General: require PHP 5.3+ to be able to run Jetpack. (#12395)

* General: require PHP 5.3+ to be able to run Jetpack.

If a site runs WP 5.1 (where the PHP requirements are still PHP 5.2) and updates Jetpack:
1. We pause Jetpack (stop loading it).
2. We display an admin notice inviting folks to update PHP.
3. If WP_DEBUG is on, we log an error.

* Add comment to remind us to remove code once WP 5.2 is the min v.

* Removing PHP 5.2 testing since Jetpack does not support it anymore

.travis.yml

@@ -29,12 +29,6 @@ env:
 # so it doesn't need to be re-defined below.
 matrix:
   include:
-  # The versions listed below run within Precise distro with PHP 5.2 due to Travis limitation
-  # Hard-coding the versions since WP 5.2 has a PHP 5.6 minimum support.
-  # When removing this, remove corresponding setup functions in setup-travis.sh.
-  - php: "5.2"
-    env: WP_MODE=single WP_BRANCH=5.1
-    dist: precise
   - if: branch !~ /(^branch-.*-built)/
     language: node_js
     env: WP_TRAVISCI="yarn lint"

jetpack.php

@@ -13,6 +13,7 @@
  */
 
 define( 'JETPACK__MINIMUM_WP_VERSION', '5.1' );
+define( 'JETPACK__MINIMUM_PHP_VERSION', '5.3' );
 
 define( 'JETPACK__VERSION',            '7.4-alpha' );
 define( 'JETPACK_MASTER_USER',         true );
@@ -93,6 +94,45 @@ function jetpack_admin_unsupported_wp_notice() { ?>
 	return;
 }
 
+/**
+ * Outputs an admin notice for folks running an outdated version of PHP.
+ * @todo: Remove once WP 5.2 is the minimum version.
+ *
+ * @since 7.4.0
+ */
+function jetpack_admin_unsupported_php_notice() { ?>
+	<div class="notice notice-error is-dismissible">
+		<p><?php esc_html_e( 'Jetpack requires a more recent version of PHP and has been paused. Please update PHP to continue enjoying Jetpack.', 'jetpack' ); ?></p>
+		<p class="button-container">
+		<?php
+		printf(
+			'<a class="button button-primary" href="%1$s" target="_blank" rel="noopener noreferrer">%2$s <span class="screen-reader-text">%3$s</span><span aria-hidden="true" class="dashicons dashicons-external"></span></a>',
+			esc_url( wp_get_update_php_url() ),
+			__( 'Learn more about updating PHP' ),
+			/* translators: accessibility text */
+			__( '(opens in a new tab)' )
+		);
+		?>
+	</p>
+	</div>
+	<?php
+}
+
+if ( version_compare( phpversion(), JETPACK__MINIMUM_PHP_VERSION, '<' ) ) {
+	if ( defined( 'WP_DEBUG' ) && WP_DEBUG ) {
+		error_log(
+			sprintf(
+				/* translators: Placeholders are numbers, versions of PHP in use on the site, and required by Jetpack. */
+				esc_html__( 'Your version of PHP (%1$s) is lower than the version required by Jetpack (%2$s). Please update PHP to continue enjoying Jetpack.', 'jetpack' ),
+				esc_html( phpversion() ),
+				JETPACK__MINIMUM_PHP_VERSION
+			)
+		);
+	}
+	add_action( 'admin_notices', 'jetpack_admin_unsupported_php_notice' );
+	return;
+}
+
 add_filter( 'jetpack_require_lib_dir', 'jetpack_require_lib_dir' );
 add_filter( 'jetpack_should_use_minified_assets', 'jetpack_should_use_minified_assets', 9 );
 

readme.txt

@@ -3,6 +3,7 @@ Contributors: automattic, adamkheckler, aduth, akirk, allendav, alternatekev, an
 Tags: Jetpack, WordPress.com, backup, security, related posts, CDN, speed, anti-spam, social sharing, SEO, video, stats
 Stable tag: 7.3.1
 Requires at least: 5.0
+Requires PHP: 5.3
 Tested up to: 5.2
 
 The ideal plugin for stats, related posts, search engine optimization, social sharing, protection, backups, security, and more.

tests/setup-travis.sh

@@ -30,12 +30,6 @@ latest)
 previous)
 	git clone --depth=1 --branch $(php ./tests/get-wp-version.php --previous) git://develop.git.wordpress.org/ /tmp/wordpress-previous
 	;;
-5.0)
-	git clone --depth=1 --branch 5.0 git://develop.git.wordpress.org/ /tmp/wordpress-5.0
-	;;
-5.1)
-	git clone --depth=1 --branch 5.1 git://develop.git.wordpress.org/ /tmp/wordpress-5.1
-	;;
 esac
 
 clone_exit_code=$?