fix(sql/where): fixes regression for /: [], now correctly generates (NULL) rathe…

…r than (), closes #3132, closes #3105

changelog.md

+# Next
+- [BUG] Fixed regression where `{$in: []}` would result in `IN ()` rather than `IN (NULL)` [#3105](https://github.com/sequelize/sequelize/issues/3105) [#3132](https://github.com/sequelize/sequelize/issues/3132)
+
 # 2.0.2
 - [BUG] Fixed regression with `DataTypes.ARRAY(DataTypes.STRING(length))` [#3106](https://github.com/sequelize/sequelize/issues/3106)
 - [BUG] Fixed regression where `.or([{key: value}, {key: value, key2: value}])` would result in 3 `A OR B OR C` rather than `A OR (B AND C)` [#3107](https://github.com/sequelize/sequelize/issues/3107)

lib/dialects/abstract/query-generator.js

@@ -1643,6 +1643,7 @@ module.exports = (function() {
         return this.handleSequelizeMethod(value);
       }
 
+      // Convert where: [] to $and if possible, else treat as literal/replacements
       if (key === undefined && Array.isArray(value)) {
         if (Utils.canTreatArrayAsAnd(value)) {
           key = '$and';
@@ -1701,15 +1702,32 @@ module.exports = (function() {
         })();
       }
 
+      // Do [] to $in/$notIn normalization
+      if (value && !fieldType || !fieldType instanceof DataTypes.ARRAY) {
+        if (Array.isArray(value)) {
+          value = {
+            $in: value
+          };
+        } else if (value.$not && Array.isArray(value.$not)) {
+          value.$notIn = value.$not;
+          delete value.$not;
+        }
+      }
+
       // Setup keys and comparators
       if (Array.isArray(value) && fieldType instanceof DataTypes.ARRAY) {
         value = this.escape(value, field);
-      } else if (value && (value.$in || Array.isArray(value) || (value.$not && Array.isArray(value.$not)) || value.$notIn)) {
+      } else if (value && (value.$in || value.$notIn)) {
         comparator = 'IN';
-        if (value.$not || value.$notIn) comparator = 'NOT IN';
-        value = '('+(value.$in || value.$not || value.$notIn || value).map(function (item) {
-          return self.escape(item);
-        }).join(', ')+')';
+        if (value.$notIn) comparator = 'NOT IN';
+
+        if ((value.$in || value.$notIn).length) {
+          value = '('+(value.$in || value.$notIn).map(function (item) {
+            return self.escape(item);
+          }).join(', ')+')';
+        } else {
+          value = '(NULL)';
+        }
       } else if (value && value.$any) {
         comparator = '= ANY';
         if (value.$any.$values) {

test/unit/sql/where.test.js

@@ -95,6 +95,12 @@ suite(Support.getTestDialectTeaser('SQL'), function() {
         default: '[equipment] IN (1, 3)'
       });
 
+      testsql('equipment', {
+        $in: []
+      }, {
+        default: '[equipment] IN (NULL)'
+      });
+
       testsql('muscles', {
         in: [2, 4]
       }, {
@@ -139,6 +145,14 @@ suite(Support.getTestDialectTeaser('SQL'), function() {
       });
     });
 
+    suite('$notIn', function () {
+      testsql('equipment', {
+        $notIn: []
+      }, {
+        default: '[equipment] NOT IN (NULL)'
+      });
+    });
+
     suite('$and/$or', function () {
       suite('$or', function () {
         testsql('email', {