bug: postgres driver tries to insert slices and arrays as records, and fails (reproduction included)

[sleddev]

GORM Playground Link

https://github.com/go-gorm/playground/pull/668

Description

Explain your user case and expected results

When inserting go arrays or slices in a GORM model, the generated SQL uses them as records, so the insert fails.

For example:

type Test struct {
    Data []float64 `gorm:"type:float8[]"`
}

test := Test{Data: []float64{8, 4, 2, 1, 0.5}}
DB.Create(&test)

gives the SQL:

INSERT INTO "tests" ("data") VALUES ((8,4,2,1,0.5))

And I get the error ERROR: column "data" is of type double precision[] but expression is of type record (SQLSTATE 42804)

Instead, the SQL should be:

INSERT INTO "tests" ("data") VALUES ('{8,4,2,1,0.5}')

or

INSERT INTO "tests" ("data") VALUES (ARRAY [8,4,2,1,0.5])

If I use pgx directly, and do:

conn, err := pgx.Connect(...)

arr := []float64{8, 4, 2, 1, 0.5}
_, err = conn.Exec(context.Background(), "INSERT INTO tests (data) VALUES($1)", arr)

It works as expected, generating SQL with the '{...}' syntax

[carlcris]

i encountered the same issue, @sleddev did you manage to sort it out?

[sleddev]

@carlcris I ended up making type aliases, and implementing my own Scan and Value functions on those types.

Here's my current implementation: https://gist.github.com/sleddev/17ddd0e5f2a037ecf7bb6527367cb916

There may be edge cases I didn't account for, but from my testing and usage works nicely.

To use it, just swap []float64 to pg.Float8Array in your model