bulkio: database with user defined schema not cleaned up properly on restore fail

[RichardJCai]

Reproduction:

func TestRestoreTypeDescriptorsRollBack(t *testing.T) {
	defer leaktest.AfterTest(t)()
	defer log.Scope(t).Close(t)

	_, tc, sqlDB, _, cleanupFn := BackupRestoreTestSetup(t, singleNode, 0, InitManualReplication)
	defer cleanupFn()

	for _, server := range tc.Servers {
		registry := server.JobRegistry().(*jobs.Registry)
		registry.TestingResumerCreationKnobs = map[jobspb.Type]func(raw jobs.Resumer) jobs.Resumer{
			jobspb.TypeRestore: func(raw jobs.Resumer) jobs.Resumer {
				r := raw.(*restoreResumer)
				r.testingKnobs.beforePublishingDescriptors = func() error {
					return errors.New("boom")
				}
				return r
			},
		}
	}

	sqlDB.Exec(t, `
CREATE DATABASE db;
CREATE SCHEMA db.s; // THIS LINE WAS ADDED
CREATE TYPE db.typ AS ENUM();
CREATE TABLE db.table (k INT PRIMARY KEY, v db.typ);
`)

	// Back up the database, drop it, and restore into it.
	sqlDB.Exec(t, `BACKUP DATABASE db TO 'nodelocal://0/test/1'`)
	sqlDB.Exec(t, `DROP DATABASE db`)
	sqlDB.ExpectErr(t, "boom", `RESTORE DATABASE db FROM 'nodelocal://0/test/1'`)
	sqlDB.CheckQueryResults(t, `SELECT count(*) FROM system.namespace WHERE name = 'typ'`, [][]string{{"0"}})

	// Back up database with user defined schema.
	sqlDB.Exec(t, `
CREATE DATABASE db;
CREATE SCHEMA db.s;
CREATE TYPE db.s.typ AS ENUM();
CREATE TABLE db.s.table (k INT PRIMARY KEY, v db.s.typ);
`)

	// Back up the database, drop it, and restore into it.
	sqlDB.Exec(t, `BACKUP DATABASE db TO 'nodelocal://0/test/2'`)
	sqlDB.Exec(t, `DROP DATABASE db`)
	sqlDB.ExpectErr(t, "boom", `RESTORE DATABASE db FROM 'nodelocal://0/test/2'`)
	sqlDB.CheckQueryResults(t, `SELECT count(*) FROM system.namespace WHERE name = 'typ'`, [][]string{{"0"}})
}

modified the test in backup_test.go

See the comment // THIS LINE WAS ADDED to see the diff between now and master.

If the database has an UDS, the descriptor is not deleted properly.
We run into the error pq: failed to resolve targets specified in the BACKUP stmt: duplicate database name: "db" used for ID 59 and 64

During the second BACKUP, the descriptors seem to still contain the descriptor for the original "db" with ID 59.

[blathers-crl]

cc @cockroachdb/bulk-io

[RichardJCai]

@adityamaru before you start working on this I think I have a fix for this already.

It's fixed as part of this commit: aaab40f
in #72000