From d130e94c182957469b7464ae12805e686343ff5a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jes=C3=BAs=20Amieiro?=
 <1667814+amieiro@users.noreply.github.com>
Date: Mon, 4 Nov 2024 11:26:31 +0100
Subject: [PATCH 1/9] Add the check for the leading and trailing spaces

---
 WordPress/Sniffs/WP/I18nSniff.php           | 44 +++++++++++++++++++++
 WordPress/Tests/WP/I18nUnitTest.1.inc       | 23 +++++++++++
 WordPress/Tests/WP/I18nUnitTest.1.inc.fixed | 23 +++++++++++
 WordPress/Tests/WP/I18nUnitTest.php         | 22 +++++++++++
 4 files changed, 112 insertions(+)

diff --git a/WordPress/Sniffs/WP/I18nSniff.php b/WordPress/Sniffs/WP/I18nSniff.php
index 33158ed08e..b740495386 100644
--- a/WordPress/Sniffs/WP/I18nSniff.php
+++ b/WordPress/Sniffs/WP/I18nSniff.php
@@ -380,6 +380,7 @@ public function process_parameters( $stackPtr, $group_name, $matched_content, $p
 				$has_content = $this->check_string_has_translatable_content( $matched_content, $param_name, $param_info );
 				if ( true === $has_content ) {
 					$this->check_string_has_no_html_wrapper( $matched_content, $param_name, $param_info );
+					$this->check_string_has_no_leading_trailing_spaces( $matched_content, $param_name, $param_info );
 				}
 			}
 		}
@@ -804,6 +805,49 @@ private function check_string_has_no_html_wrapper( $matched_content, $param_name
 		}
 	}
 
+	/**
+	 * Check if a translatable string has leading or trailing spaces.
+	 *
+	 * @since 3.2.0
+	 *
+	 * @param string      $matched_content The token content (function name) which was matched
+	 *                                     in lowercase.
+	 * @param string      $param_name      The name of the parameter being examined.
+	 * @param array|false $param_info      Parameter info array for an individual parameter,
+	 *                                     as received from the PassedParameters class.
+	 *
+	 * @return void
+	 */
+	private function check_string_has_no_leading_trailing_spaces( $matched_content, $param_name, $param_info ) {
+		// Strip surrounding quotes.
+		$content_without_quotes = TextStrings::stripQuotes( $param_info['clean'] );
+		$first_non_empty = $this->phpcsFile->findNext( Tokens::$emptyTokens, $param_info['start'], ( $param_info['end'] + 1 ), true );
+
+		if ( ltrim( $content_without_quotes ) !== $content_without_quotes ) {
+			$this->phpcsFile->addError(
+				'Translatable string should not have leading spaces. Found: %s',
+				$first_non_empty,
+				'NoLeadingTrailingSpaces',
+				array( $param_info['clean'] )
+			);
+		}
+		if ( rtrim( $content_without_quotes ) !== $content_without_quotes ) {
+			$this->phpcsFile->addError(
+				'Translatable string should not have trailing spaces. Found: %s',
+				$first_non_empty,
+				'NoLeadingTrailingSpaces',
+				array( $param_info['clean'] )
+			);
+		}
+
+		if ('cadena' == $param_info['raw']) {
+			fwrite(STDERR, "\n" . '$matched_content: ' . print_r($matched_content, TRUE));
+			fwrite(STDERR, "\n" . '$param_name: ' . print_r($param_name, TRUE));
+			fwrite(STDERR, "\n" . '$param_info: ' . print_r($param_info, TRUE));
+			exit(1);
+		}
+	}
+
 	/**
 	 * Check for inconsistencies in the placeholders between single and plural form of the translatable text string.
 	 *
diff --git a/WordPress/Tests/WP/I18nUnitTest.1.inc b/WordPress/Tests/WP/I18nUnitTest.1.inc
index 3abf8ec3ba..92b5cfff04 100644
--- a/WordPress/Tests/WP/I18nUnitTest.1.inc
+++ b/WordPress/Tests/WP/I18nUnitTest.1.inc
@@ -328,4 +328,27 @@ MyNamespace\__( 'foo', 'my-slug' ); // Ok.
 namespace\esc_html_e( 'foo', '' ); // The sniff should start flagging this once it can resolve relative namespaces.
 namespace\Sub\translate( 'foo', 'my-slug' ); // Ok.
 
