What does "rough consensus"[1] look like on this thread? How do we make a
decision and close it out?
Kirk suggested an idea, there’s been a couple days of feedback, so we can:
1) reject the proposal and commit to using final ‘everywhere'
2) accept the proposal and use final very sparingly
3) continue the discussion over e-mail
4) take other steps to come to a consensus like
have a meeting with a few folks who are passionate about the topic
Try both approaches. Pick one module and use final everywhere, and
pick another and use it sparingly and see which approach we like
Personally, I don’t see any “fundamental flaws"[1] with using final or removing
it.
Also, I might just be rushing the natural flow of conversation, so in that
case, sorry for being impatient.
1-https://doist.com/blog/decision-making-flat-organization/
<https://doist.com/blog/decision-making-flat-organization/>
> On Jun 18, 2019, at 2:48 PM, Jinmei Liao <jil...@pivotal.io> wrote:
>
> I agree with Murtuza, most finals on local variables and method parameters
> are just noise to me. I only use "final" on these two situations:
> 1. to declare public static constants of immutable types (e.g. String,
> Integer)
> 2. to prevent children from overriding a method.
>
> But thought I can't offer an example, I don't want to put out a blank
> statement saying that "final" on local variables are entirely unnecessary.
> There must be a case that it could be useful, so even if we come to a
> consensus that local variables should not have final on it, I don't think
> using a static analysis tool to get rid of all of them is a good idea.
>
> On Tue, Jun 18, 2019 at 11:14 AM Anthony Baker <aba...@pivotal.io> wrote:
>
>> I’ll offer this alternative: perhaps shorter method bodies obviate the
>> need for explicit final vars.
>>
>> Anthony
>>
>>
>>> On Jun 18, 2019, at 10:30 AM, Ernest Burghardt <eburgha...@pivotal.io>
>> wrote:
>>>
>>> +1 to auto-enforcement (if possible) post-consensus
>>>
>>> On Tue, Jun 18, 2019 at 8:33 AM Murtuza Boxwala <mboxw...@pivotal.io>
>> wrote:
>>>
>>>> final in Java does not guarantee immutability. It would be AWESOME if
>> it
>>>> did but all it guarantees is that the variable cannot be reassigned. In
>>>> most cases the variable points to an object’s location (memory
>> address), so
>>>> you can still call methods on it, e.g.
>>>>
>>>> final var = new Foo();
>>>> var.mutateState();
>>>>
>>>> final variables like these are in no way thread safe. To make objects
>>>> immutable, the objects themselves need to follow a pattern that
>> guarantees
>>>> that. Something like the ValueObject <
>>>> https://martinfowler.com/bliki/ValueObject.html> pattern.
>>>>
>>>> Mutability may well be the enemy, but I don’t think this is the
>> construct
>>>> that gets us much/if any closer.
>>>>
>>>> In local variables and parameters final feels like noise to me, and in
>>>> fact may make things more difficult to reason about, if we start
>> assuming
>>>> variables with final are thread safe.
>>>>
>>>> But I may be missing something. I am more curious to see how we come to
>>>> consensus on something like this, because the worst outcome from all
>> this
>>>> will be to have some folks actively adding final and some actively
>> removing
>>>> it, which will add noise to PRs and to the code. And once we reach
>>>> consensus, how do we enforce somethings like this? ./gradlew spA?
>>>>
>>>>> On Jun 17, 2019, at 8:55 PM, Jacob Barrett <jbarr...@pivotal.io>
>> wrote:
>>>>>
>>>>> I too am in camp final too. You could say `final boolean useFinal =
>>>> true`. For all the same reasons Bill stated below.
>>>>>
>>>>>> On Jun 17, 2019, at 5:33 PM, Bill Burcham <bburc...@pivotal.io>
>> wrote:
>>>>>>
>>>>>> The final keyword is not redundant—quite the opposite—it's extremely
>>>> valuable.
>>>>>>
>>>>>> Local variables are not, in general, final, unless you declare them as
>>>> such. That being the case, it is not redundant to declare local
>> variables
>>>> "final".
>>>>>>
>>>>>> What the compiler will do for you, is _if_ it can ensure that a local
>>>> variable (or method parameter) is never modified (after initialization)
>>>> then that variable is treated as "effectively final". Variables that are
>>>> explicitly declared final, or are determined to be "effectively final"
>> may
>>>> be referenced in lambdas. That's a nice thing.
>>>>>>
>>>>>> I would like to offer a counter-recommendation: final should be the
>>>> default everywhere for fields, for method parameters (on classes, not on
>>>> interfaces), and for local variables.
>>>>>>
>>>>>> Many benefits would accrue to us, should we adopt this default:
>>>>>>
>>>>>> 1. final fields must be initialized in a constructor and never mutated
>>>> again. This makes reasoning about those fields easier.
>>>>>> 2. classes that have all their fields final are immutable and hence
>>>> easier to reason about: they can be passed between threads, for
>> instance,
>>>> with no need to protect from races
>>>>>> 3. final method parameters can never be mutated, making them easier to
>>>> reason about
>>>>>> 4. final local variables can never be mutated, making them easier to
>>>> reason about
>>>>>>
>>>>>> When final is the rule, non-final is the exception. Another way of
>>>> saying that is that when final is the rule, mutability is the exception.
>>>> That is as it should be. Mutability is the enemy.
>>>>>>
>>>>>> I have turned on a couple IntelliJ settings that make this the default
>>>> for me. I encourage you to do the same:
>>>>>>
>>>>>> First there are these two "Code style issues" in the Java inspections:
>>>>>>
>>>>>> "Field may be 'final'"
>>>>>> "Local variable or parameter can be final"
>>>>>>
>>>>>>
>>>>>>
>>>>>> Then there is this setting will cause newly-defined variables created
>>>> via the "Extract variable" refactoring:
>>>>>>
>>>>>> If you select that check box (after selecting those inspections
>>>> settings above), it'll declare the newly-introduced variable "final" and
>>>> it'll remember the setting the next time you invoke "Extract variable"
>>>> refactoring
>>>>>>
>>>>>>
>>>>
>>>>
>>
>>
>
> --
> Cheers
>
> Jinmei
