NotBlank validator should not invalidate null values #27876

Taluu · 2018-07-06T11:40:32Z

Description
In most validators, there's a failsafe mecanism that prevent the validator from validating if it's a null value, as there's a validator for that (NotNull). I think NotBlank shouldn't bother on null values, especially as NotBlank and NotNull are used together to prevent null values too.

Not really a feature request, but not really a bug too... more like a RFC but for all versions. But I guess this would be a BC break though. :/ So maybe add a deprecated on the validator if it's a null value or something, and remove the null invalidation from the NotBlank on 5.0 ?

Currently, we need to reimplement the validator just to skip null values...

Possible Solution
Either deprecate the validation on null value in NotBlank, or do as in most validators, (if null value, then skip). But as I mentionned, this would probably be a bc break.

The text was updated successfully, but these errors were encountered:

stof · 2018-07-06T14:46:24Z

That would be a huge BC break.
And due to the form component setting properties to null when submitting an empty field, it might even be confusing to change the behavior of NotBlank. So I'm not sure it is worth it.

theofidry · 2018-07-08T09:01:49Z

Maybe we could add a NullOrNotBlank and potentially rename NotBlank to NotNullNotBlank. I'm not too happy with the names but IMO it's the original name that is messed up and we can't change it without BC breaks.

On a side note, I witnessed at least 10 Symfony projects where they declared a NotBlank ignoring null values, so I also strongly feel there is an issue here.

ostrolucky · 2018-07-08T11:22:27Z

especially as NotBlank and NotNull are used together to prevent null values too.

Can you provide a source for this? We always use just NotBlank. Usage for NotNull is really rare in projects I've seen.

rename NotBlank to NotNullNotBlank

How is "not blank" value ever null value? Blank includes null.

I witnessed at least 10 Symfony projects where they declared a NotBlank ignoring null values,

For what use case?

theofidry · 2018-07-08T11:52:23Z

@ostrolucky because there is a need to check for non null empty values. null is often given either as "reset" or "not provided" value.

You can always argue that a form (for an API or not) - and I agree on paper. But in practice for a lot of front-ends omitting non provided fields as opposed to sending null requires too much work for what it's worth, hence this need in the back-end.

ostrolucky · 2018-07-08T14:46:41Z

If you have a text type field in your form and don't type anything there, it's transformed to null. If you omit that field completely, it's again null. There is no difference. This kind of problem is meant to be solved with validation groups.

theofidry · 2018-07-08T15:20:35Z

@ostrolucky I don't really see how that invalidates the points above tbh

xabbuh · 2018-07-08T18:46:24Z

If I don't misunderstand the proposal that would pretty much the same as having the Length constraint with min set to 1, isn't it?

theofidry · 2018-07-08T18:59:10Z

Provides the value is a string but NotBlank also works on other types

…

On Sun 8 Jul 2018 at 20:46, Christian Flothmann ***@***.***> wrote: If I don't misunderstand the proposal that would pretty much the same as having the Length constraint with min set to 1, isn't it? — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#27876 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AE76gXwgY2hK-pKQnpLUU9zMM-Y0c-0Pks5uElOMgaJpZM4VFUrc> .

xabbuh · 2018-07-08T19:12:04Z

How do you use it with other types if you do not want to fail on null? I mean do you rely on implicit type casts here?

theofidry · 2018-07-08T21:52:15Z

No we do explicit casts in your blank validator. We don't rely on empty() and if the value is null we don't validate it with this constraint

xabbuh · 2018-07-09T07:21:02Z

Well, my point is I don't see a use case for the NotBlank constraint when you are not validating a string. For other types there are better constraints IMO. Based on this assumption we only need to discuss whether or not we need to distinguish null from the empty string which brings us back to the question if we need a shortcut for the Length constraint with a minimum length of 1.

ogizanagi · 2018-07-09T07:44:26Z

@xabbuh : The issue with the Length constraint is that it ignores empty strings:

symfony/src/Symfony/Component/Validator/Constraints/LengthValidator.php

Lines 32 to 34 in b226859

    
           if (null === $value || '' === $value) { 
        
               return; 
        
           }

theofidry · 2018-07-09T07:52:28Z

Which makes no sense to me neither tbh...

ostrolucky · 2018-07-09T09:48:26Z

You can also use NotEqualTo with ''

theofidry · 2018-07-09T09:49:18Z

@ostrolucky there is workarounds, we are not arguying otherwise. We would like however to make those constraints more intuitive

Neirda24 · 2018-07-13T12:22:35Z

Definitely agreeing with @theofidry . When using any Constraints in symfony the first rule is "Do not validate what you are not supposed to", so I don't understand why there is a NotBlank validating null and a NotNull. maybe add something like allowNull in the NotBlank constraints but set it to deprecated...