+__( ' string', 'my-slug' ); // Bad: leading space.
+_e( 'string ', 'my-slug' ); // Bad: trailing space.
+_x( ' string ', 'context', 'my-slug' ); // Bad: leading and trailing spaces.
+_ex( '   string', 'context', 'my-slug' ); // Bad: leading spaces.
+_n( ' There is %1$d monkey in the %2$s', 'In the %2$s there are %1$d monkeys', $number, 'my-slug' ); // Bad: leading space.
+_n( 'There is %1$d monkey in the %2$s', 'In the %2$s there are %1$d monkeys ', $number, 'my-slug' ); // Bad: trailing space.
+_n( '  There is %1$d monkey in the %2$s', 'In the %2$s there are %1$d monkeys  ', $number, 'my-slug' ); // Bad: leading and trailing spaces.
+_nx( '  I have %d cat.', 'I have %d cats.', $number, 'Not really.', 'my-slug' ); // Bad: leading spaces.
+_nx( 'I have %d cat.', 'I have %d cats.  ', $number, 'Not really.', 'my-slug' ); // Bad: trailing spaces.
+_nx( '  I have %d cat.', 'I have %d cats.  ', $number, 'Not really.', 'my-slug' ); // Bad: leading and trailing spaces.
+_n_noop( ' I have %d cat.', 'I have %d cats.', 'my-slug' ); // Bad: leading space.
+_n_noop( 'I have %d cat.', 'I have %d cats. ', 'my-slug' ); // Bad: trailing space.
+_n_noop( ' I have %d cat.', 'I have %d cats. ', 'my-slug' ); // Bad: leading and trailing spaces.
+_nx_noop( '  I have %d cat.', 'I have %d cats.', 'Not really.', 'my-slug' ); // Bad: leading spaces.
+_nx_noop( 'I have %d cat.', 'I have %d cats.  ', 'Not really.', 'my-slug' ); // Bad: trailing spaces.
+_nx_noop( ' I have %d cat.', 'I have %d cats.   ', 'Not really.', 'my-slug' ); // Bad: leading and trailing spaces.
+esc_html__( ' string', 'my-slug' ); // Bad: leading space.
+esc_html_e( 'string ', 'my-slug' ); // Bad: trailing space.
+esc_html_x( ' string ', 'context', 'my-slug' ); // Bad: leading and trailing spaces.
+esc_attr__( ' string', 'my-slug' ); // Bad: leading space.
+esc_attr_e( 'string ', 'my-slug' ); // Bad: trailing space.
+esc_attr_x( ' string ', 'context', 'my-slug' ); // Bad: leading and trailing spaces.
+
 // phpcs:enable WordPress.WP.I18n.MissingTranslatorsComment
diff --git a/WordPress/Tests/WP/I18nUnitTest.1.inc.fixed b/WordPress/Tests/WP/I18nUnitTest.1.inc.fixed
index ae6358abbf..29735b8259 100644
--- a/WordPress/Tests/WP/I18nUnitTest.1.inc.fixed
+++ b/WordPress/Tests/WP/I18nUnitTest.1.inc.fixed
@@ -328,4 +328,27 @@ MyNamespace\__( 'foo', 'my-slug' ); // Ok.
 namespace\esc_html_e( 'foo', '' ); // The sniff should start flagging this once it can resolve relative namespaces.
 namespace\Sub\translate( 'foo', 'my-slug' ); // Ok.
 
+__( ' string', 'my-slug' ); // Bad: leading space.
+_e( 'string ', 'my-slug' ); // Bad: trailing space.
+_x( ' string ', 'context', 'my-slug' ); // Bad: leading and trailing spaces.
+_ex( '   string', 'context', 'my-slug' ); // Bad: leading spaces.
+_n( ' There is %1$d monkey in the %2$s', 'In the %2$s there are %1$d monkeys', $number, 'my-slug' ); // Bad: leading space.
+_n( 'There is %1$d monkey in the %2$s', 'In the %2$s there are %1$d monkeys ', $number, 'my-slug' ); // Bad: trailing space.
+_n( '  There is %1$d monkey in the %2$s', 'In the %2$s there are %1$d monkeys  ', $number, 'my-slug' ); // Bad: leading and trailing spaces.
+_nx( '  I have %d cat.', 'I have %d cats.', $number, 'Not really.', 'my-slug' ); // Bad: leading spaces.
+_nx( 'I have %d cat.', 'I have %d cats.  ', $number, 'Not really.', 'my-slug' ); // Bad: trailing spaces.
+_nx( '  I have %d cat.', 'I have %d cats.  ', $number, 'Not really.', 'my-slug' ); // Bad: leading and trailing spaces.
+_n_noop( ' I have %d cat.', 'I have %d cats.', 'my-slug' ); // Bad: leading space.
+_n_noop( 'I have %d cat.', 'I have %d cats. ', 'my-slug' ); // Bad: trailing space.
+_n_noop( ' I have %d cat.', 'I have %d cats. ', 'my-slug' ); // Bad: leading and trailing spaces.
+_nx_noop( '  I have %d cat.', 'I have %d cats.', 'Not really.', 'my-slug' ); // Bad: leading spaces.
+_nx_noop( 'I have %d cat.', 'I have %d cats.  ', 'Not really.', 'my-slug' ); // Bad: trailing spaces.
+_nx_noop( ' I have %d cat.', 'I have %d cats.   ', 'Not really.', 'my-slug' ); // Bad: leading and trailing spaces.
+esc_html__( ' string', 'my-slug' ); // Bad: leading space.
+esc_html_e( 'string ', 'my-slug' ); // Bad: trailing space.
+esc_html_x( ' string ', 'context', 'my-slug' ); // Bad: leading and trailing spaces.
+esc_attr__( ' string', 'my-slug' ); // Bad: leading space.
+esc_attr_e( 'string ', 'my-slug' ); // Bad: trailing space.
+esc_attr_x( ' string ', 'context', 'my-slug' ); // Bad: leading and trailing spaces.
+
 // phpcs:enable WordPress.WP.I18n.MissingTranslatorsComment
diff --git a/WordPress/Tests/WP/I18nUnitTest.php b/WordPress/Tests/WP/I18nUnitTest.php
index 20e7accaab..807bb97ac8 100644
--- a/WordPress/Tests/WP/I18nUnitTest.php
+++ b/WordPress/Tests/WP/I18nUnitTest.php
@@ -149,6 +149,28 @@ public function getErrorList( $testFile = '' ) {
 					315 => 1,
 					318 => 1,
 					323 => 1,
+					331 => 1,
+					332 => 1,
+					333 => 2,
+					334 => 1,
+					335 => 1,
+					336 => 1,
+					337 => 2,
+					338 => 1,
+					339 => 1,
+					340 => 2,
+					341 => 1,
+					342 => 1,
+					343 => 2,
+					344 => 1,
+					345 => 1,
+					346 => 2,
+					347 => 1,
+					348 => 1,
+					349 => 2,
+					350 => 1,
+					351 => 1,
+					352 => 2,
 				);
 
