Set "required" schema attribute

schemars/src/schema.rs

@@ -3,6 +3,7 @@ use crate::{MakeSchema, MakeSchemaError, Result};
 use serde::{Deserialize, Serialize};
 use serde_json::Value;
 use std::collections::BTreeMap as Map;
+use std::collections::BTreeSet as Set;
 
 #[derive(Serialize, Deserialize, Debug, Clone, PartialEq, MakeSchema)]
 #[serde(untagged)]
@@ -30,13 +31,13 @@ impl From<SchemaRef> for Schema {
     }
 }
 
-fn extend<A, E: Extend<A>>(mut a: E, b: impl IntoIterator<Item = A>) -> E {
-    a.extend(b);
-    a
-}
-
 impl Schema {
     pub fn flatten(self, other: Self) -> Result {
+        fn extend<A, E: Extend<A>>(mut a: E, b: impl IntoIterator<Item = A>) -> E {
+            a.extend(b);
+            a
+        }
+
         let s1 = self.ensure_flattenable()?;
         let s2 = other.ensure_flattenable()?;
         Ok(Schema::Object(SchemaObject {
@@ -112,8 +113,8 @@ pub struct SchemaObject {
     pub items: Option<SingleOrVec<Schema>>,
     #[serde(skip_serializing_if = "Map::is_empty")]
     pub properties: Map<String, Schema>,
-    #[serde(skip_serializing_if = "Vec::is_empty")]
+    #[serde(skip_serializing_if = "Set::is_empty")]
-    pub required: Vec<String>,
+    pub required: Set<String>,
     #[serde(skip_serializing_if = "Option::is_none")]
     pub all_of: Option<Vec<Schema>>,
     #[serde(skip_serializing_if = "Option::is_none")]

schemars/tests/expected/property-name-struct.json

@@ -12,5 +12,10 @@
     "new_name_2": {
       "type": "integer"
     }
-  }
+  },
+  "required": [
+    "camelCase",
+    "new_name_1",
+    "new_name_2"
+  ]
 }

schemars/tests/expected/schema-name-custom.json

@@ -22,6 +22,13 @@
       }
     }
   },
+  "required": [
+    "inner",
+    "t",
+    "u",
+    "v",
+    "w"
+  ],
   "definitions": {
     "another-new-name": {
       "type": "object"

schemars/tests/expected/schema-name-default.json

@@ -22,6 +22,13 @@
       }
     }
   },
+  "required": [
+    "inner",
+    "t",
+    "u",
+    "v",
+    "w"
+  ],
   "definitions": {
     "MySimpleStruct": {
       "type": "object"

schemars/tests/expected/schema-openapi3.json

@@ -151,7 +151,10 @@
         "$ref": {
           "type": "string"
         }
-      }
+      },
+      "required": [
+        "$ref"
+      ]
     },
     "SingleOrVec_For_InstanceType": {
       "anyOf": [

schemars/tests/expected/schema.json

@@ -187,7 +187,10 @@
         "$ref": {
           "type": "string"
         }
-      }
+      },
+      "required": [
+        "$ref"
+      ]
     },
     "SingleOrVec_For_InstanceType": {
       "anyOf": [

schemars_derive/src/lib.rs

@@ -9,7 +9,7 @@ mod preprocess;
 
 use proc_macro2::{Span, TokenStream};
 use serde_derive_internals::ast::{Container, Data, Field, Style, Variant};
-use serde_derive_internals::attr::{self, EnumTag};
+use serde_derive_internals::attr::{self, Default as SerdeDefault, EnumTag};
 use serde_derive_internals::{Ctxt, Derive};
 use syn::spanned::Spanned;
 use syn::DeriveInput;
@@ -28,7 +28,7 @@ pub fn derive_make_schema(input: proc_macro::TokenStream) -> proc_macro::TokenSt
     }
 
     let schema = match cont.data {
-        Data::Struct(Style::Struct, ref fields) => schema_for_struct(fields),
+        Data::Struct(Style::Struct, ref fields) => schema_for_struct(fields, &cont.attrs),
         Data::Enum(ref variants) => schema_for_enum(variants, &cont.attrs),
         _ => unimplemented!("work in progress!"),
     };
@@ -102,13 +102,13 @@ fn is_unit_variant(v: &&Variant) -> bool {
 
 fn schema_for_enum(variants: &[Variant], cattrs: &attr::Container) -> TokenStream {
     match cattrs.tag() {
-        EnumTag::External => schema_for_external_tagged_enum(variants),
+        EnumTag::External => schema_for_external_tagged_enum(variants, cattrs),
-        EnumTag::None => schema_for_untagged_enum(variants),
+        EnumTag::None => schema_for_untagged_enum(variants, cattrs),
         _ => unimplemented!("Adjacent/internal tagged enums not yet supported."),
     }
 }
 
