Don't include number format in schema for value

Guessing the format for serde_json::Number can be very misleading, so let's not

schemars/src/ser.rs

@@ -35,6 +35,18 @@ macro_rules! forward_to_subschema_for {
     };
 }
 
+macro_rules! return_instance_type {
+    ($fn:ident, $ty:ty, $instance_type:ident) => {
+        fn $fn(self, _value: $ty) -> Result<Self::Ok, Self::Error> {
+            Ok(SchemaObject {
+                instance_type: Some(InstanceType::$instance_type.into()),
+                ..Default::default()
+            }
+            .into())
+        }
+    };
+}
+
 impl<'a> serde::Serializer for Serializer<'a> {
     type Ok = Schema;
     type Error = Error;
@@ -47,19 +59,20 @@ impl<'a> serde::Serializer for Serializer<'a> {
     type SerializeStruct = SerializeMap<'a>;
     type SerializeStructVariant = Self;
 
+    return_instance_type!(serialize_i8, i8, Integer);
+    return_instance_type!(serialize_i16, i16, Integer);
+    return_instance_type!(serialize_i32, i32, Integer);
+    return_instance_type!(serialize_i64, i64, Integer);
+    return_instance_type!(serialize_i128, i128, Integer);
+    return_instance_type!(serialize_u8, u8, Integer);
+    return_instance_type!(serialize_u16, u16, Integer);
+    return_instance_type!(serialize_u32, u32, Integer);
+    return_instance_type!(serialize_u64, u64, Integer);
+    return_instance_type!(serialize_u128, u128, Integer);
+    return_instance_type!(serialize_f32, f32, Number);
+    return_instance_type!(serialize_f64, f64, Number);
+
     forward_to_subschema_for!(serialize_bool, bool);
-    forward_to_subschema_for!(serialize_i8, i8);
-    forward_to_subschema_for!(serialize_i16, i16);
-    forward_to_subschema_for!(serialize_i32, i32);
-    forward_to_subschema_for!(serialize_i64, i64);
-    forward_to_subschema_for!(serialize_i128, i128);
-    forward_to_subschema_for!(serialize_u8, u8);
-    forward_to_subschema_for!(serialize_u16, u16);
-    forward_to_subschema_for!(serialize_u32, u32);
-    forward_to_subschema_for!(serialize_u64, u64);
-    forward_to_subschema_for!(serialize_u128, u128);
-    forward_to_subschema_for!(serialize_f32, f32);
-    forward_to_subschema_for!(serialize_f64, f64);
     forward_to_subschema_for!(serialize_char, char);
     forward_to_subschema_for!(serialize_str, &str);
     forward_to_subschema_for!(serialize_bytes, &[u8]);
@@ -68,7 +81,7 @@ impl<'a> serde::Serializer for Serializer<'a> {
     where
         T: Display,
     {
-        Ok(self.gen.subschema_for::<String>())
+        Ok(self.gen.subschema_for::<&str>())
     }
 
     fn collect_map<K, V, I>(self, iter: I) -> Result<Self::Ok, Self::Error>
@@ -111,6 +124,10 @@ impl<'a> serde::Serializer for Serializer<'a> {
         Ok(self.gen.subschema_for::<Option<Value>>())
     }
 
+    fn serialize_unit(self) -> Result<Self::Ok, Self::Error> {
+        self.serialize_none()
+    }
+
     fn serialize_some<T: ?Sized>(mut self, value: &T) -> Result<Self::Ok, Self::Error>
     where
         T: serde::Serialize,
@@ -166,12 +183,8 @@ impl<'a> serde::Serializer for Serializer<'a> {
         Ok(schema)
     }
 
