Fix : Type Mismatch in Polymorphic Relationships When Using PostgreSQL #54401

[bazan101]

I have implemented a fix for the PostgreSQL type mismatch issue in polymorphic relationships #54401 .

Summary of Changes:

1. Modified MorphOneOrMany.php:

   • Overridden addConstraints() to strictly cast the parent model's key to a string before
     adding the where clause. This ensures that the generated SQL uses strict string binding
     (e.g., '1' instead of 1), which is required by PostgreSQL when comparing against varchar
     columns.
   • Overridden addEagerConstraints() to:
     • Explicitly use whereIn instead of whereIntegerInRaw (or other variations), preventing
       Laravel from optimizing for integers when the foreign key column might be a string.
     • Strictly cast all parent keys to strings when binding to the query.

2. Updated Tests (DatabaseEloquentMorphTest.php):

   • Updated testMorphOneEagerConstraintsAreProperlyAdded and
     testMorphManyEagerConstraintsAreProperlyAdded to expect whereIn with string values (e.g.,
     ['1', '2']) instead of integers.
   • Updated helper methods (getOneRelation, getManyRelation, etc.) to expect where clauses
     with string values ('1') instead of integers.

Verification:

• Created a temporary test suite DatabaseEloquentMorphOneOrManyPostgresFixTest to confirm the
  bug (expectations failed with integers) and verify the fix (expectations met with strings).
• Ran the existing test suite DatabaseEloquentMorphTest.php and ensured all tests pass with the
  updated expectations.

This solution ensures compatibility with PostgreSQL's strict typing while maintaining
functionality for other databases (where string-to-int comparison is often implicit).

[shaedrich]

Can't you just do this?

Suggested change

	$this->getRelationQuery()->where($this->morphType, $this->morphClass);
	parent::addConstraints();
	$this->getRelationQuery()->where(
	$this->foreignKey, '=', (string) $this->getParentKey()
	);
	$this->getRelationQuery()->whereNotNull($this->foreignKey);
	$this->getRelationQuery()
	->where($this->morphType, $this->morphClass)
	->where($this->foreignKey, '=', (string) $this->getParentKey())
	->whereNotNull($this->foreignKey);

[bazan101]

yeah it is a better implementation but don't we want to to keep the parent::addConstraints(); line at the begining ?

[shaedrich]

we don't and we don't keep it