-fn schema_for_external_tagged_enum(variants: &[Variant]) -> TokenStream {
+fn schema_for_external_tagged_enum(variants: &[Variant], cattrs: &attr::Container) -> TokenStream {
     let (unit_variants, complex_variants): (Vec<_>, Vec<_>) =
         variants.into_iter().partition(is_unit_variant);
     let unit_count = unit_variants.len();
@@ -131,7 +131,7 @@ fn schema_for_external_tagged_enum(variants: &[Variant]) -> TokenStream {
 
     schemas.extend(complex_variants.into_iter().map(|variant| {
         let name = variant.attrs.name().deserialize_name();
-        let sub_schema = schema_for_untagged_enum_variant(variant);
+        let sub_schema = schema_for_untagged_enum_variant(variant, cattrs);
         wrap_schema_fields(quote! {
             instance_type: Some(schemars::schema::InstanceType::Object.into()),
             properties: {
@@ -139,6 +139,7 @@ fn schema_for_external_tagged_enum(variants: &[Variant]) -> TokenStream {
                 props.insert(#name.to_owned(), #sub_schema);
                 props
             },
+            required: vec![#name.to_owned()],
         })
     }));
 
@@ -147,15 +148,17 @@ fn schema_for_external_tagged_enum(variants: &[Variant]) -> TokenStream {
     })
 }
 
-fn schema_for_untagged_enum(variants: &[Variant]) -> TokenStream {
+fn schema_for_untagged_enum(variants: &[Variant], cattrs: &attr::Container) -> TokenStream {
-    let schemas = variants.into_iter().map(schema_for_untagged_enum_variant);
+    let schemas = variants
+        .into_iter()
+        .map(|v| schema_for_untagged_enum_variant(v, cattrs));
 
     wrap_schema_fields(quote! {
         any_of: Some(vec![#(#schemas),*]),
     })
 }
 
-fn schema_for_untagged_enum_variant(variant: &Variant) -> TokenStream {
+fn schema_for_untagged_enum_variant(variant: &Variant, cattrs: &attr::Container) -> TokenStream {
     match variant.style {
         Style::Unit => quote! {
             gen.subschema_for::<()>()?
@@ -173,19 +176,25 @@ fn schema_for_untagged_enum_variant(variant: &Variant) -> TokenStream {
                 gen.subschema_for::<(#(#types),*)>()?
             }
         }
-        Style::Struct => schema_for_struct(&variant.fields),
+        Style::Struct => schema_for_struct(&variant.fields, cattrs),
     }
 }
 
-fn schema_for_struct(fields: &[Field]) -> TokenStream {
+fn schema_for_struct(fields: &[Field], cattrs: &attr::Container) -> TokenStream {
     let (nested, flat): (Vec<_>, Vec<_>) = fields.iter().partition(|f| !f.attrs.flatten());
+    let container_has_default = has_default(cattrs.default());
+    let mut required = Vec::new();
     let recurse = nested.iter().map(|f| {
         let name = f.attrs.name().deserialize_name();
+        if !container_has_default && !has_default(f.attrs.default()) {
+            required.push(name.clone());
+        }
         let ty = f.ty;
         quote_spanned! {f.original.span()=>
             props.insert(#name.to_owned(), gen.subschema_for::<#ty>()?);
         }
     });
+
     let schema = wrap_schema_fields(quote! {
         instance_type: Some(schemars::schema::InstanceType::Object.into()),
         properties: {
@@ -193,6 +202,11 @@ fn schema_for_struct(fields: &[Field]) -> TokenStream {
             #(#recurse)*
             props
         },
+        required: {
+            let mut required = std::collections::BTreeSet::new();
+            #(required.insert(#required.to_owned());)*
+            required
+        },
     });
 
     let flattens = flat.iter().map(|f| {
@@ -206,3 +220,10 @@ fn schema_for_struct(fields: &[Field]) -> TokenStream {
         #schema #(#flattens)*
     }
 }
+
+fn has_default(d: &SerdeDefault) -> bool {
+    match d {
+        SerdeDefault::None => false,
+        _ => true,
+    }
+}