fix(schemas): Fix 'metadata' JSON Schema

Found this when looking into #15030

Author: epage

crates/cargo-util-schemas/manifest.schema.json

@@ -621,40 +621,7 @@
         }
       ]
     },
-    "TomlValue": {
-      "type": "object",
-      "properties": {
-        "string": {
-          "type": "string"
-        },
-        "integer": {
-          "type": "integer",
-          "format": "int64"
-        },
-        "float": {
-          "type": "number",
-          "format": "double"
-        },
-        "boolean": {
-          "type": "boolean"
-        },
-        "datetime": {
-          "type": "string"
-        },
-        "array": {
-          "type": "array",
-          "items": {
-            "$ref": "#/definitions/TomlValue"
-          }
-        },
-        "table": {
-          "type": "object",
-          "additionalProperties": {
-            "$ref": "#/definitions/TomlValue"
-          }
-        }
-      }
-    },
+    "TomlValue": true,
     "TomlTarget": {
       "type": "object",
       "properties": {

crates/cargo-util-schemas/src/schema.rs

@@ -2,7 +2,6 @@ use schemars::JsonSchema;
 
 use serde::{Deserialize, Serialize};
 
-use std::collections::HashMap;
 use std::string::String;
 
 use toml::Value as TomlValue;
@@ -16,39 +15,7 @@ impl JsonSchema for TomlValueWrapper {
     }
 
     fn json_schema(gen: &mut schemars::gen::SchemaGenerator) -> schemars::schema::Schema {
-        use schemars::schema::*;
-
-        SchemaObject {
-            instance_type: Some(InstanceType::Object.into()),
-            object: Some(Box::new(ObjectValidation {
-                properties: [
-                    (
-                        "string".to_string(),
-                        gen.subschema_for::<std::string::String>(),
-                    ),
-                    ("integer".to_string(), gen.subschema_for::<i64>()),
-                    ("float".to_string(), gen.subschema_for::<f64>()),
-                    ("boolean".to_string(), gen.subschema_for::<bool>()),
-                    (
-                        "datetime".to_string(),
-                        gen.subschema_for::<std::string::String>(),
-                    ), // Assuming datetime is represented as a string
-                    (
-                        "array".to_string(),
-                        gen.subschema_for::<Vec<TomlValueWrapper>>(),
-                    ),
-                    (
-                        "table".to_string(),
-                        gen.subschema_for::<HashMap<std::string::String, TomlValueWrapper>>(),
-                    ),
-                ]
-                .iter()
-                .cloned()
-                .collect(),
-                ..Default::default()
-            })),
-            ..Default::default()
-        }
-        .into()
+        // HACK: this is both more and less permissive than `TomlValue` but its close
+        gen.subschema_for::<serde_json::Value>().into()
     }
 }