db export: Avoid exec() in option probe

features/db-export.feature

@@ -147,3 +147,16 @@ Feature: Export a WordPress database
 
     When I try `wp db export --no-defaults --debug`
     Then STDERR should match #Debug \(db\): Running initial shell command: /usr/bin/env (mysqldump|mariadb-dump) --no-defaults#
+
+  @skip-sqlite
+  @skip-windows
+  Scenario: Export database when PHP exec() is disabled
+    Given a WP install
+
+    When I try `{INVOKE_WP_CLI_WITH_PHP_ARGS--ddisable_functions=exec} db export wp_cli_test.sql --porcelain`
+    Then the return code should be 0
+    And STDOUT should contain:
+      """
+      wp_cli_test.sql
+      """
+    And the wp_cli_test.sql file should exist

src/DB_Command.php

@@ -1,6 +1,7 @@
 <?php
 
 use WP_CLI\Formatter;
+use WP_CLI\Process;
 use WP_CLI\Utils;
 use cli\table\Column;
 
@@ -747,7 +748,7 @@ public function export( $args, $assoc_args ) {
 
 		$mysqldump_binary = Utils\force_env_on_nix_systems( Utils\get_sql_dump_command() );
 
-		$support_column_statistics = exec( $mysqldump_binary . ' --help | grep "column-statistics"' );
+		$support_column_statistics = $this->command_supports_option( $mysqldump_binary, 'column-statistics' );
 
 		/*
 		 * In case that `--default-character-set` is not given and `DB_CHARSET` is `utf8`,
@@ -859,6 +860,19 @@ private function get_posts_table_charset( $assoc_args ) {
 		return $stdout;
 	}
 
+	/**
+	 * Check whether a shell command advertises support for a specific option in `--help`.
+	 *
+	 * @param string $command Base shell command to inspect.
+	 * @param string $option  Option name to look for.
+	 * @return bool Whether the option is listed in help output.
+	 */
+	private function command_supports_option( $command, $option ) {
+		$result = Process::create( "{$command} --help" )->run();
+
+		return false !== strpos( $result->stdout . $result->stderr, $option );
+	}
+
 	/**
 	 * Imports a database from a file or from STDIN.
 	 *