 			case 'I18nUnitTest.2.inc':

From 258b3a51af7ea94b0bfd90055069adeb05d398fa Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jes=C3=BAs=20Amieiro?=
 <1667814+amieiro@users.noreply.github.com>
Date: Mon, 4 Nov 2024 11:33:27 +0100
Subject: [PATCH 2/9] Remove a debug code

---
 WordPress/Sniffs/WP/I18nSniff.php | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/WordPress/Sniffs/WP/I18nSniff.php b/WordPress/Sniffs/WP/I18nSniff.php
index b740495386..9e24d0787d 100644
--- a/WordPress/Sniffs/WP/I18nSniff.php
+++ b/WordPress/Sniffs/WP/I18nSniff.php
@@ -839,13 +839,6 @@ private function check_string_has_no_leading_trailing_spaces( $matched_content,
 				array( $param_info['clean'] )
 			);
 		}
-
-		if ('cadena' == $param_info['raw']) {
-			fwrite(STDERR, "\n" . '$matched_content: ' . print_r($matched_content, TRUE));
-			fwrite(STDERR, "\n" . '$param_name: ' . print_r($param_name, TRUE));
-			fwrite(STDERR, "\n" . '$param_info: ' . print_r($param_info, TRUE));
-			exit(1);
-		}
 	}
 
 	/**

From c33ae936de80e5f16bc4b390f34ea17113336d3a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jes=C3=BAs=20Amieiro?=
 <1667814+amieiro@users.noreply.github.com>
Date: Mon, 4 Nov 2024 11:50:33 +0100
Subject: [PATCH 3/9] Lint

---
 WordPress/Sniffs/WP/I18nSniff.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/WordPress/Sniffs/WP/I18nSniff.php b/WordPress/Sniffs/WP/I18nSniff.php
index 9e24d0787d..82499c2ec6 100644
--- a/WordPress/Sniffs/WP/I18nSniff.php
+++ b/WordPress/Sniffs/WP/I18nSniff.php
@@ -821,7 +821,7 @@ private function check_string_has_no_html_wrapper( $matched_content, $param_name
 	private function check_string_has_no_leading_trailing_spaces( $matched_content, $param_name, $param_info ) {
 		// Strip surrounding quotes.
 		$content_without_quotes = TextStrings::stripQuotes( $param_info['clean'] );
-		$first_non_empty = $this->phpcsFile->findNext( Tokens::$emptyTokens, $param_info['start'], ( $param_info['end'] + 1 ), true );
+		$first_non_empty        = $this->phpcsFile->findNext( Tokens::$emptyTokens, $param_info['start'], ( $param_info['end'] + 1 ), true );
 
 		if ( ltrim( $content_without_quotes ) !== $content_without_quotes ) {
 			$this->phpcsFile->addError(

From 2fab295c62d1b9ef66d2d4147e3ec6ce27e67492 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jes=C3=BAs=20Amieiro?=
 <1667814+amieiro@users.noreply.github.com>
Date: Tue, 10 Jun 2025 19:10:05 +0200
Subject: [PATCH 4/9] Add tabs to the checks

