Port #6204 to v4 (fix #6203) (#6421)

changelog.md

@@ -37,6 +37,7 @@
 - [FIXED] Generate correct SQL for JSON attributes with quote.
 [#6406](https://github.com/sequelize/sequelize/issues/6406)
 - [FIXED] Nested query return correct result when quoteIdentifiers is false. (Postgres) [#6363](https://github.com/sequelize/sequelize/issues/6363)
+- [FIXED] Fixed an issue where changing multiple ENUM columns in PostgreSQL could break. [#6203] (https://github.com/sequelize/sequelize/issues/6203)
 
 ## BC breaks:
 - Range type bounds now default to [postgres default](https://www.postgresql.org/docs/9.5/static/rangetypes.html#RANGETYPES-CONSTRUCT) `[)` (inclusive, exclusive), previously was `()` (exclusive, exclusive)

lib/dialects/postgres/query-generator.js

@@ -216,7 +216,7 @@ const QueryGenerator = {
       }
 
       if (attributes[attributeName].match(/^ENUM\(/)) {
-        query = this.pgEnum(tableName, attributeName, attributes[attributeName]) + query;
+        attrSql += this.pgEnum(tableName, attributeName, attributes[attributeName]);
         definition = definition.replace(/^ENUM\(.+\)/, this.quoteIdentifier('enum_' + tableName + '_' + attributeName));
         definition += ' USING (' + this.quoteIdentifier(attributeName) + '::' + this.quoteIdentifier(definition) + ')';
       }

test/unit/dialects/postgres/query-generator.test.js

@@ -201,6 +201,16 @@ if (dialect.match(/^postgres/)) {
         }
       ],
 
+      changeColumnQuery: [
+        {
+          arguments: ['myTable', {
+            col_1: "ENUM('value 1', 'value 2') NOT NULL",
+            col_2: "ENUM('value 3', 'value 4') NOT NULL"
+          }],
+          expectation: 'ALTER TABLE "myTable" ALTER COLUMN "col_1" SET NOT NULL;ALTER TABLE "myTable" ALTER COLUMN "col_1" DROP DEFAULT;CREATE TYPE "public"."enum_myTable_col_1" AS ENUM(\'value 1\', \'value 2\');ALTER TABLE "myTable" ALTER COLUMN "col_1" TYPE "public"."enum_myTable_col_1" USING ("col_1"::"public.enum_myTable_col_1");ALTER TABLE "myTable" ALTER COLUMN "col_2" SET NOT NULL;ALTER TABLE "myTable" ALTER COLUMN "col_2" DROP DEFAULT;CREATE TYPE "public"."enum_myTable_col_2" AS ENUM(\'value 3\', \'value 4\');ALTER TABLE "myTable" ALTER COLUMN "col_2" TYPE "public"."enum_myTable_col_2" USING ("col_2"::"public.enum_myTable_col_2");'
+        }
+      ],
+
       selectQuery: [
         {
           arguments: ['myTable'],