feat: invalidDefaults option to warn when defaults are ignored, fixes #…

…957

README.md

@@ -798,13 +798,14 @@ console.log(validate(data)); // true
 console.log(data); // [ 1, "foo" ]
 ```
 
-`default` keywords in other cases are ignored:
+`default` keywords in other cases are invalid:
 
 - not in `properties` or `items` subschemas
 - in schemas inside `anyOf`, `oneOf` and `not` (see [#42](https://github.com/epoberezkin/ajv/issues/42))
 - in `if` subschema of `switch` keyword
 - in schemas generated by custom macro keywords
 
+The [`invalidDefaults` option](#options) customizes Ajv's behavior for invalid defaults (`false` ignores invalid defaults, `true` raises an error, and `"log"` outputs a warning).
 
 ## Coercing data types
 
@@ -1070,6 +1071,7 @@ Defaults:
   removeAdditional: false,
   useDefaults:      false,
   coerceTypes:      false,
+  invalidDefaults:  false,
   // asynchronous validation options:
   transpile:        undefined, // requires ajv-async package
   // advanced options:
@@ -1151,6 +1153,10 @@ Defaults:
   - `false` (default) - no type coercion.
   - `true` - coerce scalar data types.
   - `"array"` - in addition to coercions between scalar types, coerce scalar data to an array with one element and vice versa (as required by the schema).
+- _invalidDefaults_: specify behavior for invalid `default` keywords in schemas. Option values:
+  - `false` (default) - ignore invalid defaults
+  - `true` - if an invalid default is present, throw an error
+  - `"log"` - if an invalid default is present, log warning
 
 
 ##### Asynchronous validation options

lib/ajv.d.ts

@@ -180,6 +180,7 @@ declare namespace ajv {
     removeAdditional?: boolean | 'all' | 'failing';
     useDefaults?: boolean | 'shared';
     coerceTypes?: boolean | 'array';
+    invalidDefaults?: boolean | 'log';
     async?: boolean | string;
     transpile?: string | ((code: string) => string);
     meta?: boolean | object;

lib/ajv.js

@@ -39,7 +39,7 @@ Ajv.$dataMetaSchema = $dataMetaSchema;
 
 var META_SCHEMA_ID = 'http://json-schema.org/draft-07/schema';
 
-var META_IGNORE_OPTIONS = [ 'removeAdditional', 'useDefaults', 'coerceTypes' ];
+var META_IGNORE_OPTIONS = [ 'removeAdditional', 'useDefaults', 'coerceTypes', 'invalidDefaults' ];
 var META_SUPPORT_DATA = ['/properties'];
 
 /**

lib/dot/defaults.def

@@ -1,15 +1,25 @@
 {{## def.assignDefault:
-  if ({{=$passData}} === undefined
-    {{? it.opts.useDefaults == 'empty' }}
-      || {{=$passData}} === null
-      || {{=$passData}} === ''
+  {{? it.compositeRule }}
+    {{? it.opts.invalidDefaults }}
+      {{? it.opts.invalidDefaults === 'log' }}
+        {{ it.logger.warn('default is ignored for: ' + $passData); }}
+      {{??}}
+        {{ throw new Error('default is ignored for: ' + $passData); }}
+      {{?}}
     {{?}}
-  )
-    {{=$passData}} = {{? it.opts.useDefaults == 'shared' }}
-                       {{= it.useDefault($sch.default) }}
-                     {{??}}
-                       {{= JSON.stringify($sch.default) }}
-                     {{?}};
+  {{??}}
+    if ({{=$passData}} === undefined
+      {{? it.opts.useDefaults == 'empty' }}
+        || {{=$passData}} === null
+        || {{=$passData}} === ''
+      {{?}}
+    )
+      {{=$passData}} = {{? it.opts.useDefaults == 'shared' }}
+                         {{= it.useDefault($sch.default) }}
+                       {{??}}
+                         {{= JSON.stringify($sch.default) }}
+                       {{?}};
+  {{?}}
 #}}
 
 

lib/dot/validate.jst

@@ -72,6 +72,13 @@
 
     it.dataPathArr = [undefined];
   }}
+  {{? it.opts.invalidDefaults && it.schema.default !== undefined }}
+    {{? it.opts.invalidDefaults === 'log' }}
+      {{ it.logger.warn('default is ignored in the schema root'); }}
+    {{??}}
+      {{ throw new Error('default is ignored in the schema root'); }}
+    {{?}}
+  {{?}}
 
   var vErrors = null; {{ /* don't edit, used in replace */ }}
   var errors = 0;     {{ /* don't edit, used in replace */ }}
@@ -177,7 +184,7 @@
       {{? $rulesGroup.type }}
         if ({{= it.util.checkDataType($rulesGroup.type, $data) }}) {
       {{?}}
-        {{? it.opts.useDefaults && !it.compositeRule }}
+        {{? it.opts.useDefaults }}
           {{? $rulesGroup.type == 'object' && it.schema.properties }}
             {{# def.defaultProperties }}
           {{?? $rulesGroup.type == 'array' && Array.isArray(it.schema.items) }}

spec/options/useDefaults.spec.js

@@ -2,7 +2,7 @@
 
 var Ajv = require('../ajv');
 var getAjvInstances = require('../ajv_instances');
-require('../chai').should();
+var should = require('../chai').should();
 
 
 describe('useDefaults options', function() {
@@ -220,4 +220,90 @@ describe('useDefaults options', function() {
       });
     });
   });
+
+  describe('invalidDefaults option', function() {
+    it('should throw an error given an invalid default in the schema root when invalidDefaults is true', function() {
+      var ajv = new Ajv({useDefaults: true, invalidDefaults: true});
+      var schema = {
+        default: 5,
+        properties: {}
+      };
+      should.throw(function() { ajv.compile(schema); });
+    });
+
+    it('should throw an error given an invalid default in oneOf when invalidDefaults is true', function() {
+      var ajv = new Ajv({useDefaults: true, invalidDefaults: true});
+      var schema = {
+        oneOf: [
+          { enum: ['foo', 'bar'] },
+          {
+            properties: {
+              foo: {
+                default: true
+              }
+            }
+          }
+        ]
+      };
+      should.throw(function() { ajv.compile(schema); });
+    });
+
+    it('should log a warning given an invalid default in the schema root when invalidDefaults is "log"', function() {
+      var warnArg = null;
+      var ajv = new Ajv({
+        useDefaults: true,
+        invalidDefaults: 'log',
+        logger: {
+          log: function() {
+            throw new Error('should not be called');
+          },
+          warn: function(warning) {
+            warnArg = warning;
+          },
+          error: function() {
+            throw new Error('should not be called');
+          }
+        }
+      });
+      var schema = {
+        default: 5,
+        properties: {}
+      };
+      ajv.compile(schema);
+      should.equal(warnArg, 'default is ignored in the schema root');
+    });
+
+    it('should log a warning given an invalid default in oneOf when invalidDefaults is "log"', function() {
+      var warnArg = null;
+      var ajv = new Ajv({
+        useDefaults: true,
+        invalidDefaults: 'log',
+        logger: {
+          log: function() {
+            throw new Error('should not be called');
+          },
+          warn: function(warning) {
+            warnArg = warning;
+          },
+          error: function() {
+            throw new Error('should not be called');
+          }
+        }
+      });
+      var schema = {
+        oneOf: [
+          { enum: ['foo', 'bar'] },
+          {
+            properties: {
+              foo: {
+                default: true
+              }
+            }
+          }
+        ]
+      };
+      ajv.compile(schema);
+      should.equal(warnArg, 'default is ignored for: data.foo');
+    });
+  });
 });