Panic with uint8 column types

[muety]

Sorry for skipping the playground PR, but I think the below snippet should explain the issue well enough.

Example

package main

import (
	"gorm.io/driver/postgres"
	"gorm.io/gorm"
	"gorm.io/gorm/logger"
)

type Foo struct {
	ID     uint  `gorm:"primary_key"`
	Field1 uint8 `gorm:"not null; index:idx_1"`
}

func main() {
	db, err := gorm.Open(postgres.New(postgres.Config{
		DSN: "host=localhost port=5432 user=gorm_debug dbname=gorm_debug password=gorm_debug",
	}), &gorm.Config{
		Logger: logger.Default.LogMode(logger.Info),
	})
	if err != nil {
		panic(err)
	}

	if err := db.AutoMigrate(&Foo{}); err != nil {
		panic(err)
	}
}

Here's the output:

2022/04/03 18:00:11 /home/ferdinand/go/pkg/mod/gorm.io/driver/postgres@v1.3.3/migrator.go:145
[2.766ms] [rows:1] SELECT count(*) FROM information_schema.tables WHERE table_schema = CURRENT_SCHEMA() AND table_name = 'foos' AND table_type = 'BASE TABLE'

2022/04/03 18:00:11 /home/ferdinand/go/pkg/mod/gorm.io/driver/postgres@v1.3.3/migrator.go:20
[0.381ms] [rows:1] SELECT CURRENT_DATABASE()

2022/04/03 18:00:11 /home/ferdinand/go/pkg/mod/gorm.io/driver/postgres@v1.3.3/migrator.go:330
[9.333ms] [rows:-] SELECT c.column_name, c.is_nullable = 'YES', c.udt_name, c.character_maximum_length, c.numeric_precision, c.numeric_precision_radix, c.numeric_scale, c.datetime_precision, 8 * typlen, c.column_default, pd.description FROM information_schema.columns AS c JOIN pg_type AS pgt ON c.udt_name = pgt.typname LEFT JOIN pg_catalog.pg_description as pd ON pd.objsubid = c.ordinal_position AND pd.objoid = (SELECT oid FROM pg_catalog.pg_class WHERE relname = c.table_name AND relnamespace = (SELECT oid FROM pg_catalog.pg_namespace WHERE nspname = c.table_schema)) where table_catalog = 'gorm_debug' AND table_schema = CURRENT_SCHEMA() AND table_name = 'foos'

2022/04/03 18:00:11 /home/ferdinand/go/pkg/mod/gorm.io/driver/postgres@v1.3.3/migrator.go:461
[0.457ms] [rows:-] SELECT * FROM "foos" LIMIT 1

2022/04/03 18:00:11 /home/ferdinand/go/pkg/mod/gorm.io/driver/postgres@v1.3.3/migrator.go:400
[9.246ms] [rows:-] SELECT c.column_name, constraint_type FROM information_schema.table_constraints tc JOIN information_schema.constraint_column_usage AS ccu USING (constraint_schema, constraint_name) JOIN information_schema.columns AS c ON c.table_schema = tc.constraint_schema AND tc.table_name = c.table_name AND ccu.column_name = c.column_name WHERE constraint_type IN ('PRIMARY KEY', 'UNIQUE') AND c.table_catalog = 'gorm_debug' AND c.table_schema = CURRENT_SCHEMA() AND c.table_name = 'foos'

2022/04/03 18:00:11 /home/ferdinand/go/pkg/mod/gorm.io/driver/postgres@v1.3.3/migrator.go:430
[0.852ms] [rows:-] SELECT a.attname as column_name, format_type(a.atttypid, a.atttypmod) AS data_type
                FROM pg_attribute a JOIN pg_class b ON a.attrelid = b.relfilenode AND relnamespace = (SELECT oid FROM pg_catalog.pg_namespace WHERE nspname = CURRENT_SCHEMA())
                WHERE a.attnum > 0 -- hide internal columns
                AND NOT a.attisdropped -- hide deleted columns
                AND b.relname = 'foos'

2022/04/03 18:00:11 /home/ferdinand/go/pkg/mod/gorm.io/driver/postgres@v1.3.3/migrator.go:218
[5.948ms] [rows:0] SELECT description FROM pg_catalog.pg_description WHERE objsubid = (SELECT ordinal_position FROM information_schema.columns WHERE table_schema = CURRENT_SCHEMA() AND table_name = 'foos' AND column_name = 'id') AND objoid = (SELECT oid FROM pg_catalog.pg_class WHERE relname = 'foos' AND relnamespace = (SELECT oid FROM pg_catalog.pg_namespace WHERE nspname = CURRENT_SCHEMA()))

2022/04/03 18:00:11 /home/ferdinand/go/pkg/mod/gorm.io/driver/postgres@v1.3.3/migrator.go:20
[0.200ms] [rows:1] SELECT CURRENT_DATABASE()

2022/04/03 18:00:11 /home/ferdinand/go/pkg/mod/gorm.io/driver/postgres@v1.3.3/migrator.go:330
[5.446ms] [rows:-] SELECT c.column_name, c.is_nullable = 'YES', c.udt_name, c.character_maximum_length, c.numeric_precision, c.numeric_precision_radix, c.numeric_scale, c.datetime_precision, 8 * typlen, c.column_default, pd.description FROM information_schema.columns AS c JOIN pg_type AS pgt ON c.udt_name = pgt.typname LEFT JOIN pg_catalog.pg_description as pd ON pd.objsubid = c.ordinal_position AND pd.objoid = (SELECT oid FROM pg_catalog.pg_class WHERE relname = c.table_name AND relnamespace = (SELECT oid FROM pg_catalog.pg_namespace WHERE nspname = c.table_schema)) where table_catalog = 'gorm_debug' AND table_schema = CURRENT_SCHEMA() AND table_name = 'foos'

