fix(engine/dolphin): support enum in ALTER definition (#2680)

I got in a case similar to #1503. This PR will fix #1503.

I found one discrepancy between column definition between create table and alter definition. I fix it by defining a common sub function.

On generic engine update part, it was missing to create enum on alter table statement compared to create. I added an argument to the func createEnum to override previous definition when needed.

I added two tests to cover the two ALTER case MODIFY and CHANGE.

I only know very few part of the codebase so let me know If I need to change anything to make this merged.

Author: sapk

internal/endtoend/testdata/enum_alter_change/mysql/go/db.go

@@ -0,0 +1,2 @@
+-- name: ListAuthors :many
+select * from authors;

internal/endtoend/testdata/enum_alter_change/mysql/go/models.go

@@ -0,0 +1,9 @@
+-- similar to issue https://github.com/sqlc-dev/sqlc/issues/1503
+
+CREATE TABLE authors (
+  id   bigint primary key,
+  status enum("ok", "init") default "init" not null
+);
+
+-- remove this alter to see the change in models.go
+ALTER TABLE authors CHANGE status status enum('init', 'done', 'canceled', 'processing', 'waiting') default "init" not null;

internal/endtoend/testdata/enum_alter_change/mysql/go/query.sql.go

@@ -0,0 +1,13 @@
+{
+  "version": "1",
+  "packages": [
+    {
+      "name": "querytest",
+      "path": "go",
+      "schema": "schema.sql",
+      "queries": "query.sql",
+      "engine": "mysql",
+      "omit_unused_structs": true
+    }
+  ]
+}

internal/endtoend/testdata/enum_alter_change/mysql/query.sql

@@ -0,0 +1,2 @@
+-- name: ListAuthors :many
+select * from authors;

internal/endtoend/testdata/enum_alter_change/mysql/schema.sql

@@ -0,0 +1,9 @@
+-- similar to issue https://github.com/sqlc-dev/sqlc/issues/1503
+
+CREATE TABLE authors (
+  id   bigint primary key,
+  status enum("ok", "init") default "init" not null
+);
+
+-- remove this alter to see the change in models.go
+ALTER TABLE authors MODIFY status enum('init', 'done', 'canceled', 'processing', 'waiting') default "init" not null;

internal/endtoend/testdata/enum_alter_change/mysql/sqlc.json

@@ -0,0 +1,13 @@
+{
+  "version": "1",
+  "packages": [
+    {
+      "name": "querytest",
+      "path": "go",
+      "schema": "schema.sql",
+      "queries": "query.sql",
+      "engine": "mysql",
+      "omit_unused_structs": true
+    }
+  ]
+}