We can always find a way to go around this of course. But to stay consistent with any other constraints I feel like null should not be tested by NotBlank...

ostrolucky · 2018-07-13T12:34:09Z

I don't agree for one. You can't deprecate that without majority agreeing. All I see is loud minority. What you guys want can be achieved with other constraints like Length and NotEqualTo, what NotBlank does currently can't be replaced with any other single constraint, only with multiple.

theofidry · 2018-07-13T12:38:31Z

Again, we are not arguing we cannot achieve what we want. There is several workarounds available for them and we already discussed about them here. Our point is that the default behaviour is confusing and intuitive. That you consider it to be a loud minority and not a design/UX issue is another story and up for debate and why this issue has been created.

ostrolucky · 2018-07-13T12:54:59Z

Seems intuitive to me. Null is blank, NotBlank prevents blank values.

Neirda24 · 2018-07-13T14:17:03Z

I know this can be a huge debate but for me "the absence of value" does not mean "a blank value". Also empty in PHP also applies to arrays. So [] is empty but is not blank... (another reason why I also find it not intuitive).

Taluu · 2018-07-13T14:39:07Z

Adding an option allowNull (or something like that), defaulting to false would be a good BC imo, and would solve the current problem (and why not remove it on 5.0 ?). As @Neirda24 said, a null value is "no value" rather than "blank value"...

zanbaldwin · 2018-09-19T16:13:51Z

This is definitely an issue, especially as null values are common in APIs which Symfony is being used to build more and more.

Rather than deprecating existing validators/constraints (NotBlank should probably remain as it is because the Form component was historically built for web forms), it might be a good idea to create a new one (as mentioned above) that compliments the already existing two:

A NotEmpty constraint would work exactly the same as NotBlank except allowing null values.
The combination of NotNull and NotEmpty would be equivalent to NotBlank.
APIs get a really useful constraint, whilst preserving backwards-compatibility.

I had a little play with what that might look like and came up with the following that should cover most data types an API would receive. It probably needs tidying up a bit if anyone thinks this is a good idea.

/**
 * @Annotation
 * @Target({"PROPERTY", "METHOD", "ANNOTATION"})
 */
class NotEmpty extends Constraint
{
    public const IS_EMPTY_ERROR = '1034929d-a83b-4817-a722-0a4a9266067a';

    protected static $errorNames = array(
        self::IS_EMPTY_ERROR => 'IS_EMPTY_ERROR',
    );

    public $message = 'This value should not be empty, use null instead.';

    public function validatedBy(): string
    {
        return NotEmptyValidator::class;
    }
}

class NotEmptyValidator extends ConstraintValidator
{
    public function validate($value, Constraint $constraint)
    {
        if (!$constraint instanceof NotEmpty) {
            throw new UnexpectedTypeException($constraint, NotEmpty::class);
        }

        if ($value === null
            // Allow zero numerical values, etc.
            || (\is_scalar($value) && !\is_string($value))
            // Pure whitespace counts as being empty?
            || (\is_string($value) && \trim($value, " \r\n\t") !== '')
        ) {
            return;
        }

        if (empty($value) || (\is_string($value) && \trim($value, " \r\n\t") === '')) {
            $this->context->buildViolation($constraint->message)
                ->setParameter('{{ value }}', $this->formatValue($value))
                ->setCode(NotEmpty::IS_EMPTY_ERROR)
                ->addViolation();
        }
    }
}

dunglas · 2018-12-16T19:45:11Z

Adding an allow_null option is indeed a quick fix, and would help a lot when creating APIs. 👍 on my side.

…alues (dunglas) This PR was squashed before being merged into the 4.3-dev branch (closes #29641). Discussion ---------- [Validator] NotBlank: add a new option to allow null values | Q | A | ------------- | --- | Branch? | master | Bug fix? | no | New feature? | yes  | BC breaks? | no  | Deprecations? | no  | Tests pass? | yes  | Fixed tickets | #27876 | License | MIT | Doc PR | todo This PR adds a new option to the `@NotBlank` constraint to allow null values. As described in #27876, this is particularly useful when creating web APIs. Commits ------- 484d22a [Validator] NotBlank: add a new option to allow null values

…reject empty strings (ogizanagi) This PR was merged into the 4.4 branch. Discussion ---------- [Validator] Add a Length::$allowEmptyString option to reject empty strings | Q | A | ------------- | --- | Branch? | 4.4  | Bug fix? | no | New feature? | yes  | BC breaks? | no  | Deprecations? | yes  | Tests pass? | yes  | Fixed tickets | N/A  | License | MIT | Doc PR | Todo (change the warning on top of https://symfony.com/doc/current/reference/constraints/Length.html) which defaults to `true` in 4.4 but will trigger a deprecation if not set explicitly in order to make the default `false` in 5.0. While it could be solved now thanks to #29641 by using both `@Length(min=1)` & `@NotBlank(allowNull=true)` constraints, as expressed in symfony/symfony#27876 (comment) and following comments, the `@Length(min=1)` behavior doesn't match our expectations when reading it: it feels logical to invalidate empty strings, but it actually doesn't. Hence the proposal of making the behavior of rejecting empty strings the default in 5.0. In my opinion, the flag could even be removed later. Commits ------- e113e7f812 [Validator] Add a Length::$allowEmptyString option to reject empty strings

