fix(query): handle undefined field on unique constraint error (#10016) (#10018)

lib/dialects/abstract/index.js

@@ -56,7 +56,8 @@ AbstractDialect.prototype.supports = {
     parser: false,
     concurrently: false,
     type: false,
-    using: true
+    using: true,
+    functionBased: false
   },
   joinTableDependent: true,
   groupedLimit: true,

lib/dialects/abstract/query.js

@@ -126,9 +126,9 @@ class AbstractQuery {
   }
 
   getUniqueConstraintErrorMessage(field) {
-    let message = field + ' must be unique';
+    let message = field ? field + ' must be unique' : 'Must be unique';
 
-    if (this.model) {
+    if (field && this.model) {
       for (const key of Object.keys(this.model.uniqueKeys)) {
         if (this.model.uniqueKeys[key].fields.indexOf(field.replace(/"/g, '')) >= 0) {
           if (this.model.uniqueKeys[key].msg) {

lib/dialects/postgres/index.js

@@ -38,7 +38,8 @@ PostgresDialect.prototype.supports = _.merge(_.cloneDeep(AbstractDialect.prototy
   index: {
     concurrently: true,
     using: 2,
-    where: true
+    where: true,
+    functionBased: true
   },
   inserts: {
     onConflictDoNothing: ' ON CONFLICT DO NOTHING'

lib/dialects/sqlite/index.js

@@ -28,7 +28,8 @@ SqliteDialect.prototype.supports = _.merge(_.cloneDeep(AbstractDialect.prototype
   },
   index: {
     using: false,
-    where: true
+    where: true,
+    functionBased: true
   },
   transactionOptions: {
     type: true

test/integration/model/create.test.js

@@ -998,6 +998,26 @@ describe(Support.getTestDialectTeaser('Model'), () => {
       });
     });
 
+    if (current.dialect.supports.index.functionBased) {
+      it("doesn't allow duplicated records with unique function based indexes", function () {
+        const User = this.sequelize.define('UserWithUniqueUsernameFunctionIndex', {
+          username: Sequelize.STRING,
+          email: {type: Sequelize.STRING, unique: true}
+        });
+
+        return User.sync({force: true}).then(() => {
+          const tableName = User.getTableName();
+          return this.sequelize.query('CREATE UNIQUE INDEX lower_case_username ON "' + tableName + '" ((lower(username)))');
+        }).then(() => {
+          return User.create({username: 'foo'});
+        }).then(() => {
+          return User.create({username: 'foo'});
+        }).catch(Sequelize.UniqueConstraintError, err => {
+          expect(err).to.be.ok;
+        });
+      });
+    }
+
     it('raises an error if created object breaks definition contraints', function() {
       const UserNull = this.sequelize.define('UserWithNonNullSmth', {
         username: { type: Sequelize.STRING, unique: true },