[bindings] Pipe errors back from write_template_constructor

We can fail to resolve a part of a tuple, resulting in a panic in
write_template_constructor even if we're calling
`understood_c_type` with the intent of figuring out whether we can
print a type at all. Instead, we should pipe errors back and let
`understood_c_type` return false as a result.

diff --git a/c-bindings-gen/src/types.rs b/c-bindings-gen/src/types.rs
index e3ae3bdef4f9012fd2b7014466f419b7080c8e19..b5c17f3eb8bb900e7afed88416c28f2e357008a6 100644 (file)
--- a/c-bindings-gen/src/types.rs
+++ b/c-bindings-gen/src/types.rs
@@ -1720,7 +1720,7 @@ impl<'a, 'c: 'a> TypeResolver<'a, 'c> {
        // *** C Container Type Equivalent and alias Printing ***
        // ******************************************************
 
-       fn write_template_constructor<W: std::io::Write>(&mut self, w: &mut W, container_type: &str, mangled_container: &str, args: &Vec<&syn::Type>, generics: Option<&GenericTypes>, is_ref: bool) {
+       fn write_template_constructor<W: std::io::Write>(&mut self, w: &mut W, container_type: &str, mangled_container: &str, args: &Vec<&syn::Type>, generics: Option<&GenericTypes>, is_ref: bool) -> bool {
                if container_type == "Result" {
                        assert_eq!(args.len(), 2);
                        macro_rules! write_fn {
@@ -1761,7 +1761,7 @@ impl<'a, 'c: 'a> TypeResolver<'a, 'c> {
                        write!(w, "#[no_mangle]\npub extern \"C\" fn {}_new(", mangled_container).unwrap();
                        for (idx, gen) in args.iter().enumerate() {
                                write!(w, "{}{}: ", if idx != 0 { ", " } else { "" }, ('a' as u8 + idx as u8) as char).unwrap();
-                               assert!(self.write_c_type_intern(w, gen, None, false, false, false));
+                               if !self.write_c_type_intern(w, gen, None, false, false, false) { return false; }
                        }
                        writeln!(w, ") -> {} {{", mangled_container).unwrap();
                        write!(w, "\t{} {{ ", mangled_container).unwrap();
@@ -1772,6 +1772,7 @@ impl<'a, 'c: 'a> TypeResolver<'a, 'c> {
                } else {
                        writeln!(w, "").unwrap();
                }
+               true
        }
 
        fn write_template_generics<'b, W: std::io::Write>(&self, w: &mut W, args: &mut dyn Iterator<Item=&'b syn::Type>, generics: Option<&GenericTypes>, is_ref: bool, in_crate: bool) {
@@ -1850,9 +1851,8 @@ impl<'a, 'c: 'a> TypeResolver<'a, 'c> {
                        }
                }
        }
-       fn check_create_container(&mut self, mangled_container: String, container_type: &str, args: Vec<&syn::Type>, generics: Option<&GenericTypes>, is_ref: bool) {
+       fn check_create_container(&mut self, mangled_container: String, container_type: &str, args: Vec<&syn::Type>, generics: Option<&GenericTypes>, is_ref: bool) -> bool {
                if !self.crate_types.templates_defined.get(&mangled_container).is_some() {
-                       self.crate_types.templates_defined.insert(mangled_container.clone(), true);
                        let mut created_container: Vec<u8> = Vec::new();
 
                        write!(&mut created_container, "pub type {} = ", mangled_container).unwrap();
@@ -1865,10 +1865,14 @@ impl<'a, 'c: 'a> TypeResolver<'a, 'c> {
                        self.write_template_generics(&mut created_container, &mut args.iter().map(|t| *t), generics, is_ref, true);
                        writeln!(&mut created_container, ">;").unwrap();
 
-                       self.write_template_constructor(&mut created_container, container_type, &mangled_container, &args, generics, is_ref);
+                       if !self.write_template_constructor(&mut created_container, container_type, &mangled_container, &args, generics, is_ref) {
+                               return false;
+                       }
+                       self.crate_types.templates_defined.insert(mangled_container.clone(), true);
 
