support the "not": {} construction (#869)

Author: ahl

typify-impl/src/convert.rs

@@ -1619,6 +1619,25 @@ impl TypeSpace {
                 Ok((type_entry, metadata))
             }
 
+            // The permissive schema is equivalent to the `true` schema.
+            Schema::Object(SchemaObject {
+                metadata: _,
+                instance_type: None,
+                format: None,
+                enum_values: None,
+                const_value: None,
+                subschemas: None,
+                number: None,
+                string: None,
+                array: None,
+                object: None,
+                reference: None,
+                extensions: _,
+            }) => {
+                let (type_entry, _) = self.convert_schema(type_name, &Schema::Bool(false))?;
+                Ok((type_entry, metadata))
+            }
+
             // An explicit type and enumerated values.
             Schema::Object(
                 schema @ SchemaObject {

typify/tests/schemas/various-enums.json

@@ -168,6 +168,9 @@
     "NeverEver": {
       "not": true
     },
+    "NeverEverForever": {
+      "not": {}
+    },
     "AnyOfNothing": {
       "enum": []
     },

typify/tests/schemas/various-enums.rs

@@ -938,6 +938,33 @@ impl ::std::convert::From<&Self> for NeverEver {
         value.clone()
     }
 }
+#[doc = "`NeverEverForever`"]
+#[doc = r""]
+#[doc = r" <details><summary>JSON schema</summary>"]
+#[doc = r""]
+#[doc = r" ```json"]
+#[doc = "false"]
+#[doc = r" ```"]
+#[doc = r" </details>"]
+#[derive(
+    :: serde :: Deserialize,
+    :: serde :: Serialize,
+    Clone,
+    Copy,
+    Debug,
+    Eq,
+    Hash,
+    Ord,
+    PartialEq,
+    PartialOrd,
+)]
+#[serde(deny_unknown_fields)]
+pub enum NeverEverForever {}
+impl ::std::convert::From<&Self> for NeverEverForever {
+    fn from(value: &NeverEverForever) -> Self {
+        value.clone()
+    }
+}
 #[doc = "`NullStringEnumWithUnknownFormat`"]
 #[doc = r""]
 #[doc = r" <details><summary>JSON schema</summary>"]