into_iter().map(|mut field| {
+        let mut newtype_body_field = None;
+
+        let fields = raw
+            .fields
+            .into_iter()
+            .map(|mut field| {
                 let mut field_kind = None;
                 let mut header = None;
 
-            field.attrs.retain(|attr| {
+                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 => return true,
+                        None => {
+                            field.attrs.push(attr);
+                            continue;
+                        }
                     };
 
-                match meta {
+                    if field_kind.is_some() {
-                    Meta::Word(ident) => {
+                        return Err(syn::Error::new_spanned(
-                        assert!(
+                            attr,
-                            field_kind.is_none(),
+                            "There can only be one field kind attribute",
-                            "ruma_api! field kind can only be set once per field"
+                        ));
-                        );
+                    }
 
-                        field_kind = Some(match &ident.to_string()[..] {
+                    field_kind = Some(match meta {
-                            "body" => RequestFieldKind::NewtypeBody,
+                        Meta::Word(ident) => {
+                            match &ident.to_string()[..] {
+                                "body" => {
+                                    if let Some(f) = &newtype_body_field {
+                                        let mut error = syn::Error::new_spanned(
+                                            field,
+                                            "There can only be one newtype body field",
+                                        );
+                                        error.combine(syn::Error::new_spanned(
+                                            f,
+                                            "Previous newtype body field",
+                                        ));
+                                        return Err(error);
+                                    }
+
+                                    newtype_body_field = Some(field.clone());
+                                    RequestFieldKind::NewtypeBody
+                                }
                                 "path" => RequestFieldKind::Path,
                                 "query" => RequestFieldKind::Query,
-                            _ => panic!("ruma_api! single-word attribute on requests must be: body, path, or query"),
+                                _ => {
-                        });
+                                    return Err(syn::Error::new_spanned(
+                                        ident,
+                                        "Invalid #[ruma_api] argument, expected one of `body`, `path`, `query`",
+                                    ));
+                                }
+                            }
                         }
                         Meta::NameValue(MetaNameValue { name, value }) => {
-                        assert!(
+                            if name != "header" {
-                            name == "header",
+                                return Err(syn::Error::new_spanned(
-                            "ruma_api! name/value pair attribute on requests must be: header"
+                                    name,
-                        );
+                                    "Invalid #[ruma_api] argument with value, expected `header`"
-                        assert!(
+                                ));
-                            field_kind.is_none(),
+                            }
-                            "ruma_api! field kind can only be set once per field"
-                        );
 
                             header = Some(value);
-                        field_kind = Some(RequestFieldKind::Header);
+                            RequestFieldKind::Header
                         }
-                }
-
-                false
                     });
+                }
 
-            RequestField::new(field_kind.unwrap_or(RequestFieldKind::Body), field, header)
+                Ok(RequestField::new(
-        }).collect();
+                    field_kind.unwrap_or(RequestFieldKind::Body),
+                    field,
+                    header,
+                ))
+            })
+            .collect::<syn::Result<Vec<_>>>()?;
 
-        let num_body_fields = fields.iter().filter(|f| f.is_body()).count();
+        if newtype_body_field.is_some() && fields.iter().any(|f| f.is_body()) {
-        let num_newtype_body_fields = fields.iter().filter(|f| f.is_newtype_body()).count();
+            return Err(syn::Error::new_spanned(
-        assert!(
+                // TODO: raw,
-            num_newtype_body_fields <= 1,
+                raw.request_kw,
-            "ruma_api! request can only have one newtype body field"
+                "Can't have both a newtype body field and regular body fields",
-        );
+            ));
-        if num_newtype_body_fields == 1 {
-            assert!(
-                num_body_fields == 0,
-                "ruma_api! request can't have both regular body fields and a newtype body field"
-            );
         }
 
         Ok(Self { fields })
@@ -329,11 +355,6 @@ impl RequestField {
         self.kind() == RequestFieldKind::Header
     }
 
-    /// Whether or not this request field is a newtype body kind.
-    fn is_newtype_body(&self) -> bool {
-        self.kind() == RequestFieldKind::NewtypeBody
-    }
-
     /// Whether or not this request field is a path kind.
     fn is_path(&self) -> bool {
         self.kind() == RequestFieldKind::Path