                        self.crate_types.template_file.write(&created_container).unwrap();
                }
+               true
        }
        fn path_to_generic_args(path: &syn::Path) -> Vec<&syn::Type> {
                if let syn::PathArguments::AngleBracketed(args) = &path.segments.iter().next().unwrap().arguments {
@@ -1885,45 +1889,46 @@ impl<'a, 'c: 'a> TypeResolver<'a, 'c> {
                for arg in args.iter() {
                        macro_rules! write_path {
                                ($p_arg: expr, $extra_write: expr) => {
-                                       let subtype = self.resolve_path(&$p_arg.path, generics);
-                                       if self.is_transparent_container(ident, is_ref) {
-                                               // We dont (yet) support primitives or containers inside transparent
-                                               // containers, so check for that first:
-                                               if self.is_primitive(&subtype) { return false; }
-                                               if self.is_known_container(&subtype, is_ref) { return false; }
-                                               if !in_type {
-                                                       if self.c_type_has_inner_from_path(&subtype) {
-                                                               if !self.write_c_path_intern(w, &$p_arg.path, generics, is_ref, is_mut, ptr_for_ref) { return false; }
+                                       if let Some(subtype) = self.maybe_resolve_path(&$p_arg.path, generics) {
+                                               if self.is_transparent_container(ident, is_ref) {
+                                                       // We dont (yet) support primitives or containers inside transparent
+                                                       // containers, so check for that first:
+                                                       if self.is_primitive(&subtype) { return false; }
+                                                       if self.is_known_container(&subtype, is_ref) { return false; }
+                                                       if !in_type {
+                                                               if self.c_type_has_inner_from_path(&subtype) {
+                                                                       if !self.write_c_path_intern(w, &$p_arg.path, generics, is_ref, is_mut, ptr_for_ref) { return false; }
+                                                               } else {
+                                                                       // Option<T> needs to be converted to a *mut T, ie mut ptr-for-ref
+                                                                       if !self.write_c_path_intern(w, &$p_arg.path, generics, true, true, true) { return false; }
+                                                               }
                                                        } else {
-                                                               // Option<T> needs to be converted to a *mut T, ie mut ptr-for-ref
-                                                               if !self.write_c_path_intern(w, &$p_arg.path, generics, true, true, true) { return false; }
+                                                               if $p_arg.path.segments.len() == 1 {
+                                                                       write!(w, "{}", $p_arg.path.segments.iter().next().unwrap().ident).unwrap();
+                                                               } else {
+                                                                       return false;
+                                                               }
                                                        }
-                                               } else {
-                                                       if $p_arg.path.segments.len() == 1 {
-                                                               write!(w, "{}", $p_arg.path.segments.iter().next().unwrap().ident).unwrap();
-                                                       } else {
+                                               } else if self.is_known_container(&subtype, is_ref) || self.is_transparent_container(&subtype, is_ref) {
+                                                       if !self.write_c_mangled_container_path_intern(w, Self::path_to_generic_args(&$p_arg.path), generics,
+                                                                       &subtype, is_ref, is_mut, ptr_for_ref, true) {
                                                                return false;
                                                        }
-                                               }
-                                       } else if self.is_known_container(&subtype, is_ref) || self.is_transparent_container(&subtype, is_ref) {
-                                               if !self.write_c_mangled_container_path_intern(w, Self::path_to_generic_args(&$p_arg.path), generics,
-                                                               &subtype, is_ref, is_mut, ptr_for_ref, true) {
-                                                       return false;
-                                               }