---
 WordPress/Tests/WP/I18nUnitTest.1.inc       | 5 +++++
 WordPress/Tests/WP/I18nUnitTest.1.inc.fixed | 5 +++++
 WordPress/Tests/WP/I18nUnitTest.php         | 5 +++++
 3 files changed, 15 insertions(+)

diff --git a/WordPress/Tests/WP/I18nUnitTest.1.inc b/WordPress/Tests/WP/I18nUnitTest.1.inc
index 92b5cfff04..ca571f5b39 100644
--- a/WordPress/Tests/WP/I18nUnitTest.1.inc
+++ b/WordPress/Tests/WP/I18nUnitTest.1.inc
@@ -350,5 +350,10 @@ esc_html_x( ' string ', 'context', 'my-slug' ); // Bad: leading and trailing spa
 esc_attr__( ' string', 'my-slug' ); // Bad: leading space.
 esc_attr_e( 'string ', 'my-slug' ); // Bad: trailing space.
 esc_attr_x( ' string ', 'context', 'my-slug' ); // Bad: leading and trailing spaces.
+__( '	string', 'my-slug' ); // Bad: leading tab.
+__( 'string	', 'my-slug' ); // Bad: trailing tab.
+__( '	string	', 'my-slug' ); // Bad: leading and trailing tabs.
+__( '		string', 'my-slug' ); // Bad: two leading tabs.
+__( 'string		', 'my-slug' ); // Bad: two trailing tabs.
 
 // phpcs:enable WordPress.WP.I18n.MissingTranslatorsComment
diff --git a/WordPress/Tests/WP/I18nUnitTest.1.inc.fixed b/WordPress/Tests/WP/I18nUnitTest.1.inc.fixed
index 29735b8259..ce2cd730ad 100644
--- a/WordPress/Tests/WP/I18nUnitTest.1.inc.fixed
+++ b/WordPress/Tests/WP/I18nUnitTest.1.inc.fixed
@@ -350,5 +350,10 @@ esc_html_x( ' string ', 'context', 'my-slug' ); // Bad: leading and trailing spa
 esc_attr__( ' string', 'my-slug' ); // Bad: leading space.
 esc_attr_e( 'string ', 'my-slug' ); // Bad: trailing space.
 esc_attr_x( ' string ', 'context', 'my-slug' ); // Bad: leading and trailing spaces.
+__( '	string', 'my-slug' ); // Bad: leading tab.
+__( 'string	', 'my-slug' ); // Bad: trailing tab.
+__( '	string	', 'my-slug' ); // Bad: leading and trailing tabs.
+__( '		string', 'my-slug' ); // Bad: two leading tabs.
+__( 'string		', 'my-slug' ); // Bad: two trailing tabs.
 
 // phpcs:enable WordPress.WP.I18n.MissingTranslatorsComment
diff --git a/WordPress/Tests/WP/I18nUnitTest.php b/WordPress/Tests/WP/I18nUnitTest.php
index 807bb97ac8..9d7186d5cb 100644
--- a/WordPress/Tests/WP/I18nUnitTest.php
+++ b/WordPress/Tests/WP/I18nUnitTest.php
@@ -171,6 +171,11 @@ public function getErrorList( $testFile = '' ) {
 					350 => 1,
 					351 => 1,
 					352 => 2,
+					353 => 1,
+					354 => 1,
+					355 => 2,
+					356 => 1,
+					357 => 1,
 				);
 
 			case 'I18nUnitTest.2.inc':

From 409f1dda67eaca9205a09b6ab25f5434d32d8316 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jes=C3=BAs=20Amieiro?=
 <1667814+amieiro@users.noreply.github.com>
Date: Tue, 10 Jun 2025 19:35:44 +0200
Subject: [PATCH 5/9] Add new lines to the checks

---
 WordPress/Sniffs/WP/I18nSniff.php           |  4 ++--
 WordPress/Tests/WP/I18nUnitTest.1.inc       | 13 +++++++++++++
 WordPress/Tests/WP/I18nUnitTest.1.inc.fixed | 13 +++++++++++++
 WordPress/Tests/WP/I18nUnitTest.php         |  5 +++++
 4 files changed, 33 insertions(+), 2 deletions(-)

diff --git a/WordPress/Sniffs/WP/I18nSniff.php b/WordPress/Sniffs/WP/I18nSniff.php
index 82499c2ec6..c21de0f285 100644
--- a/WordPress/Sniffs/WP/I18nSniff.php
+++ b/WordPress/Sniffs/WP/I18nSniff.php
@@ -825,7 +825,7 @@ private function check_string_has_no_leading_trailing_spaces( $matched_content,
 
 		if ( ltrim( $content_without_quotes ) !== $content_without_quotes ) {
 			$this->phpcsFile->addError(
-				'Translatable string should not have leading spaces. Found: %s',
+				'Translatable string should not have leading spaces, tabs, or new lines. Found: %s',
 				$first_non_empty,
 				'NoLeadingTrailingSpaces',
 				array( $param_info['clean'] )
@@ -833,7 +833,7 @@ private function check_string_has_no_leading_trailing_spaces( $matched_content,
 		}
 		if ( rtrim( $content_without_quotes ) !== $content_without_quotes ) {
 			$this->phpcsFile->addError(
-				'Translatable string should not have trailing spaces. Found: %s',
+				'Translatable string should not have trailing spaces, tabs, or new lines. Found: %s',
 				$first_non_empty,
 				'NoLeadingTrailingSpaces',
 				array( $param_info['clean'] )
diff --git a/WordPress/Tests/WP/I18nUnitTest.1.inc b/WordPress/Tests/WP/I18nUnitTest.1.inc
index ca571f5b39..a4fce04768 100644
--- a/WordPress/Tests/WP/I18nUnitTest.1.inc
+++ b/WordPress/Tests/WP/I18nUnitTest.1.inc
@@ -355,5 +355,18 @@ __( 'string	', 'my-slug' ); // Bad: trailing tab.
 __( '	string	', 'my-slug' ); // Bad: leading and trailing tabs.
 __( '		string', 'my-slug' ); // Bad: two leading tabs.
 __( 'string		', 'my-slug' ); // Bad: two trailing tabs.
+__( '
+string', 'my-slug' ); // Bad: leading new line.
+__( 'string
+', 'my-slug' ); // Bad: trailing new line.
+__( '
+string
+', 'my-slug' ); // Bad: leading and trailing new line.
+__( '
+
+string', 'my-slug' ); // Bad: two leading new lines.
+__( 'string
+
+', 'my-slug' ); // Bad: two trailing new lines.
 
