[9.x] Prevent triggering belongs to query if there are no relations to load

[pionl]

References issue #42493

• At this moment add the protection only for BelongsTo relation (can be added to Relation if more use cases are found)
• Prevents a query with empty whereIn value which reduces queries to DB.

[taylorotwell]

Thanks for your pull request to Laravel!

Unfortunately, I'm going to delay merging this code for now. To preserve our ability to adequately maintain the framework, we need to be very careful regarding the amount of code we include.

If possible, please consider releasing your code as a package so that the community can still take advantage of your contributions!

If you feel absolutely certain that this code corrects a bug in the framework, please "@" mention me in a follow-up comment with further explanation so that GitHub will send me a notification of your response.

[pionl]

Hi @taylorotwell, I truly believe this is a bug that bothers me from L5.4. Why would framework want to trigger a query on database that will return "nothing". This is a quite simple fix.

Of course I can make my "own" belongs to relation and use it, but I believe that hurts the quality of the framework that all the people like.

Here is a copy of explanation from issue. Thank you for your time.

• Laravel Version: 9.13.0
• PHP Version: 8.1.2

Description:

• While using belongsTo relations (with/load) there can be situations when there are no relations (nullable relations) to be loaded and query is "invalid". -> select `id`, `name`, `public_name` from `options` where 0 = 1 .
• This similar issue can be potentially found on other relations
• This bug is not noticeable if the results contains at least 1 value in the relation (if you have pagination, some pages can contain this error).

Steps To Reproduce:

1. Create a table with optional belongsTo relations
2. Build a query to get the results (all results should contain null)
3. Here a screenshot of a real queries

[pionl]

HI @taylorotwell, any second thoughts? Thank you

[pionl]

Hi @taylorotwell as 10.X version is ahead of us, could we reconsider fixing this bug? This will prevent sending unnecessary query. We could say this makes Laravel more cost efficient, and we all love that, right? :)

I'm happy to update it to 10.x.

Thank you for everything