-                                               self.write_c_mangled_container_path_intern(&mut mangled_type, Self::path_to_generic_args(&$p_arg.path),
-                                                       generics, &subtype, is_ref, is_mut, ptr_for_ref, true);
-                                               if let Some(w2) = $extra_write as Option<&mut Vec<u8>> {
-                                                       self.write_c_mangled_container_path_intern(w2, Self::path_to_generic_args(&$p_arg.path),
+                                                       self.write_c_mangled_container_path_intern(&mut mangled_type, Self::path_to_generic_args(&$p_arg.path),
                                                                generics, &subtype, is_ref, is_mut, ptr_for_ref, true);
+                                                       if let Some(w2) = $extra_write as Option<&mut Vec<u8>> {
+                                                               self.write_c_mangled_container_path_intern(w2, Self::path_to_generic_args(&$p_arg.path),
+                                                                       generics, &subtype, is_ref, is_mut, ptr_for_ref, true);
+                                                       }
+                                               } else {
+                                                       let id = &&$p_arg.path.segments.iter().rev().next().unwrap().ident;
+                                                       write!(w, "{}", id).unwrap();
+                                                       write!(mangled_type, "{}", id).unwrap();
+                                                       if let Some(w2) = $extra_write as Option<&mut Vec<u8>> {
+                                                               write!(w2, "{}", id).unwrap();
+                                                       }
                                                }
-                                       } else {
-                                               let id = &&$p_arg.path.segments.iter().rev().next().unwrap().ident;
-                                               write!(w, "{}", id).unwrap();
-                                               write!(mangled_type, "{}", id).unwrap();
-                                               if let Some(w2) = $extra_write as Option<&mut Vec<u8>> {
-                                                       write!(w2, "{}", id).unwrap();
-                                               }
-                                       }
+                                       } else { return false; }
                                }
                        }
                        if let syn::Type::Tuple(tuple) = arg {
@@ -1952,8 +1957,10 @@ impl<'a, 'c: 'a> TypeResolver<'a, 'c> {
                                        write!(w, "Z").unwrap();
                                        write!(mangled_type, "Z").unwrap();
                                        write!(mangled_tuple_type, "Z").unwrap();
-                                       self.check_create_container(String::from_utf8(mangled_tuple_type).unwrap(),
-                                               &format!("{}Tuple", tuple.elems.len()), tuple.elems.iter().collect(), generics, is_ref);
+                                       if !self.check_create_container(String::from_utf8(mangled_tuple_type).unwrap(),
+                                                       &format!("{}Tuple", tuple.elems.len()), tuple.elems.iter().collect(), generics, is_ref) {
+                                               return false;
+                                       }
                                }
                        } else if let syn::Type::Path(p_arg) = arg {
                                write_path!(p_arg, None);
@@ -1987,8 +1994,7 @@ impl<'a, 'c: 'a> TypeResolver<'a, 'c> {
                write!(mangled_type, "Z").unwrap();
 
                // Make sure the type is actually defined:
-               self.check_create_container(String::from_utf8(mangled_type).unwrap(), ident, args, generics, is_ref);
-               true
+               self.check_create_container(String::from_utf8(mangled_type).unwrap(), ident, args, generics, is_ref)
        }
        fn write_c_mangled_container_path<W: std::io::Write>(&mut self, w: &mut W, args: Vec<&syn::Type>, generics: Option<&GenericTypes>, ident: &str, is_ref: bool, is_mut: bool, ptr_for_ref: bool) -> bool {
                if !self.is_transparent_container(ident, is_ref) {
@@ -2098,8 +2104,7 @@ impl<'a, 'c: 'a> TypeResolver<'a, 'c> {
                                                        format!("CVec_{}Z", id)
                                                } else { return false; };
                                                write!(w, "{}::{}", Self::generated_container_path(), mangled_container).unwrap();
-                                               self.check_create_container(mangled_container, "Vec", vec![&*r.elem], generics, false);
-                                               true
+                                               self.check_create_container(mangled_container, "Vec", vec![&*r.elem], generics, false)
                                        } else { false }
                                } else if let syn::Type::Tuple(_) = &*s.elem {
                                        let mut args = syn::punctuated::Punctuated::new();