Ticket #43986: 43986-1.diff

src/wp-admin/includes/class-wp-plugin-install-list-table.php

@@ -686 +686 @@
                         echo '</div></div>';
                 }
         }
+
+        /**
+         * Loads the filter hook to disable the plugin install button if PHP version not sufficient.
+         */
+        public function load_requires_php(){
+                add_filter( 'plugin_install_action_links', array( $this, 'disable_install_button' ), 10, 2 );
+        }
+
+        /**
+         * Filter plugin action links in Install Plugin page.
+         *
+         * @param array $action_links
+         * @param array $plugin
+         *
+         * @return array $action_links
+         */
+        public function disable_install_button( $action_links, $plugin ) {
+                $disable_button = '<button type="button" class="button button-disabled" disabled="disabled">';
+                $disable_button .= __( 'Cannot install' );
+                $disable_button .= '</button>';
+
+                if ( $plugin['requires_php'] &&
+                     version_compare( PHP_VERSION, $plugin['requires_php'], '<=' )
+                ) {
+                        unset( $action_links[0] );
+                        $action_links[] = __( 'PHP version too low' );
+                        $action_links[] = $disable_button;
+                        $action_links   = array_reverse( $action_links );
+                }
+
+                return $action_links;
+        }
+
 }

src/wp-admin/plugin-install.php

@@ -39 +39 @@
 }
 
 $wp_list_table->prepare_items();
+$wp_list_table->load_requires_php();
 
 $total_pages = $wp_list_table->get_pagination_arg( 'total_pages' );