…reject empty strings (ogizanagi) This PR was merged into the 4.4 branch. Discussion ---------- [Validator] Add a Length::$allowEmptyString option to reject empty strings | Q | A | ------------- | --- | Branch? | 4.4  | Bug fix? | no | New feature? | yes  | BC breaks? | no  | Deprecations? | yes  | Tests pass? | yes  | Fixed tickets | N/A  | License | MIT | Doc PR | Todo (change the warning on top of https://symfony.com/doc/current/reference/constraints/Length.html) which defaults to `true` in 4.4 but will trigger a deprecation if not set explicitly in order to make the default `false` in 5.0. While it could be solved now thanks to #29641 by using both `@Length(min=1)` & `@NotBlank(allowNull=true)` constraints, as expressed in #27876 (comment) and following comments, the `@Length(min=1)` behavior doesn't match our expectations when reading it: it feels logical to invalidate empty strings, but it actually doesn't. Hence the proposal of making the behavior of rejecting empty strings the default in 5.0. In my opinion, the flag could even be removed later. Commits ------- e113e7f [Validator] Add a Length::$allowEmptyString option to reject empty strings

…reject empty strings (ogizanagi) This PR was merged into the 4.4 branch. Discussion ---------- [Validator] Add a Length::$allowEmptyString option to reject empty strings | Q | A | ------------- | --- | Branch? | 4.4  | Bug fix? | no | New feature? | yes  | BC breaks? | no  | Deprecations? | yes  | Tests pass? | yes  | Fixed tickets | N/A  | License | MIT | Doc PR | Todo (change the warning on top of https://symfony.com/doc/current/reference/constraints/Length.html) which defaults to `true` in 4.4 but will trigger a deprecation if not set explicitly in order to make the default `false` in 5.0. While it could be solved now thanks to #29641 by using both `@Length(min=1)` & `@NotBlank(allowNull=true)` constraints, as expressed in symfony/symfony#27876 (comment) and following comments, the `@Length(min=1)` behavior doesn't match our expectations when reading it: it feels logical to invalidate empty strings, but it actually doesn't. Hence the proposal of making the behavior of rejecting empty strings the default in 5.0. In my opinion, the flag could even be removed later. Commits ------- e113e7f812 [Validator] Add a Length::$allowEmptyString option to reject empty strings

xabbuh added Validator RFC RFC = Request For Comments (proposals about features that you want to be discussed) labels Jul 6, 2018

xabbuh mentioned this issue Sep 24, 2018

[3.0] [Validator] Remove Blank/NotBlank constraint #12300

Closed

ro0NL mentioned this issue Sep 26, 2018

[RFC] Improve bean validation #28611

Closed

dunglas mentioned this issue Dec 18, 2018

[Validator] NotBlank: add a new option to allow null values #29641

Merged

fabpot closed this as completed Jan 29, 2019

ogizanagi mentioned this issue May 17, 2019

[Validator] Add a Length::$allowEmptyString option to reject empty strings #31528

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NotBlank validator should not invalidate null values #27876

NotBlank validator should not invalidate null values #27876

Taluu commented Jul 6, 2018

stof commented Jul 6, 2018

theofidry commented Jul 8, 2018

ostrolucky commented Jul 8, 2018

theofidry commented Jul 8, 2018

ostrolucky commented Jul 8, 2018

theofidry commented Jul 8, 2018

xabbuh commented Jul 8, 2018

theofidry commented Jul 8, 2018 via email

xabbuh commented Jul 8, 2018

theofidry commented Jul 8, 2018

xabbuh commented Jul 9, 2018

ogizanagi commented Jul 9, 2018

theofidry commented Jul 9, 2018

ostrolucky commented Jul 9, 2018

theofidry commented Jul 9, 2018 •

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Neirda24 commented Jul 13, 2018

ostrolucky commented Jul 13, 2018

theofidry commented Jul 13, 2018

ostrolucky commented Jul 13, 2018

Neirda24 commented Jul 13, 2018

Taluu commented Jul 13, 2018

zanbaldwin commented Sep 19, 2018

dunglas commented Dec 16, 2018 •

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NotBlank validator should not invalidate null values #27876

NotBlank validator should not invalidate null values #27876

Comments

Taluu commented Jul 6, 2018

stof commented Jul 6, 2018

theofidry commented Jul 8, 2018

ostrolucky commented Jul 8, 2018

theofidry commented Jul 8, 2018

ostrolucky commented Jul 8, 2018

theofidry commented Jul 8, 2018

xabbuh commented Jul 8, 2018

theofidry commented Jul 8, 2018 via email

xabbuh commented Jul 8, 2018

theofidry commented Jul 8, 2018

xabbuh commented Jul 9, 2018

ogizanagi commented Jul 9, 2018

theofidry commented Jul 9, 2018

ostrolucky commented Jul 9, 2018

theofidry commented Jul 9, 2018 • edited Loading

Neirda24 commented Jul 13, 2018

ostrolucky commented Jul 13, 2018

theofidry commented Jul 13, 2018

ostrolucky commented Jul 13, 2018

Neirda24 commented Jul 13, 2018

Taluu commented Jul 13, 2018

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