is_front_page flag affected by frontpage ID and page Title strange conflict

[m_i_n]

I want to report a strange bug. The is_front_page flag has incorrect value in cases like described below:

Front page in Settings / Reading is set to a static page: ​http://i.imgur.com/DzrbOVM.png
This Sample Page ID is 2
If you visit any other page, all is fine. For example the Lorem ipsum page: ​http://i.imgur.com/n5M0x8R.png
However, if you change title of this page to be the same as ID of a frontpage - in my case 2, then the is_front_page flag changes value to incorrect: ​http://i.imgur.com/KCa1JYo.png

It happens for titles like: 2, 02, 000002. Basically always if (int)$page_title == $front_page_id

The wrong is_front_page flag may affect themes/plugins which use it.

It's quite rare for the bug to take effect, but it happens, as I got a report from a user of my theme.

[tyxla]

That's such an interesting bug.

This is caused by the (expected) ambiguous behavior of the is_page() conditional tag, which is used within is_front_page().

As the documentation states, is_page() accepts: Page ID, title, slug, path, or array of such, so in that case 2 is being accepted as title, which is why the is_front_page() function returns true.

Patch with a fix is coming in a minute.

[tyxla]

Fixing is_front_page() conflicts with the titles of other page when they are the same like the ID of the front page. Including a unit test for that case.

[DrewAPicture]

#31009 was marked as a duplicate.

[MikeHansenMe]

Tested this and it worked as expected. Unit test also passes.

This code change updates original changes from the trac ticket below, to match the current code from WordPress Trunk. Everything should match what the original patch submitter added, with the exception of strict type checking between integers.

Trac ticket: See https://core.trac.wordpress.org/ticket/31711

@tw2113 The unit tests going failed, could you please check it?

Still checking on the unit test portion.

Notes for future me:

7) Tests_Query_Conditionals::test_page_on_front
is_front_page is false but is expected to be true.

/var/www/tests/phpunit/includes/abstract-testcase.php:1145
/var/www/tests/phpunit/tests/query/conditionals.php:49
/var/www/vendor/bin/phpunit:122

8) Tests_Query_Conditionals::test_is_front_page_id_equals_the_title_of_other_page
Failed asserting that false is true.

/var/www/tests/phpunit/tests/query/conditionals.php:1321
/var/www/vendor/bin/phpunit:122

9) Tests_Query_VerbosePageRules::test_page_on_front
is_front_page is false but is expected to be true.

/var/www/tests/phpunit/includes/abstract-testcase.php:1145
/var/www/tests/phpunit/tests/query/conditionals.php:49
/var/www/vendor/bin/phpunit:122

10) Tests_Query_VerbosePageRules::test_is_front_page_id_equals_the_title_of_other_page
Failed asserting that false is true.

/var/www/tests/phpunit/tests/query/conditionals.php:1321
/var/www/vendor/bin/phpunit:122

@mukeshpanchal27 This is ready for re-review after fixing strict type checking.

Thanks.