 // phpcs:enable WordPress.WP.I18n.MissingTranslatorsComment
diff --git a/WordPress/Tests/WP/I18nUnitTest.1.inc.fixed b/WordPress/Tests/WP/I18nUnitTest.1.inc.fixed
index ce2cd730ad..2b171abadb 100644
--- a/WordPress/Tests/WP/I18nUnitTest.1.inc.fixed
+++ b/WordPress/Tests/WP/I18nUnitTest.1.inc.fixed
@@ -355,5 +355,18 @@ __( 'string	', 'my-slug' ); // Bad: trailing tab.
 __( '	string	', 'my-slug' ); // Bad: leading and trailing tabs.
 __( '		string', 'my-slug' ); // Bad: two leading tabs.
 __( 'string		', 'my-slug' ); // Bad: two trailing tabs.
+__( '
+string', 'my-slug' ); // Bad: leading new line.
+__( 'string
+', 'my-slug' ); // Bad: trailing new line.
+__( '
+string
+', 'my-slug' ); // Bad: leading and trailing new line.
+__( '
+
+string', 'my-slug' ); // Bad: two leading new lines.
+__( 'string
+
+', 'my-slug' ); // Bad: two trailing new lines.
 
 // phpcs:enable WordPress.WP.I18n.MissingTranslatorsComment
diff --git a/WordPress/Tests/WP/I18nUnitTest.php b/WordPress/Tests/WP/I18nUnitTest.php
index 9d7186d5cb..db0450cadb 100644
--- a/WordPress/Tests/WP/I18nUnitTest.php
+++ b/WordPress/Tests/WP/I18nUnitTest.php
@@ -176,6 +176,11 @@ public function getErrorList( $testFile = '' ) {
 					355 => 2,
 					356 => 1,
 					357 => 1,
+					358 => 1,
+					360 => 1,
+					362 => 2,
+					365 => 1,
+					368 => 1,
 				);
 
 			case 'I18nUnitTest.2.inc':

From b2150810c18a4587192f5d790b85a211e911749a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jes=C3=BAs=20Amieiro?=
 <1667814+amieiro@users.noreply.github.com>
Date: Wed, 11 Jun 2025 06:55:54 +0200
Subject: [PATCH 6/9] Refactor the method to have different error messages for
 each check

---
 WordPress/Sniffs/WP/I18nSniff.php | 63 ++++++++++++++++++++++++++++---
 1 file changed, 57 insertions(+), 6 deletions(-)

diff --git a/WordPress/Sniffs/WP/I18nSniff.php b/WordPress/Sniffs/WP/I18nSniff.php
index c21de0f285..a53dff255b 100644
--- a/WordPress/Sniffs/WP/I18nSniff.php
+++ b/WordPress/Sniffs/WP/I18nSniff.php
@@ -823,19 +823,70 @@ private function check_string_has_no_leading_trailing_spaces( $matched_content,
 		$content_without_quotes = TextStrings::stripQuotes( $param_info['clean'] );
 		$first_non_empty        = $this->phpcsFile->findNext( Tokens::$emptyTokens, $param_info['start'], ( $param_info['end'] + 1 ), true );
 
