Break up v5 table ALTERs for SQLite

Combining all operations into a single query was causing problems in
SQLite. This fixes that by breaking them up into separate queries. It
also moves one column length change to only run on MySQL, since SQLite
doesn't need it.

migrations/v5.go

@@ -20,30 +20,30 @@ func oauthSlack(db *datastore) error {
 					Column(
 						"provider",
 						wf_db.ColumnTypeVarChar,
-						wf_db.OptionalInt{Set: true, Value: 24,})).
+						wf_db.OptionalInt{Set: true, Value: 24})),
+			dialect.
+				AlterTable("oauth_client_states").
 				AddColumn(dialect.
 					Column(
 						"client_id",
 						wf_db.ColumnTypeVarChar,
-						wf_db.OptionalInt{Set: true, Value: 128,})),
+						wf_db.OptionalInt{Set: true, Value: 128})),
 			dialect.
 				AlterTable("oauth_users").
-				ChangeColumn("remote_user_id",
-					dialect.
-						Column(
-							"remote_user_id",
-							wf_db.ColumnTypeVarChar,
-							wf_db.OptionalInt{Set: true, Value: 128,})).
 				AddColumn(dialect.
 					Column(
 						"provider",
 						wf_db.ColumnTypeVarChar,
-						wf_db.OptionalInt{Set: true, Value: 24,})).
+						wf_db.OptionalInt{Set: true, Value: 24})),
+			dialect.
+				AlterTable("oauth_users").
 				AddColumn(dialect.
 					Column(
 						"client_id",
 						wf_db.ColumnTypeVarChar,
-						wf_db.OptionalInt{Set: true, Value: 128,})).
+						wf_db.OptionalInt{Set: true, Value: 128})),
+			dialect.
+				AlterTable("oauth_users").
 				AddColumn(dialect.
 					Column(
 						"access_token",
@@ -51,6 +51,18 @@ func oauthSlack(db *datastore) error {
 						wf_db.OptionalInt{Set: true, Value: 512,})),
 			dialect.CreateUniqueIndex("oauth_users", "oauth_users", "user_id", "provider", "client_id"),
 		}
+
+		if dialect != wf_db.DialectSQLite {
+			// This updates the length of the `remote_user_id` column. It isn't needed for SQLite databases.
+			builders = append(builders, dialect.
+				AlterTable("oauth_users").
+				ChangeColumn("remote_user_id",
+					dialect.
+						Column(
+							"remote_user_id",
+							wf_db.ColumnTypeVarChar,
+							wf_db.OptionalInt{Set: true, Value: 128})))
+		}
 		for _, builder := range builders {
 			query, err := builder.ToSQL()
 			if err != nil {