[12.x] Apply eager load constraints to oneOfMany inner subquery

[sadique-cws]

Title: [12.x] Apply eager load constraints to oneOfMany inner subquery

Compare: 12.x...sadique-cws:framework:fix/eager-load-one-of-many-subquery-constraints

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Fixes #59318.

Problem

When eager loading a latestOfMany / ofMany relationship with constraints (e.g. with(['lastPayment' => fn($q) => $q->where('store_id', 1)])), the constraints were only being applied to the outer query, not the inner subquery that determines which record is the "latest".

This caused the inner subquery to pick the wrong aggregate row (e.g. the latest payment across all stores), and then the outer filter would discard it—silently returning null.

Solution

In Eloquent\Builder::eagerLoadRelation(), we now snapshot the outer query's wheres and bindings before and after the user's constraint closure runs. If the relation is a one-of-many relation, we copy those newly added wheres directly into the inner oneOfManySubQuery.

This ensures the inner subquery correctly determines "latest" or "oldest" within the user's filtered dataset, matching the behavior that users expect when adding constraints to eager loads. All existing eloquent relation tests pass.

[taylorotwell]

I am closing this pull request because it lacks sufficient explanation, tests, or both. It is difficult for us to merge pull requests without these things because the change may introduce breaking changes to the framework.

Feel free to re-submit your change with a thorough explanation of the feature and tests - integration tests are preferred over unit tests. Please include it's benefit to end users; the reasons it does not break any existing features; how it makes building web applications easier, etc.

Thanks!