-		if ( ltrim( $content_without_quotes ) !== $content_without_quotes ) {
+		// Define regex patterns.
+		$pattern_leading_spaces  = '/^[ ]+/u';
+		$pattern_trailing_spaces = '/[ ]+$/u';
+		$pattern_leading_tabs    = '/^\t+/u';
+		$pattern_trailing_tabs   = '/\t+$/u';
+		$pattern_leading_newlines = '/^[\r\n]+/u';
+		$pattern_trailing_newlines = '/[\r\n]+$/u';
+
+		// Check for leading spaces.
+		if ( preg_match( $pattern_leading_spaces, $content_without_quotes ) ) {
 			$this->phpcsFile->addError(
-				'Translatable string should not have leading spaces, tabs, or new lines. Found: %s',
+				'Translatable string should not have leading spaces. Found: %s',
 				$first_non_empty,
-				'NoLeadingTrailingSpaces',
+				'LeadingSpaces',
 				array( $param_info['clean'] )
 			);
 		}
-		if ( rtrim( $content_without_quotes ) !== $content_without_quotes ) {
+		
+		// Check for trailing spaces.
+		if ( preg_match( $pattern_trailing_spaces, $content_without_quotes ) ) {
 			$this->phpcsFile->addError(
-				'Translatable string should not have trailing spaces, tabs, or new lines. Found: %s',
+				'Translatable string should not have trailing spaces. Found: %s',
 				$first_non_empty,
-				'NoLeadingTrailingSpaces',
+				'TrailingSpaces',
+				array( $param_info['clean'] )
+			);
+		}
+		
+		// Check for leading tabs.
+		if ( preg_match( $pattern_leading_tabs, $content_without_quotes ) ) {
+			$this->phpcsFile->addError(
+				'Translatable string should not have leading tabs. Found: %s',
+				$first_non_empty,
+				'LeadingTabs',
+				array( $param_info['clean'] )
+			);
+		}
+		
+		// Check for trailing tabs.
+		if ( preg_match( $pattern_trailing_tabs, $content_without_quotes ) ) {
+			$this->phpcsFile->addError(
+				'Translatable string should not have trailing tabs. Found: %s',
+				$first_non_empty,
+				'TrailingTabs',
+				array( $param_info['clean'] )
+			);
+		}
+		
+		// Check for leading new lines.
+		if ( preg_match( $pattern_leading_newlines, $content_without_quotes ) ) {
+			$this->phpcsFile->addError(
+				'Translatable string should not have leading new lines. Found: %s',
+				$first_non_empty,
+				'LeadingNewLines',
+				array( $param_info['clean'] )
+			);
+		}
+		
+		// Check for trailing new lines.
+		if ( preg_match( $pattern_trailing_newlines, $content_without_quotes ) ) {
+			$this->phpcsFile->addError(
+				'Translatable string should not have trailing new lines. Found: %s',
+				$first_non_empty,
+				'TrailingNewLines',
 				array( $param_info['clean'] )
 			);
 		}

From 7dc4bd4380839ad3d33f17362434d1e98ebf5600 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jes=C3=BAs=20Amieiro?=
 <1667814+amieiro@users.noreply.github.com>
Date: Wed, 11 Jun 2025 07:25:27 +0200
Subject: [PATCH 7/9] Add vertical tabs to the checks

---
 WordPress/Sniffs/WP/I18nSniff.php           | 22 +++++++++++++++++++++
 WordPress/Tests/WP/I18nUnitTest.1.inc       |  5 +++++
 WordPress/Tests/WP/I18nUnitTest.1.inc.fixed |  5 +++++
 WordPress/Tests/WP/I18nUnitTest.php         |  5 +++++
 4 files changed, 37 insertions(+)

diff --git a/WordPress/Sniffs/WP/I18nSniff.php b/WordPress/Sniffs/WP/I18nSniff.php
index a53dff255b..c3829d2c13 100644
--- a/WordPress/Sniffs/WP/I18nSniff.php
+++ b/WordPress/Sniffs/WP/I18nSniff.php
@@ -830,6 +830,8 @@ private function check_string_has_no_leading_trailing_spaces( $matched_content,
 		$pattern_trailing_tabs   = '/\t+$/u';
 		$pattern_leading_newlines = '/^[\r\n]+/u';
 		$pattern_trailing_newlines = '/[\r\n]+$/u';
+		$pattern_leading_vtabs   = '/^\x0B+/u';
+		$pattern_trailing_vtabs  = '/\x0B+$/u';
 
 		// Check for leading spaces.
 		if ( preg_match( $pattern_leading_spaces, $content_without_quotes ) ) {
@@ -890,6 +892,26 @@ private function check_string_has_no_leading_trailing_spaces( $matched_content,
 				array( $param_info['clean'] )
 			);
 		}
+		
+		// Check for leading vertical tabs.
+		if ( preg_match( $pattern_leading_vtabs, $content_without_quotes ) ) {
+			$this->phpcsFile->addError(
+				'Translatable string should not have leading vertical tabs. Found: %s',
+				$first_non_empty,
+				'LeadingVTabs',
+				array( $param_info['clean'] )
+			);
+		}
+		
+		// Check for trailing vertical tabs.
+		if ( preg_match( $pattern_trailing_vtabs, $content_without_quotes ) ) {
+			$this->phpcsFile->addError(
+				'Translatable string should not have trailing vertical tabs. Found: %s',
+				$first_non_empty,
+				'TrailingVTabs',
+				array( $param_info['clean'] )
+			);
+		}
 	}
 
 	/**
diff --git a/WordPress/Tests/WP/I18nUnitTest.1.inc b/WordPress/Tests/WP/I18nUnitTest.1.inc
index a4fce04768..fb9bdf7828 100644
--- a/WordPress/Tests/WP/I18nUnitTest.1.inc
+++ b/WordPress/Tests/WP/I18nUnitTest.1.inc
@@ -368,5 +368,10 @@ string', 'my-slug' ); // Bad: two leading new lines.
 __( 'string
 
 ', 'my-slug' ); // Bad: two trailing new lines.
+__( "String with leading vertical tab", 'my-slug' ); // Bad, has leading vertical tab.
+__( "String with trailing vertical tab", 'my-slug' ); // Bad, has trailing vertical tab.
+__( "String with leading and trailing vertical tabs", 'my-slug' ); // Bad, has both leading and trailing vertical tabs.
+__( "String with 2 leading vertical tabs", 'my-slug' ); // Bad, has 2 leading vertical tabs.
+__( "String with 2 trailing vertical tabs", 'my-slug' ); // Bad, has 2 trailing vertical tabs.
 
