[Bug]: Adding column to compressed table fails if NULL is used as constraint

[ikkala]

What type of bug is this?

Incorrect result, Unexpected error

What subsystems and features are affected?

Command processing, Compression

What happened?

Following error occur in case of the following statement:

ALTER TABLE table1 ADD COLUMN column1 jsonb NULL;

ERROR: cannot add column with constraints to a hypertable that has compression enabled

On the other hand, following works:
ALTER TABLE table1 ADD COLUMN column1 jsonb;

TimescaleDB version affected

2.8.1

PostgreSQL version used

13.9

What operating system did you use?

Docker image timescale/timescaledb-ha:pg13.9-ts2.8.1-p3

What installation method did you use?

Docker

What platform did you run on?

On prem/Self-hosted

Relevant log output and stack trace

No response

How can we reproduce the bug?

CREATE TABLE "table1" (
  "ts" timestamptz NOT NULL,
  "column0" bigint NULL
);
SELECT create_hypertable(
  'table1',
  'ts'
);

ALTER TABLE table1 SET (
  timescaledb.compress
);
SELECT add_compression_policy('table1', INTERVAL '1d');

-- The following fails:
ALTER TABLE table1 ADD COLUMN column1 jsonb NULL;

[fabriziomello]

Good catch @ikkala! Thanks for reporting, providing a fix for it!

[ikkala]

Thanks! Background, why this popped up in the first place: I use DBeaver sometimes to generate DDL for changes like the ones in this issue, and DBeaver by default put that dummy NULL there.