[PHP] Improve validation on empty arrays

[ackintosh]

PR checklist

• Read the contribution guidelines.
• Ran the shell script under ./bin/ to update Petstore sample so that CIs can verify the change. (For instance, only need to run ./bin/{LANG}-petstore.sh and ./bin/security/{LANG}-petstore.sh if updating the {LANG} (e.g. php, ruby, python, etc) code generator or {LANG} client's mustache templates). Windows batch files can be found in .\bin\windows\.
• Filed the PR against the correct branch: 3.0.0 branch for changes related to OpenAPI spec 3.0. Default: master.
• Copied the technical committee to review the pull request if your PR is targeting a particular programming language.

Description of the PR

refs #7675 (comment)

PetApi::findPetsByStatus() should throw an exception if an empty array is passed.

[ackintosh]

@jebentier @dkarlovi @mandrean @jfastnacht

[wing328]

@ackintosh The enhancement to check for empty array looks good to me 👍

[wing328]

Shall we do the same for the model template: https://github.com/ackintosh/swagger-codegen/blob/332956de362f19162b56486899686b860583327c/modules/swagger-codegen/src/main/resources/php/model_generic.mustache#L189-L193?

[ackintosh]

👀 ! Thanks, I'll do that.

[ackintosh]

Ah, the check for empty array in model may not needed. Because:

• model takes a single value (not multiple)
• passed value to model will be checked here whether it's valid

So empty array is always detected as an invalid value.

---

While I was investigating the above, I realized two different problems. 💡

1. We should pass true as 3rd argument of in_array()

        $enum = new EnumTest([
            'enum_string'  => 0, // Invalid
            'enum_integer' => 1,
            'enum_number'  => 1.1,
        ]);

        var_dump($enum->listInvalidProperties());
        // array(0) {
        // }

        var_dump($enum->valid());
        // true

It is caused by in_array() without 3rd argument.

• model_generic.mustache#L197
• model_generic.mustache#L277

2. Non-required enum property is listed as invalid when omitted

        $enum = new EnumTest([
            'enum_string'  => 'UPPER',
            // 'enum_integer' => 1, Omit non-required property
            'enum_number'  => 1.1,
        ]);

        var_dump($enum->listInvalidProperties());
        // array(1) {
        //   [0] =>
        //   string(58) "invalid value for 'enum_integer', must be one of '1', '-1'"
        // }

        var_dump($enum->valid());
        // bool(false)

enum_integer is non-required property, but it is listed as invalid.