 // phpcs:enable WordPress.WP.I18n.MissingTranslatorsComment
diff --git a/WordPress/Tests/WP/I18nUnitTest.1.inc.fixed b/WordPress/Tests/WP/I18nUnitTest.1.inc.fixed
index 2b171abadb..2c828c66d2 100644
--- a/WordPress/Tests/WP/I18nUnitTest.1.inc.fixed
+++ b/WordPress/Tests/WP/I18nUnitTest.1.inc.fixed
@@ -368,5 +368,10 @@ string', 'my-slug' ); // Bad: two leading new lines.
 __( 'string
 
 ', 'my-slug' ); // Bad: two trailing new lines.
+__( "String with leading vertical tab", 'my-slug' ); // Bad, has leading vertical tab.
+__( "String with trailing vertical tab", 'my-slug' ); // Bad, has trailing vertical tab.
+__( "String with leading and trailing vertical tabs", 'my-slug' ); // Bad, has both leading and trailing vertical tabs.
+__( "String with 2 leading vertical tabs", 'my-slug' ); // Bad, has 2 leading vertical tabs.
+__( "String with 2 trailing vertical tabs", 'my-slug' ); // Bad, has 2 trailing vertical tabs.
 
 // phpcs:enable WordPress.WP.I18n.MissingTranslatorsComment
diff --git a/WordPress/Tests/WP/I18nUnitTest.php b/WordPress/Tests/WP/I18nUnitTest.php
index db0450cadb..0eec46cdd9 100644
--- a/WordPress/Tests/WP/I18nUnitTest.php
+++ b/WordPress/Tests/WP/I18nUnitTest.php
@@ -181,6 +181,11 @@ public function getErrorList( $testFile = '' ) {
 					362 => 2,
 					365 => 1,
 					368 => 1,
+					371 => 1,
+					372 => 1,
+					373 => 2,
+					374 => 1,
+					375 => 1,
 				);
 
 			case 'I18nUnitTest.2.inc':

From b8b4fc5d2ebaa45fceffe6e78cd4c195e8e42546 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jes=C3=BAs=20Amieiro?=
 <1667814+amieiro@users.noreply.github.com>
Date: Fri, 13 Jun 2025 19:29:41 +0200
Subject: [PATCH 8/9] Change the regexs to use hex codes and reorganize some
 code

---
 WordPress/Sniffs/WP/I18nSniff.php           | 46 ++++++++++-----------
 WordPress/Tests/WP/I18nUnitTest.1.inc       | 10 ++---
 WordPress/Tests/WP/I18nUnitTest.1.inc.fixed | 10 ++---
 WordPress/Tests/WP/I18nUnitTest.php         | 16 +++----
 4 files changed, 41 insertions(+), 41 deletions(-)

diff --git a/WordPress/Sniffs/WP/I18nSniff.php b/WordPress/Sniffs/WP/I18nSniff.php
index c3829d2c13..e0a96580bb 100644
--- a/WordPress/Sniffs/WP/I18nSniff.php
+++ b/WordPress/Sniffs/WP/I18nSniff.php
@@ -824,14 +824,14 @@ private function check_string_has_no_leading_trailing_spaces( $matched_content,
 		$first_non_empty        = $this->phpcsFile->findNext( Tokens::$emptyTokens, $param_info['start'], ( $param_info['end'] + 1 ), true );
 
 		// Define regex patterns.
-		$pattern_leading_spaces  = '/^[ ]+/u';
-		$pattern_trailing_spaces = '/[ ]+$/u';
-		$pattern_leading_tabs    = '/^\t+/u';
-		$pattern_trailing_tabs   = '/\t+$/u';
-		$pattern_leading_newlines = '/^[\r\n]+/u';
-		$pattern_trailing_newlines = '/[\r\n]+$/u';
+		$pattern_leading_spaces  = '/^[\x20]+/u';
+		$pattern_trailing_spaces = '/[\x20]+$/u';
+		$pattern_leading_tabs    = '/^\x09+/u';
+		$pattern_trailing_tabs   = '/\x09+$/u';
 		$pattern_leading_vtabs   = '/^\x0B+/u';
 		$pattern_trailing_vtabs  = '/\x0B+$/u';
+		$pattern_leading_newlines = '/^\x0A+/u';
+		$pattern_trailing_newlines = '/\x0A+$/u';
 
