Add support for schema(ignore) and param(ignore) (#1090)

Add support for `#[schema(ignore)]` for named field struct types
implementing `ToSchema` trait. Add support for `param(ignore)` for named
field structs implementing `IntoParams` trait. The ignored field will
not get serialized to the OpenAPI schema.

```rust
 #[derive(ToSchema)]
 struct SchemaIgnoredField {
     value: String,
     #[schema(ignore)]
     __this_is_private: String,
 }

 #[derive(IntoParams)]
 #[into_params(parameter_in = Query)]
 struct Params {
     name: String,
     #[param(ignore)]
     __this_is_private: String,
 }
```

Closes #795

utoipa-gen/CHANGELOG.md

@@ -4,6 +4,7 @@
 
 ### Added
 
+* Add support for `schema(ignore)` and `param(ignore)` (https://github.com/juhaku/utoipa/pull/1090)
 * Add support for `property_names` for object (https://github.com/juhaku/utoipa/pull/1084)
 * Add `bound` attribute for customizing generic impl bounds. (https://github.com/juhaku/utoipa/pull/1079)
 * Add auto collect schemas for utoipa-axum (https://github.com/juhaku/utoipa/pull/1072)

utoipa-gen/src/component/features.rs

@@ -102,6 +102,7 @@ pub enum Feature {
     ContentMediaType(attributes::ContentMediaType),
     Discriminator(attributes::Discriminator),
     Bound(attributes::Bound),
+    Ignore(attributes::Ignore),
     MultipleOf(validation::MultipleOf),
     Maximum(validation::Maximum),
     Minimum(validation::Minimum),
@@ -239,6 +240,7 @@ impl ToTokensDiagnostics for Feature {
                 let name = <attributes::Required as FeatureLike>::get_name();
                 quote! { .#name(#required) }
             }
+            Feature::Ignore(_) => return Err(Diagnostics::new("Feature::Ignore does not support ToTokens")),
         };
 
         tokens.extend(feature);
@@ -300,6 +302,7 @@ impl Display for Feature {
             Feature::ContentMediaType(content_media_type) => content_media_type.fmt(f),
             Feature::Discriminator(discriminator) => discriminator.fmt(f),
             Feature::Bound(bound) => bound.fmt(f),
+            Feature::Ignore(ignore) => ignore.fmt(f),
         }
     }
 }
@@ -349,6 +352,7 @@ impl Validatable for Feature {
             Feature::ContentMediaType(content_media_type) => content_media_type.is_validatable(),
             Feature::Discriminator(discriminator) => discriminator.is_validatable(),
             Feature::Bound(bound) => bound.is_validatable(),
+            Feature::Ignore(ignore) => ignore.is_validatable(),
         }
     }
 }
@@ -396,6 +400,7 @@ is_validatable! {
     attributes::ContentMediaType,
     attributes::Discriminator,
     attributes::Bound,
+    attributes::Ignore,
     validation::MultipleOf = true,
     validation::Maximum = true,
     validation::Minimum = true,
@@ -624,6 +629,7 @@ impl_feature_into_inner! {
     attributes::AdditionalProperties,
     attributes::Discriminator,
     attributes::Bound,
+    attributes::Ignore,
     validation::MultipleOf,
     validation::Maximum,
     validation::Minimum,

utoipa-gen/src/component/features/attributes.rs

@@ -982,3 +982,25 @@ impl From<Bound> for Feature {
         Feature::Bound(value)
     }
 }
+
+// Nothing to parse, it will be parsed true via `parse_features!` when defined as `ignore`
+impl_feature! {
+    #[derive(Clone)]
+    #[cfg_attr(feature = "debug", derive(Debug))]
+    pub struct Ignore;
+}
+
+impl Parse for Ignore {
+    fn parse(_: ParseStream, _: Ident) -> syn::Result<Self>
+    where
+        Self: std::marker::Sized,
+    {
+        Ok(Self)
+    }
+}
+
+impl From<Ignore> for Feature {
+    fn from(value: Ignore) -> Self {
+        Self::Ignore(value)
+    }
+}