Postgres: AutoMigrate re-migrates everytime for some types

[moolitayer]

GORM Playground Link

go-gorm/playground#646

Description

Every time we run AutoMigrage we get re-migration for certain specification of types:

# Types
type:character varying
type:timestamp with time zone
type:varchar[]

A workaround is to specify the types in a different way (see reproduction) but the required types seems sphoradic.
Not sure why, but the issue did not force migration before we upgraded GORM and the Postgres driver.

See the attached reproduction for details.

[moolitayer]

@jinzhu PTAL, I haven't been able to get to the root cause of this issue. Does this report make sense? Is there a way as a user of GORM to overcome the bug?

[aliyoge]

I have encountered the same issue, and each time it requires a conversion from character varying to varchar(32).

[PerryProjects]

I have encountered the same issue. Whenever AutoMigrate runs on a model that includes a varchar[] column, it keeps generating a new ALTER TABLE statement on every run.

There must be a better solution than just using character varying[].

Using text[] works fine, but only if you don’t need to specify a maximum length for the array elements.

Is there any solution to fix that?

[DasJott]

There's a pull request for this issue.