2022/04/03 18:00:11 /home/ferdinand/go/pkg/mod/gorm.io/driver/postgres@v1.3.3/migrator.go:461
[0.167ms] [rows:-] SELECT * FROM "foos" LIMIT 1

2022/04/03 18:00:11 /home/ferdinand/go/pkg/mod/gorm.io/driver/postgres@v1.3.3/migrator.go:400
[7.104ms] [rows:-] SELECT c.column_name, constraint_type FROM information_schema.table_constraints tc JOIN information_schema.constraint_column_usage AS ccu USING (constraint_schema, constraint_name) JOIN information_schema.columns AS c ON c.table_schema = tc.constraint_schema AND tc.table_name = c.table_name AND ccu.column_name = c.column_name WHERE constraint_type IN ('PRIMARY KEY', 'UNIQUE') AND c.table_catalog = 'gorm_debug' AND c.table_schema = CURRENT_SCHEMA() AND c.table_name = 'foos'

2022/04/03 18:00:11 /home/ferdinand/go/pkg/mod/gorm.io/driver/postgres@v1.3.3/migrator.go:430
[0.376ms] [rows:-] SELECT a.attname as column_name, format_type(a.atttypid, a.atttypmod) AS data_type
                FROM pg_attribute a JOIN pg_class b ON a.attrelid = b.relfilenode AND relnamespace = (SELECT oid FROM pg_catalog.pg_namespace WHERE nspname = CURRENT_SCHEMA())
                WHERE a.attnum > 0 -- hide internal columns
                AND NOT a.attisdropped -- hide deleted columns
                AND b.relname = 'foos'
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x20 pc=0x81bdb7]

goroutine 1 [running]:
database/sql.(*ColumnType).DatabaseTypeName(...)
        /opt/go/src/database/sql/sql.go:3172
gorm.io/gorm/migrator.ColumnType.DatabaseTypeName(...)
        /home/ferdinand/go/pkg/mod/gorm.io/gorm@v1.23.4/migrator/column_type.go:44
gorm.io/driver/postgres.Migrator.AlterColumn.func1.1(0xc0002aa680?)
        /home/ferdinand/go/pkg/mod/gorm.io/driver/postgres@v1.3.3/migrator.go:251 +0xf7
gorm.io/gorm.(*DB).Connection(0x865960?, 0xc0001cf360)
        /home/ferdinand/go/pkg/mod/gorm.io/gorm@v1.23.4/finisher_api.go:539 +0x102
gorm.io/driver/postgres.Migrator.AlterColumn.func1(0xc0003a4700)
        /home/ferdinand/go/pkg/mod/gorm.io/driver/postgres@v1.3.3/migrator.go:249 +0x26b
gorm.io/gorm/migrator.Migrator.RunWithValue({{0xc0?, 0xc00038cdb0?, {0x97e320?, 0xc00028ae40?}}}, {0x843460?, 0xc000298ae0}, 0xc0001cf7a0)
        /home/ferdinand/go/pkg/mod/gorm.io/gorm@v1.23.4/migrator/migrator.go:52 +0x13c
gorm.io/driver/postgres.Migrator.AlterColumn({{{0x0?, 0xc00038cdb0?, {0x97e320?, 0xc00028ae40?}}}}, {0x843460?, 0xc000298ae0?}, {0x83a1be?, 0x0?})
        /home/ferdinand/go/pkg/mod/gorm.io/driver/postgres@v1.3.3/migrator.go:237 +0xb1
gorm.io/gorm/migrator.Migrator.MigrateColumn({{0xcb?, 0xc00038cbd0?, {0x97e320?, 0xc00028ae40?}}}, {0x843460, 0xc000298ae0}, 0xc0002965a0, {0x97e458, 0xc0002abd40})
        /home/ferdinand/go/pkg/mod/gorm.io/gorm@v1.23.4/migrator/migrator.go:464 +0x689
gorm.io/driver/postgres.Migrator.MigrateColumn({{{0x0?, 0xc00038cbd0?, {0x97e320?, 0xc00028ae40?}}}}, {0x843460, 0xc000298ae0}, 0xc0002965a0, {0x97e458?, 0xc0002abd40?})
        /home/ferdinand/go/pkg/mod/gorm.io/driver/postgres@v1.3.3/migrator.go:205 +0x95
gorm.io/gorm/migrator.Migrator.AutoMigrate.func1(0xc0002bcc40)
        /home/ferdinand/go/pkg/mod/gorm.io/gorm@v1.23.4/migrator/migrator.go:120 +0x17b
gorm.io/gorm/migrator.Migrator.RunWithValue({{0x30?, 0xc00029b830?, {0x97e320?, 0xc00028ae40?}}}, {0x843460?, 0xc000298ae0}, 0xc0001cfe10)
        /home/ferdinand/go/pkg/mod/gorm.io/gorm@v1.23.4/migrator/migrator.go:52 +0x13c
gorm.io/gorm/migrator.Migrator.AutoMigrate({{0x0?, 0xc00029b830?, {0x97e320?, 0xc00028ae40?}}}, {0xc0002b6a20?, 0x0?, 0x0?})
        /home/ferdinand/go/pkg/mod/gorm.io/gorm@v1.23.4/migrator/migrator.go:101 +0x1ce
gorm.io/gorm.(*DB).AutoMigrate(0x97e168?, {0xc0002b6a20, 0x1, 0x1})
        /home/ferdinand/go/pkg/mod/gorm.io/gorm@v1.23.4/migrator.go:28 +0x43
main.main()
        /home/ferdinand/dev/gorm-bug/main.go:24 +0x1ba

Process finished with the exit code 2