schemadiff: Online DDL support, declarative based (#16462)

Signed-off-by: Shlomi Noach <[email protected]>

go/test/endtoend/onlineddl/vrepl_suite/onlineddl_vrepl_suite_test.go

@@ -65,6 +65,7 @@ const (
 	testFilterEnvVar = "ONLINEDDL_SUITE_TEST_FILTER"
 )
 
+// Use $VREPL_SUITE_TEST_FILTER environment variable to filter tests by name.
 func TestMain(m *testing.M) {
 	defer cluster.PanicHandler(nil)
 	flag.Parse()

go/test/endtoend/onlineddl/vrepl_suite/testdata/fail-different-pk-new-pk-column/expect_failure

@@ -1 +1 @@
-Found no possible
+found no possible

go/test/endtoend/onlineddl/vrepl_suite/testdata/fail-drop-pk/expect_failure

@@ -1 +1 @@
-Found no possible
+found no possible

go/test/endtoend/onlineddl/vrepl_suite/testdata/fail-float-unique-key/create.sql

@@ -1,6 +1,6 @@
 drop table if exists onlineddl_test;
 create table onlineddl_test (
-  f float,
+  f float not null,
   i int not null,
   ts timestamp default current_timestamp,
   dt datetime,

go/test/endtoend/onlineddl/vrepl_suite/testdata/fail-float-unique-key/expect_failure

@@ -1 +1 @@
-Found no possible
+found no possible

go/test/endtoend/onlineddl/vrepl_suite/testdata/fail-no-unique-key/expect_failure

@@ -1 +1 @@
-Found no possible
+found no possible

go/test/endtoend/onlineddl/vrepl_suite/testdata/fail-nullable-unique-key/alter

@@ -0,0 +1 @@
+add column v varchar(32)

go/test/endtoend/onlineddl/vrepl_suite/testdata/fail-nullable-unique-key/create.sql

@@ -0,0 +1,11 @@
+drop table if exists onlineddl_test;
+create table onlineddl_test (
+  id int,
+  i int not null,
+  ts timestamp default current_timestamp,
+  dt datetime,
+  key i_idx(i),
+  unique key id_uidx(id)
+) auto_increment=1;
+
+drop event if exists onlineddl_test;

go/test/endtoend/onlineddl/vrepl_suite/testdata/fail-nullable-unique-key/expect_failure

@@ -0,0 +1 @@
+found no possible

go/vt/schemadiff/capability.go

@@ -61,18 +61,6 @@ func alterOptionCapableOfInstantDDL(alterOption sqlparser.AlterOption, createTab
 		}
 	}
 
-	isGeneratedColumn := func(col *sqlparser.ColumnDefinition) (bool, sqlparser.ColumnStorage) {
-		if col == nil {
-			return false, 0
-		}
-		if col.Type.Options == nil {
-			return false, 0
-		}
-		if col.Type.Options.As == nil {
-			return false, 0
-		}
-		return true, col.Type.Options.Storage
-	}
 	colStringStrippedDown := func(col *sqlparser.ColumnDefinition, stripEnum bool) string {
 		strippedCol := sqlparser.Clone(col)
 		// strip `default`
@@ -153,7 +141,7 @@ func alterOptionCapableOfInstantDDL(alterOption sqlparser.AlterOption, createTab
 			return false, nil
 		}
 		for _, column := range opt.Columns {
-			if isGenerated, storage := isGeneratedColumn(column); isGenerated {
+			if isGenerated, storage := IsGeneratedColumn(column); isGenerated {
 				if storage == sqlparser.StoredStorage {
 					// Adding a generated "STORED" column is unsupported
 					return false, nil
@@ -188,7 +176,7 @@ func alterOptionCapableOfInstantDDL(alterOption sqlparser.AlterOption, createTab
 			// not supported if the column is part of an index
 			return false, nil
 		}
-		if isGenerated, _ := isGeneratedColumn(col); isGenerated {
+		if isGenerated, _ := IsGeneratedColumn(col); isGenerated {
 			// supported by all 8.0 versions
 			// Note: according to the docs dropping a STORED generated column is not INSTANT-able,
 			// but in practice this is supported. This is why we don't test for STORED here, like