Avoid displaying default delimiter on regex fail

Author: danielbachhuber

features/search-replace.feature

@@ -381,6 +381,34 @@ Feature: Do global search/replace
       """
     And the return code should be 1
 
+    When I try `wp search-replace 'regex error)' '' --regex`
+    Then STDERR should be:
+      """
+      Error: The regex pattern 'regex error)' with default delimiter 'chr(1)' and no flags fails.
+      """
+    And the return code should be 1
+
+    When I try `wp search-replace 'regex error)' '' --regex --regex-flags=u`
+    Then STDERR should be:
+      """
+      Error: The regex pattern 'regex error)' with default delimiter 'chr(1)' and flags 'u' fails.
+      """
+    And the return code should be 1
+
+    When I try `wp search-replace 'regex error)' '' --regex --regex-delimiter=/`
+    Then STDERR should be:
+      """
+      Error: The regex '/regex error)/' fails.
+      """
+    And the return code should be 1
+
+    When I try `wp search-replace 'regex error)' '' --regex --regex-delimiter=/ --regex-flags=u`
+    Then STDERR should be:
+      """
+      Error: The regex '/regex error)/u' fails.
+      """
+    And the return code should be 1
+
   Scenario: Formatting as count-only
     Given a WP install
     And I run `wp option set foo 'ALPHA.example.com'`

src/Search_Replace_Command.php

@@ -163,11 +163,18 @@ public function __invoke( $args, $assoc_args ) {
 		$php_only        = \WP_CLI\Utils\get_flag_value( $assoc_args, 'precise' );
 		$this->recurse_objects = \WP_CLI\Utils\get_flag_value( $assoc_args, 'recurse-objects', true );
 		$this->verbose         =  \WP_CLI\Utils\get_flag_value( $assoc_args, 'verbose' );
-		$this->regex           =  \WP_CLI\Utils\get_flag_value( $assoc_args, 'regex' );
-		$this->regex_flags     =  \WP_CLI\Utils\get_flag_value( $assoc_args, 'regex-flags' );
-		$this->regex_delimiter =  \WP_CLI\Utils\get_flag_value( $assoc_args, 'regex-delimiter', chr( 1 ) );
 		$this->format          = \WP_CLI\Utils\get_flag_value( $assoc_args, 'format' );
 
+		if ( ( $this->regex = \WP_CLI\Utils\get_flag_value( $assoc_args, 'regex', false ) ) ) {
+			$this->regex_flags = \WP_CLI\Utils\get_flag_value( $assoc_args, 'regex-flags', false );
+			$default_regex_delimiter = false;
+			$this->regex_delimiter = \WP_CLI\Utils\get_flag_value( $assoc_args, 'regex-delimiter', '' );
+			if ( '' === $this->regex_delimiter ) {
+				$this->regex_delimiter = chr( 1 );
+				$default_regex_delimiter = true;
+			}
+		}
+
 		if ( ! empty( $this->regex ) ) {
 			if ( '' === $this->regex_delimiter ) {
 				$this->regex_delimiter = chr( 1 );
@@ -177,7 +184,13 @@ public function __invoke( $args, $assoc_args ) {
 			$search_regex .= $this->regex_delimiter;
 			$search_regex .= $this->regex_flags;
 			if ( false === @preg_match( $search_regex, '' ) ) {
-				\WP_CLI::error( "The regex '$search_regex' fails." );
+				if ( $default_regex_delimiter ) {
+					$flags_msg = $this->regex_flags ? "flags '$this->regex_flags'" : "no flags";
+					$msg = "The regex pattern '$old' with default delimiter 'chr(1)' and {$flags_msg} fails.";
+				} else {
+					$msg = "The regex '$search_regex' fails.";
+				}
+				WP_CLI::error( $msg );
 			}
 		}