postgres: Inappropiate migration generated for 'default: null'

Issue type:

[x] bug report [ ] feature request [ ] documentation issue

Database system/driver:

[ ] cordova [ ] mongodb [ ] mssql [ ] mysql / mariadb [ ] oracle [x] postgres [ ] cockroachdb [ ] sqlite [ ] sqljs [ ] react-native [ ] expo

TypeORM version:

[ ] latest [ ] @next [x] 0.2.28

Steps to reproduce or a small repository showing the problem:

This issue appears very similar to https://github.com/typeorm/typeorm/issues/5509 but for postgres.

Minimal entity declaration:

import { Entity, Column, PrimaryGeneratedColumn } from "typeorm";

@Entity()
export class Foo {
  @PrimaryGeneratedColumn()
  id: number;

  @Column()
  requiredString: string;

  @Column({ type: "text", nullable: true })
  optionalString: string | null;

  @Column({ type: "text", nullable: true, default: null })
  optionalStringWithExplicitDefault: string | null;
}

Even after syncing the schema, generating a migration still results in the lines

// from `up` method
await queryRunner.query(`ALTER TABLE "foo" ALTER COLUMN "optionalstringwithexplicitdefault" SET DEFAULT null`);

// in `down` method
await queryRunner.query(`ALTER TABLE "foo" ALTER COLUMN "optionalstringwithexplicitdefault" DROP DEFAULT`);

Expected behavior: the migration should not include these lines.

[vegerot]

@brahn I have the same issue. Looking at https://github.com/typeorm/typeorm/issues/150#issuecomment-272158658 , it appears as a temporary workaround we can do

@Column({ type: "text", nullable: true, default: () => "NULL" })

Let me know if this works for you

[vegerot]

To be more specific, when you generate multiple new migrations, each time the case of null gets flipped.

For example, at first it will say

query: ALTER TABLE "air_refuels" ALTER COLUMN "missionId" SET DEFAULT null

then after I run that migration, and gen a new one, the next migration will say

query: ALTER TABLE "air_refuels" ALTER COLUMN "missionId" SET DEFAULT NULL

After you run the next migration, generating yet another migration produces

query: ALTER TABLE "air_refuels" ALTER COLUMN "missionId" SET DEFAULT null

I don’t think @brahn noticed this when writing the issue.

This certainly seems like a TypeORM bug. Please let me know what I can do to help resolve it