Prevent callback from being set twice. #7376
Conversation
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This will need a rebase. @jonleighton @tenderlove what do you think about this feature? |
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I've updated the branch with rails/master. Tests pass now. |
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Can you add a changelog entry as well, explaining the issue? |
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Done. Is that ok, or should I be more descriptive? |
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Looks fine I guess, although an example of the issue could be good. |
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Done. |
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Can you answer something? |
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This needs a rebase, But seems fine. |
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Done. |
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Come on! Is it fine, or it is not, or you are going in 2 weeks again say it needs a rebase? |
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@dmitriy-kiriyenko please be patient, we have lots of issues to review and give feedback. I'll review yours again later if anyone else does before me, it's in my todo list. Thanks for your work on that. |
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There was a problem hiding this comment.
Should this be OneTwoThreeSave?
When you add one callack in two separate `set_callback` calls - it is
only called once.
When you do it in one `set_callback` call - it is called twice.
This violates the principle of least astonishment for me. Duplicating
callback is usually an error. There is a correct and obvious way to do
anything without this "feature".
If you want to do
before_save :clear_balance, :calculate_tax, :clear_balance
or whatever, you should better do
before_save :carefully_calculate_tax
def carefully_calculate_tax
clear_balance
calculate_tax
clear_balance
end
And this even opens gates for some advanced refactorings, unlike the
first approach.
My assumptions are:
- Principle of least astonishment is violated, when callbacks are either
prevented from duplication, or not.
- Duplicating callbacks is usually an error. When it is intentional -
it's a smell of a bad design and can be approached without abusing
this "feature".
My suggestion is: do not allow duplicating callbacks in one callback
call, like it is not allowed in separate callbacks call.
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Done. |
…n-same-statement Prevent callback from being set twice. Conflicts: activesupport/CHANGELOG.md
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Thanks and sorry for the delay. As @carlosantoniodasilva said, we have a lot of things to do and sometimes things can take a little longer than expected. |
When you add one callack in two separate
set_callbackcalls - it is only called once.When you do it in one
set_callbackcall - it is called twice.This violates the principle of least astonishment for me. Duplicating callback is usually an error. There is a correct and obvious way to do anything without this "feature".
If you want to do:
or whatever, you should better do:
And this even opens gates for some advanced refactorings, unlike the first approach.
My assumptions are:
My suggestion is: do not allow duplicating callbacks in one callback call, like it is not allowed in separate callbacks call.
P.S. It's currently one test on railties failing in master and so in this branch also. It's not me!