'subErrorsAt' now only returns actual sub errors

Previously 'subErrorsAt' included the errors for the given path itself. However these can
already be determined via 'errorsAt'. This fixes some issues in which errors were
duplicated in the UI.

Closes #1684
Closes #1760

packages/core/src/reducers/core.ts

@@ -424,4 +424,4 @@ const getErrorsAt = (
 export const errorAt = (instancePath: string, schema: JsonSchema) =>
   getErrorsAt(instancePath, schema, path => path === instancePath);
 export const subErrorsAt = (instancePath: string, schema: JsonSchema) =>
-  getErrorsAt(instancePath, schema, path => path.startsWith(instancePath));
+  getErrorsAt(instancePath, schema, path => path.startsWith(instancePath + '.'));

packages/core/test/reducers/core.test.ts

@@ -1175,6 +1175,42 @@ test('subErrorsAt filters array inner', t => {
   t.deepEqual(filtered[0], state.errors[1]);
 });
 
+test('subErrorsAt only returning suberrors', t => {
+  const ajv = createAjv();
+  const schema: JsonSchema = {
+    type: 'object',
+    properties: {
+      numbers: {
+        title: 'Numbers',
+        type: 'array',
+        minItems: 1,
+        items: {
+          title: 'Type',
+          type: 'string',
+          enum: ['One', 'Two', 'Three']
+        },
+      }
+    }
+  };
+  const data: { numbers: string[] } = {
+    numbers: []
+  };
+  const v = ajv.compile(schema);
+  const errors = validate(v, data);
+
+  const state: JsonFormsCore = {
+    data,
+    schema,
+    uischema: undefined,
+    errors
+  };
+  const subErrors = subErrorsAt(
+    'numbers',
+    schema.properties.numbers.items as JsonSchema
+  )(state);
+  t.is(subErrors.length, 0);
+});
+
 test('subErrorsAt filters oneOf array inner', t => {
   const ajv = createAjv();
   const schema: JsonSchema = {