Combine const and enum errors into a single message

src/error-handlers/constAndEnum.js

@@ -0,0 +1,96 @@
+import { getSchema } from "@hyperjump/json-schema/experimental";
+import * as Schema from "@hyperjump/browser";
+import * as Instance from "@hyperjump/json-schema/instance/experimental";
+import jsonStringify from "json-stringify-deterministic";
+
+/**
+ * @import { ErrorHandler, ErrorObject, Json } from "../index.d.ts"
+ */
+
+/**
+ * @typedef {{
+ *   allowedValues: Json[];
+ *   schemaLocation: string;
+ * }} Constraint
+ */
+
+/** @type {ErrorHandler} */
+const constAndEnumErrorHandler = async (normalizedErrors, instance, localization) => {
+  /** @type {ErrorObject[]} */
+  const errors = [];
+
+  /** @type {Constraint[]} */
+  const constraints = [];
+  let hasFailure = false;
+
+  for (const schemaLocation in normalizedErrors["https://json-schema.org/keyword/const"]) {
+    const passed = normalizedErrors["https://json-schema.org/keyword/const"][schemaLocation] === true;
+    if (!passed) {
+      hasFailure = true;
+    }
+    const keyword = await getSchema(schemaLocation);
+    constraints.push({
+      allowedValues: [Schema.value(keyword)],
+      schemaLocation
+    });
+  }
+
+  for (const schemaLocation in normalizedErrors["https://json-schema.org/keyword/enum"]) {
+    const passed = normalizedErrors["https://json-schema.org/keyword/enum"][schemaLocation] === true;
+    if (!passed) {
+      hasFailure = true;
+    }
+    const keyword = await getSchema(schemaLocation);
+    constraints.push({
+      allowedValues: Schema.value(keyword),
+      schemaLocation
+    });
+  }
+
+  if (!hasFailure || constraints.length === 0) {
+    return errors;
+  }
+
+  const mostConstraining = constraints.reduce((min, c) =>
+    c.allowedValues.length < min.allowedValues.length ? c : min
+  );
+
+  let intersectionKeys = new Set(mostConstraining.allowedValues.map(toKey));
+  for (let i = 1; i < constraints.length; i++) {
+    const otherKeys = new Set(constraints[i].allowedValues.map(toKey));
+    intersectionKeys = new Set([...intersectionKeys].filter((k) => otherKeys.has(k)));
+  }
+
+  // eslint-disable-next-line @typescript-eslint/no-unsafe-return
+  const intersection = /** @type {Json[]} */ ([...intersectionKeys].map((k) => JSON.parse(k)));
+
+  const instanceLocation = Instance.uri(instance);
+  if (intersection.length === 0) {
+    errors.push({
+      message: localization.getBooleanSchemaErrorMessage(),
+      instanceLocation,
+      schemaLocations: constraints.map((c) => c.schemaLocation)
+    });
+  } else if (intersection.length === 1) {
+    errors.push({
+      message: localization.getConstErrorMessage(intersection[0]),
+      instanceLocation,
+      schemaLocations: [mostConstraining.schemaLocation]
+    });
+  } else {
+    errors.push({
+      message: localization.getEnumErrorMessage(intersection),
+      instanceLocation,
+      schemaLocations: [mostConstraining.schemaLocation]
+    });
+  }
+  return errors;
+};
+
+/**
+ * @param {Json} val
+ * @returns {string}
+ */
+const toKey = (val) => jsonStringify(val);
+
+export default constAndEnumErrorHandler;

src/index.js

@@ -54,11 +54,10 @@ import unknownNormalizationHandler from "./normalization-handlers/unknown.js";
 // Error Handlers
 import anyOfErrorHandler from "./error-handlers/anyOf.js";
 import booleanSchemaErrorHandler from "./error-handlers/boolean-schema.js";
-import constErrorHandler from "./error-handlers/const.js";
+import constAndEnumErrorHandler from "./error-handlers/constAndEnum.js";
 import containsErrorHandler from "./error-handlers/contains.js";
 import dependenciesErrorHandler from "./error-handlers/draft-04/dependencies.js";
 import dependentRequiredErrorHandler from "./error-handlers/dependentRequired.js";
-import enumErrorHandler from "./error-handlers/enum.js";
 import exclusiveMaximumErrorHandler from "./error-handlers/exclusiveMaximum.js";
 import exclusiveMinimumErrorHandler from "./error-handlers/exclusiveMinimum.js";
 import formatErrorHandler from "./error-handlers/format.js";
@@ -139,11 +138,10 @@ setNormalizationHandler("https://json-schema.org/keyword/unknown", unknownNormal
 
