General : Fixed copying bug when presentation had multiple slides

[dees040]

If in the original code you would add a dump of the slide collection like the example below and try to copy a presentation with three slides you'll get an exception:

Undefined array key 2

The code:

public function copy(): self
{
    $copied = clone $this;

    $slideCount = count($this->slideCollection);
    for ($i = 0; $i < $slideCount; ++$i) {
        var_dump(array_keys($this->slideCollection));

        $this->slideCollection[$i] = $this->slideCollection[$i]->copy();
        $this->slideCollection[$i]->rebindParent($this);
    }

    return $copied;
}

The dump output:

array:3 [ // vendor/phpoffice/phppresentation/src/PhpPresentation/PhpPresentation.php:325
  0 => 0
  1 => 1
  2 => 2
]
array:2 [ // vendor/phpoffice/phppresentation/src/PhpPresentation/PhpPresentation.php:325
  0 => 0
  1 => 1
]
array:1 [ // vendor/phpoffice/phppresentation/src/PhpPresentation/PhpPresentation.php:325
  0 => 0
]

Because of the rebindParent() which is being called on the copied slide, the copied presentation's original $slideCollection is being edited. This causes the code to break. This PR fixes that problem by saving the original $slideCollection before starting the slide copying process. Afterwards we set the new slide collection to the new copied presentation and also revert the original contact of the old presentation which is being copied.

I've also updated the unit test so that a presentation with multiple slides is being copied. If you test the unit test without the changes in PhpOffice\PhpPresentation\PhpPresentation you can also see the exception being thrown:

There was 1 error:

1. PhpOffice\PhpPresentation\Tests\PhpPresentationTest::testCopy
   Error: Call to a member function copy() on null

/PHPPresentation/src/PhpPresentation/PhpPresentation.php:316
/PHPPresentation/tests/PhpPresentation/Tests/PhpPresentationTest.php:90

ERRORS!
Tests: 1, Assertions: 0, Errors: 1, Warnings: 2, Deprecations: 1.

[Progi1984]

@dees040 I approve your PR. Could you update the changelog file 1.1.0.md before I merge it ?

[dees040]

@Progi1984 thanks! And of course. I wasn't sure what to put before the semicolon so I just did General. Let me know if I should change that to something else.

[Progi1984]

@dees040 Perfect

[Progi1984]

🎉 Thank you @dees040 for your contribution 🎉

[dees040]

My pleasure @Progi1984! Any chance version 1.1 can be tagged?