PHP 7.1 & PHP "Nightly" error: [] operator not supported for strings

[netweb]

bbPress is currently seeing 3 instances of the error [] operator not supported for strings on PHP 7.1 and PHP "nightly" jobs on Travis CI

• PHP 7.1: ​https://travis-ci.org/ntwb/bbPress/jobs/156094048
• PHP "Nightly": ​https://travis-ci.org/ntwb/bbPress/jobs/156094051

There were 3 errors:

1) BBP_Tests_Forums_Template_Forum::test_bbp_get_forum_permalink
Error: [] operator not supported for strings

/tmp/wordpress/src/wp-content/plugins/bbPress/src/includes/forums/functions.php:2250
/tmp/wordpress/src/wp-includes/plugin.php:602
/tmp/wordpress/src/wp-includes/class-wp-query.php:1682
/tmp/wordpress/src/wp-includes/class-wp-query.php:3238
/tmp/wordpress/src/wp-includes/post.php:1595
/tmp/wordpress/src/wp-content/plugins/bbPress/src/includes/forums/functions.php:1527
/tmp/wordpress/src/wp-content/plugins/bbPress/src/includes/forums/functions.php:1946
/tmp/wordpress/src/wp-content/plugins/bbPress/src/includes/forums/functions.php:73
/tmp/wordpress/src/wp-content/plugins/bbPress/tests/phpunit/includes/factory.php:31
/tmp/wordpress/tests/phpunit/includes/factory/class-wp-unittest-factory-for-thing.php:32
/tmp/wordpress/src/wp-content/plugins/bbPress/tests/phpunit/testcases/forums/template/forum.php:87

2) BBP_Tests_Forums_Template_Visibility::test_bbp_get_forum_visibility
Error: [] operator not supported for strings

/tmp/wordpress/src/wp-content/plugins/bbPress/src/includes/forums/functions.php:2250
/tmp/wordpress/src/wp-includes/plugin.php:602
/tmp/wordpress/src/wp-includes/class-wp-query.php:1682
/tmp/wordpress/src/wp-includes/class-wp-query.php:3238
/tmp/wordpress/src/wp-includes/post.php:1595
/tmp/wordpress/src/wp-content/plugins/bbPress/src/includes/forums/functions.php:1527
/tmp/wordpress/src/wp-content/plugins/bbPress/src/includes/forums/functions.php:1946
/tmp/wordpress/src/wp-content/plugins/bbPress/src/includes/forums/functions.php:73
/tmp/wordpress/src/wp-content/plugins/bbPress/tests/phpunit/includes/factory.php:31
/tmp/wordpress/tests/phpunit/includes/factory/class-wp-unittest-factory-for-thing.php:32
/tmp/wordpress/src/wp-content/plugins/bbPress/tests/phpunit/testcases/forums/template/visibility.php:28

3) BBP_Tests_Forums_Template_Visibility::test_bbp_is_forum_visibility
Error: [] operator not supported for strings

/tmp/wordpress/src/wp-content/plugins/bbPress/src/includes/forums/functions.php:2250
/tmp/wordpress/src/wp-includes/plugin.php:602
/tmp/wordpress/src/wp-includes/class-wp-query.php:1682
/tmp/wordpress/src/wp-includes/class-wp-query.php:3238
/tmp/wordpress/src/wp-includes/post.php:1595
/tmp/wordpress/src/wp-content/plugins/bbPress/src/includes/forums/functions.php:1527
/tmp/wordpress/src/wp-content/plugins/bbPress/src/includes/forums/functions.php:1946
/tmp/wordpress/src/wp-content/plugins/bbPress/src/includes/forums/functions.php:73
/tmp/wordpress/src/wp-content/plugins/bbPress/tests/phpunit/includes/factory.php:31
/tmp/wordpress/tests/phpunit/includes/factory/class-wp-unittest-factory-for-thing.php:32
/tmp/wordpress/src/wp-content/plugins/bbPress/tests/phpunit/testcases/forums/template/visibility.php:52

[netweb]

Related: #2973

[thebrandonallen]

WP_Query:get() defaults to returning an empty string if the requested key isn't set. However, you can pass a default return value. Attached patch sets the default return to an empty array. Tests now pass.

[netweb]

In 6113:

General: Set the default return to an empty array in $posts_query->get() in bbp_pre_get_posts_normalize_forum_visibility()

This changeset fixes PHP 7.1 warnings [] operator not supported for strings due to WP_Query:get() defaulting to returning an empty string if the requested key isn't set. However, you can pass a default return value. This commit sets the default return to an empty array.

Props thebrandonallen.
Fixes #2987.

[johnjamesjacoby]

In 6212:

Parser: PHP 7.1 compatibility fixes to parser.php

Props xknown. Fixes #2973. See #2987.

[netweb]

Merged r6212 upstream into bbPress' fork of NBBC ​https://github.com/bbpress/NBBC/pull/1

[netweb]

In 6417:

General: Set the default return to an empty array in $posts_query->get() in bbp_pre_get_posts_normalize_forum_visibility()

This changeset fixes PHP 7.1 warnings [] operator not supported for strings due to WP_Query:get() defaulting to returning an empty string if the requested key isn't set. However, you can pass a default return value. This commit sets the default return to an empty array.

Props thebrandonallen.
See #2987.

Merges [6113] to the 2.5 branch.

[netweb]

In 6418:

Parser: PHP 7.1 compatibility fixes to parser.php

Props xknown.
See #2973, #2987.

Merges [6212] to the 2.5 branch.