 addErrorHandler(anyOfErrorHandler);
 addErrorHandler(booleanSchemaErrorHandler);
-addErrorHandler(constErrorHandler);
+addErrorHandler(constAndEnumErrorHandler);
 addErrorHandler(containsErrorHandler);
 addErrorHandler(dependenciesErrorHandler);
 addErrorHandler(dependentRequiredErrorHandler);
-addErrorHandler(enumErrorHandler);
 addErrorHandler(exclusiveMaximumErrorHandler);
 addErrorHandler(exclusiveMinimumErrorHandler);
 addErrorHandler(formatErrorHandler);

src/test-suite/tests/const.json

@@ -29,6 +29,25 @@
       },
       "instance": 42,
       "errors": []
+    },
+    {
+      "description": "contradictory const - empty intersection",
+      "compatibility": "6",
+      "schema": {
+        "allOf": [
+          { "const": "a" },
+          { "const": "b" }
+        ]
+      },
+      "instance": "a",
+      "errors": [
+        {
+          "messageId": "boolean-schema-message",
+          "messageParams": {},
+          "instanceLocation": "#",
+          "schemaLocations": ["#/allOf/0/const", "#/allOf/1/const"]
+        }
+      ]
     }
   ]
 }

src/test-suite/tests/constAndEnum.json

@@ -0,0 +1,48 @@
+{
+  "$schema": "../test-suite.schema.json",
+
+  "description": "Combined const and enum constraints",
+  "tests": [
+    {
+      "description": "const with enum constraints (combined)",
+      "compatibility": "6",
+      "schema": {
+        "allOf": [
+          { "enum": ["a", "b", "c"] },
+          { "enum": ["a", "b"] },
+          { "const": "a" }
+        ]
+      },
+      "instance": "x",
+      "errors": [
+        {
+          "messageId": "const-message",
+          "messageParams": { "expected": "\"a\"" },
+          "instanceLocation": "#",
+          "schemaLocations": ["#/allOf/2/const"]
+        }
+      ]
+    },
+    {
+      "description": "enum with const - deterministic key order",
+      "compatibility": "6",
+      "schema": {
+        "allOf": [
+          { "enum": [{"a": 1, "b": 2}, {"c": 3}] },
+          { "const": {"b": 2, "a": 1} }
+        ]
+      },
+      "instance": "x",
+      "errors": [
+        {
+          "messageId": "const-message",
+          "messageParams": {
+            "expected": "{\n  \"a\": 1,\n  \"b\": 2\n}"
+          },
+          "instanceLocation": "#",
+          "schemaLocations": ["#/allOf/1/const"]
+        }
+      ]
+    }
+  ]
+}

src/test-suite/tests/enum.json

@@ -21,13 +21,53 @@
         }
       ]
     },
+    {
+      "description": "multiple enum constraints (combined)",
+      "schema": {
+        "allOf": [
+          { "enum": ["a", "b", "c"] },
+          { "enum": ["a", "b"] }
+        ]
+      },
+      "instance": "x",
+      "errors": [
+        {
+          "messageId": "enum-message",
+          "messageParams": {
+            "expected": { "or": ["\"a\"", "\"b\""] },
+            "count": 2
+          },
+          "instanceLocation": "#",
+          "schemaLocations": ["#/allOf/1/enum"]
+        }
+      ]
+    },
     {
       "description": "enum pass",
       "schema": {
         "enum": ["foo", "bar"]
       },
       "instance": "foo",
       "errors": []
+    },
+    {
+      "description": "contradictory enum - empty intersection",
+      "compatibility": "6",
+      "schema": {
+        "allOf": [
+          { "enum": ["a", "b", "c"] },
+          { "enum": ["d", "e", "f"] }
+        ]
+      },
+      "instance": "a",
+      "errors": [
+        {
+          "messageId": "boolean-schema-message",
+          "messageParams": {},
+          "instanceLocation": "#",
+          "schemaLocations": ["#/allOf/0/enum", "#/allOf/1/enum"]
+        }
+      ]
     }
   ]
 }