Issue description

Crash when using Repository.save with a column of type 'time', array: true when switching from null to a value, in PostgreSQL

Expected Behavior

Update should occur without error (this was fine in 0.3.23).

Actual Behavior

When using Repository.save on an entity with a column of type time, nullable: true, array: true in PostgreSQL, with the following scenario:

• Entity is fetched using query builder
• entity.columnWithTypeTime value was previously null
• entity.columnWithTypeTime = ['12:00']
• repository.save(entity) <- this crashes

Note that crash does not happen when this column is not updated, so I suppose this relates to the "diff" process during .save to determine which columns should figure in the UPDATE request.

TypeError: Cannot read properties of null (reading 'map')
     at /app/src/persistence/SubjectChangedColumnsComputer.ts:110:49
     at Array.forEach (<anonymous>)
     at SubjectChangedColumnsComputer.computeDiffColumns (/app/src/persistence/SubjectChangedColumnsComputer.ts:37:34)
     at /app/src/persistence/SubjectChangedColumnsComputer.ts:21:18
     at Array.forEach (<anonymous>)
     at SubjectChangedColumnsComputer.compute (/app/src/persistence/SubjectChangedColumnsComputer.ts:20:18)
     at SubjectExecutor.recompute (/app/src/persistence/SubjectExecutor.ts:209:45)
     at new SubjectExecutor (/app/src/persistence/SubjectExecutor.ts:91:14)
     at /app/src/persistence/EntityPersistExecutor.ts:146:28
     at processTicksAndRejections (node:internal/process/task_queues:105:5)
     at async Promise.all (index 0)
     at EntityPersistExecutor.execute (/app/src/persistence/EntityPersistExecutor.ts:72:31)

Steps to reproduce

Create an entity with a time array column (this might happen with other array types, but I haven't tested yet).

@Entity('schools', { schema: 'public' })
export class School {
  @PrimaryGeneratedColumn({ type: 'integer', name: 'id' })
  id: number;

  @Column('time without time zone', { nullable: true, name: 'opening_monday', array: true })
  opening_monday: [string, string] | null;
}

Then write the following scenario:

• Entity is fetched using query builder

const school = await connection.getRepository(School).findOne({});

• entity.columnWithTypeTime value was previously null

require('assert').deepEqual(school.opening_monday, null);

• Write a value

school.opening_monday = ['12:00', '14:00'];

• Save

await connection.getRepository(School).save(school);

My Environment

TypeORM version 0.3.24
Node.js 22.16
TypeScript 5.7.2
Alpine Linux 3.21
PostgreSQL 16

Additional Context

No response

Relevant Database Driver(s)

• aurora-mysql
• aurora-postgres
• better-sqlite3
• cockroachdb
• cordova
• expo
• mongodb
• mysql
• nativescript
• oracle
• postgres
• react-native
• sap
• spanner
• sqlite
• sqlite-abstract
• sqljs
• sqlserver

Are you willing to resolve this issue by submitting a Pull Request?

Yes, I have the time, but I don't know how to start. I would need guidance.