Ensure headers have not been sent before attempting to set a cookie

[kraftbj]

Changes proposed in this Pull Request:

• Checks for headers_sent before setting a cookie.

This can be seen via wp jetpack module activate minileven which results a notice in the logs:

[17-Dec-2019 23:07:31 UTC] PHP Warning:  Cannot modify header information - headers already sent by (output started at /usr/local/bin/psysh:1) in /var/www/html/wp-content/plugins/jetpack/class.jetpack.php on line 5617
[17-Dec-2019 23:07:31 UTC] PHP Stack trace:
[17-Dec-2019 23:07:31 UTC] PHP   1. {main}() /usr/local/bin/wp:0
[17-Dec-2019 23:07:31 UTC] PHP   2. include() /usr/local/bin/wp:4
[17-Dec-2019 23:07:31 UTC] PHP   3. include() phar:///usr/local/bin/wp/php/boot-phar.php:11
[17-Dec-2019 23:07:31 UTC] PHP   4. WP_CLI\bootstrap() phar:///usr/local/bin/wp/vendor/wp-cli/wp-cli/php/wp-cli.php:27
[17-Dec-2019 23:07:31 UTC] PHP   5. WP_CLI\Bootstrap\LaunchRunner->process() phar:///usr/local/bin/wp/vendor/wp-cli/wp-cli/php/bootstrap.php:74
[17-Dec-2019 23:07:31 UTC] PHP   6. WP_CLI\Runner->start() phar:///usr/local/bin/wp/vendor/wp-cli/wp-cli/php/WP_CLI/Bootstrap/LaunchRunner.php:23
[17-Dec-2019 23:07:31 UTC] PHP   7. WP_CLI\Runner->run_command_and_exit() phar:///usr/local/bin/wp/vendor/wp-cli/wp-cli/php/WP_CLI/Runner.php:1160
[17-Dec-2019 23:07:31 UTC] PHP   8. WP_CLI\Runner->run_command() phar:///usr/local/bin/wp/vendor/wp-cli/wp-cli/php/WP_CLI/Runner.php:394
[17-Dec-2019 23:07:31 UTC] PHP   9. WP_CLI\Dispatcher\Subcommand->invoke() phar:///usr/local/bin/wp/vendor/wp-cli/wp-cli/php/WP_CLI/Runner.php:371
[17-Dec-2019 23:07:31 UTC] PHP  10. call_user_func:{phar:///usr/local/bin/wp/vendor/wp-cli/wp-cli/php/WP_CLI/Dispatcher/Subcommand.php:451}() phar:///usr/local/bin/wp/vendor/wp-cli/wp-cli/php/WP_CLI/Dispatcher/Subcommand.php:451
[17-Dec-2019 23:07:31 UTC] PHP  11. WP_CLI\Dispatcher\CommandFactory::WP_CLI\Dispatcher\{closure:phar:///usr/local/bin/wp/vendor/wp-cli/wp-cli/php/WP_CLI/Dispatcher/CommandFactory.php:95-102}() phar:///usr/local/bin/wp/vendor/wp-cli/wp-cli/php/WP_CLI/Dispatcher/Subcommand.php:451
[17-Dec-2019 23:07:31 UTC] PHP  12. call_user_func:{phar:///usr/local/bin/wp/vendor/wp-cli/wp-cli/php/WP_CLI/Dispatcher/CommandFactory.php:98}() phar:///usr/local/bin/wp/vendor/wp-cli/wp-cli/php/WP_CLI/Dispatcher/CommandFactory.php:98
[17-Dec-2019 23:07:31 UTC] PHP  13. Jetpack_CLI->module() phar:///usr/local/bin/wp/vendor/wp-cli/wp-cli/php/WP_CLI/Dispatcher/CommandFactory.php:98
[17-Dec-2019 23:07:31 UTC] PHP  14. Jetpack::activate_module() /var/www/html/wp-content/plugins/jetpack/class.jetpack-cli.php:531
[17-Dec-2019 23:07:31 UTC] PHP  15. Jetpack::state() /var/www/html/wp-content/plugins/jetpack/class.jetpack.php:3041
[17-Dec-2019 23:07:31 UTC] PHP  16. setcookie() /var/www/html/wp-content/plugins/jetpack/class.jetpack.php:5617

Is this a new feature or does it add/remove features to an existing part of Jetpack?

• n/a

Testing instructions:

• See above.

Proposed changelog entry for your changes:

• CLI: Prevents a PHP notice when running some Jetpack CLI commands.

[jetpackbot]

Thank you for the great PR description!

When this PR is ready for review, please apply the [Status] Needs Review label. If you are an a11n, please have someone from your team review the code if possible. The Jetpack team will also review this PR and merge it to be included in the next Jetpack release.

Scheduled Jetpack release: January 14, 2020.
Scheduled code freeze: January 7, 2020

Generated by 🚫 dangerJS against 328b173

[jeherve]

This makes sense, however I can't seem to be able to reproduce the original issue. Was this happening in a specific PR?

[kraftbj]

@jeherve It was in my logs after testing the Mobile Theme deprecation PR via yarn docker:wp...

[brbrr]

Tests well 🚢