-    fn serialize_unit(self) -> Result<Self::Ok, Self::Error> {
-        Ok(self.gen.subschema_for::<()>())
-    }
-
     fn serialize_unit_struct(self, _name: &'static str) -> Result<Self::Ok, Self::Error> {
-        self.serialize_unit()
+        Ok(self.gen.subschema_for::<()>())
     }
 
     fn serialize_unit_variant(

schemars/tests/expected/from_json_value.json

@@ -0,0 +1,49 @@
+{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "examples": [
+    {
+      "bool": true,
+      "minusOne": -1,
+      "null": null,
+      "object": {
+        "array": [
+          "foo",
+          "bar"
+        ]
+      },
+      "one": 1,
+      "zero": 0,
+      "zeroPointZero": 0.0
+    }
+  ],
+  "type": "object",
+  "properties": {
+    "bool": {
+      "type": "boolean"
+    },
+    "minusOne": {
+      "type": "integer"
+    },
+    "null": true,
+    "object": {
+      "type": "object",
+      "properties": {
+        "array": {
+          "type": "array",
+          "items": {
+            "type": "string"
+          }
+        }
+      }
+    },
+    "one": {
+      "type": "integer"
+    },
+    "zero": {
+      "type": "integer"
+    },
+    "zeroPointZero": {
+      "type": "number"
+    }
+  }
+}

schemars/tests/expected/from_value_2019_09.json

@@ -26,8 +26,7 @@
   "type": "object",
   "properties": {
     "myInt": {
-      "type": "integer",
-      "format": "int32"
+      "type": "integer"
     },
     "myBool": {
       "type": "boolean"
@@ -39,8 +38,7 @@
         "my_map": {
           "type": "object",
           "additionalProperties": {
-            "type": "number",
-            "format": "double"
+            "type": "number"
           }
         },
         "my_vec": {
@@ -66,9 +64,7 @@
               "minLength": 1
             },
             {
-              "type": "integer",
-              "format": "uint8",
-              "minimum": 0.0
+              "type": "integer"
             }
           ],
           "maxItems": 2,

schemars/tests/expected/from_value_draft07.json

@@ -26,8 +26,7 @@
   "type": "object",
   "properties": {
     "myInt": {
-      "type": "integer",
-      "format": "int32"
+      "type": "integer"
     },
     "myBool": {
       "type": "boolean"
@@ -39,8 +38,7 @@
         "my_map": {
           "type": "object",
           "additionalProperties": {
-            "type": "number",
-            "format": "double"
+            "type": "number"
           }
         },
         "my_vec": {
@@ -66,9 +64,7 @@
               "minLength": 1
             },
             {
-              "type": "integer",
-              "format": "uint8",
-              "minimum": 0.0
+              "type": "integer"
             }
           ],
           "maxItems": 2,

schemars/tests/expected/from_value_openapi3.json

@@ -4,8 +4,7 @@
   "type": "object",
   "properties": {
     "myInt": {
-      "type": "integer",
-      "format": "int32"
+      "type": "integer"
     },
     "myBool": {
       "type": "boolean"
@@ -19,8 +18,7 @@
         "my_map": {
           "type": "object",
           "additionalProperties": {
-            "type": "number",
-            "format": "double"
+            "type": "number"
           }
         },
         "my_vec": {
@@ -46,9 +44,7 @@
               "minLength": 1
             },
             {
-              "type": "integer",
-              "format": "uint8",
-              "minimum": 0.0
+              "type": "integer"
             }
           ],
           "maxItems": 2,

schemars/tests/from_value.rs

@@ -1,8 +1,7 @@
 mod util;
-use std::collections::HashMap;
-
-use schemars::gen::SchemaSettings;
+use schemars::gen::{SchemaGenerator, SchemaSettings};
 use serde::Serialize;
+use std::collections::HashMap;
 use util::*;
 
 #[derive(Serialize)]
@@ -75,3 +74,21 @@ fn schema_from_value_matches_openapi3() -> TestResult {
 
     test_schema(&actual, "from_value_openapi3")
 }
+
+#[test]
+fn schema_from_json_value() -> TestResult {
+    let gen = SchemaGenerator::default();
+    let actual = gen.into_root_schema_for_value(&serde_json::json!({
+        "zero": 0,
+        "one": 1,
+        "minusOne": -1,
+        "zeroPointZero": 0.0,
+        "bool": true,
+        "null": null,
+        "object": {
+            "array": ["foo", "bar"]
+        },
+    }))?;
+
+    test_schema(&actual, "from_json_value")
+}