sql: unique without index constraint not validated if it's added with drop column in one statement

[chengxiong-ruan]

Describe the problem
if a UNIQUE WITHOUT INDEX constraint is added with a DROP COLUMN in one statement, the uniqueness is not vlidated.

To Reproduce

root@localhost:26257/defaultdb> create table t1 (a int, b int);
CREATE TABLE

root@localhost:26257/defaultdb> insert into t1 (a) values (1), (1);
INSERT 0 2

root@localhost:26257/defaultdb> alter table t1 drop column b, add constraint c1 unique
                             -> without index (a);
ALTER TABLE

root@localhost:26257/defaultdb> select * from t1;
  a
-----
  1
  1
(2 rows)

root@localhost:26257/defaultdb> show create table t1;
  table_name |                      create_statement
-------------+--------------------------------------------------------------
  t1         | CREATE TABLE public.t1 (
             |     a INT8 NULL,
             |     rowid INT8 NOT VISIBLE NOT NULL DEFAULT unique_rowid(),
             |     CONSTRAINT t1_pkey PRIMARY KEY (rowid ASC),
             |     CONSTRAINT c1 UNIQUE WITHOUT INDEX (a)
             | )

root@localhost:26257/defaultdb> insert into t1 values (1);
ERROR: duplicate key value violates unique constraint "c1"
SQLSTATE: 23505
DETAIL: Key (a)=(1) already exists.
CONSTRAINT: c1

Expected behavior
add unique constraint should fail...

Environment:

• CockroachDB version 23.1 and master

Jira issue: CRDB-25805

[chengxiong-ruan]

@Xiang-Gu feel free to close if this is expected which I don't think is the case.

[blathers-crl]

Hi @chengxiong-ruan, please add branch-* labels to identify which branch(es) this release-blocker affects.

_{🦉 Hoot! I am a Blathers, a bot for CockroachDB. My owner is dev-inf.}

[blathers-crl]

Hi @chengxiong-ruan, please add branch-* labels to identify which branch(es) this release-blocker affects.

_{🦉 Hoot! I am a Blathers, a bot for CockroachDB. My owner is dev-inf.}

[chengxiong-ruan]

Sorry, I touched the wrong ticket. This is still a GA blocker.

[ajwerner]

@Xiang-Gu was saying that we are missing the rule to wait for the source index to validate the constraint to be backfilled and validated.