 		// Check for leading spaces.
 		if ( preg_match( $pattern_leading_spaces, $content_without_quotes ) ) {
@@ -873,42 +873,42 @@ private function check_string_has_no_leading_trailing_spaces( $matched_content,
 			);
 		}
 		
-		// Check for leading new lines.
-		if ( preg_match( $pattern_leading_newlines, $content_without_quotes ) ) {
+		// Check for leading vertical tabs.
+		if ( preg_match( $pattern_leading_vtabs, $content_without_quotes ) ) {
 			$this->phpcsFile->addError(
-				'Translatable string should not have leading new lines. Found: %s',
+				'Translatable string should not have leading vertical tabs. Found: %s',
 				$first_non_empty,
-				'LeadingNewLines',
+				'LeadingVTabs',
 				array( $param_info['clean'] )
 			);
 		}
 		
-		// Check for trailing new lines.
-		if ( preg_match( $pattern_trailing_newlines, $content_without_quotes ) ) {
+		// Check for trailing vertical tabs.
+		if ( preg_match( $pattern_trailing_vtabs, $content_without_quotes ) ) {
 			$this->phpcsFile->addError(
-				'Translatable string should not have trailing new lines. Found: %s',
+				'Translatable string should not have trailing vertical tabs. Found: %s',
 				$first_non_empty,
-				'TrailingNewLines',
+				'TrailingVTabs',
 				array( $param_info['clean'] )
 			);
 		}
-		
-		// Check for leading vertical tabs.
-		if ( preg_match( $pattern_leading_vtabs, $content_without_quotes ) ) {
+
+		// Check for leading new lines.
+		if ( preg_match( $pattern_leading_newlines, $content_without_quotes ) ) {
 			$this->phpcsFile->addError(
-				'Translatable string should not have leading vertical tabs. Found: %s',
+				'Translatable string should not have leading new lines. Found: %s',
 				$first_non_empty,
-				'LeadingVTabs',
+				'LeadingNewLines',
 				array( $param_info['clean'] )
 			);
 		}
 		
-		// Check for trailing vertical tabs.
-		if ( preg_match( $pattern_trailing_vtabs, $content_without_quotes ) ) {
+		// Check for trailing new lines.
+		if ( preg_match( $pattern_trailing_newlines, $content_without_quotes ) ) {
 			$this->phpcsFile->addError(
-				'Translatable string should not have trailing vertical tabs. Found: %s',
+				'Translatable string should not have trailing new lines. Found: %s',
 				$first_non_empty,
-				'TrailingVTabs',
+				'TrailingNewLines',
 				array( $param_info['clean'] )
 			);
 		}
diff --git a/WordPress/Tests/WP/I18nUnitTest.1.inc b/WordPress/Tests/WP/I18nUnitTest.1.inc
index fb9bdf7828..58b1e5f2da 100644
--- a/WordPress/Tests/WP/I18nUnitTest.1.inc
+++ b/WordPress/Tests/WP/I18nUnitTest.1.inc
@@ -355,6 +355,11 @@ __( 'string	', 'my-slug' ); // Bad: trailing tab.
 __( '	string	', 'my-slug' ); // Bad: leading and trailing tabs.
 __( '		string', 'my-slug' ); // Bad: two leading tabs.
 __( 'string		', 'my-slug' ); // Bad: two trailing tabs.
+__( "String with leading vertical tab", 'my-slug' ); // Bad: leading vertical tab.
+__( "String with trailing vertical tab", 'my-slug' ); // Bad: trailing vertical tab.
+__( "String with leading and trailing vertical tabs", 'my-slug' ); // Bad: leading and trailing vertical tabs.
+__( "String with 2 leading vertical tabs", 'my-slug' ); // Bad: 2 leading vertical tabs.
+__( "String with 2 trailing vertical tabs", 'my-slug' ); // Bad: 2 trailing vertical tabs.
 __( '
 string', 'my-slug' ); // Bad: leading new line.
 __( 'string
@@ -368,10 +373,5 @@ string', 'my-slug' ); // Bad: two leading new lines.
 __( 'string
 
 ', 'my-slug' ); // Bad: two trailing new lines.
-__( "String with leading vertical tab", 'my-slug' ); // Bad, has leading vertical tab.
-__( "String with trailing vertical tab", 'my-slug' ); // Bad, has trailing vertical tab.
-__( "String with leading and trailing vertical tabs", 'my-slug' ); // Bad, has both leading and trailing vertical tabs.
-__( "String with 2 leading vertical tabs", 'my-slug' ); // Bad, has 2 leading vertical tabs.
-__( "String with 2 trailing vertical tabs", 'my-slug' ); // Bad, has 2 trailing vertical tabs.
 
 // phpcs:enable WordPress.WP.I18n.MissingTranslatorsComment
diff --git a/WordPress/Tests/WP/I18nUnitTest.1.inc.fixed b/WordPress/Tests/WP/I18nUnitTest.1.inc.fixed
index 2c828c66d2..1772edf711 100644
--- a/WordPress/Tests/WP/I18nUnitTest.1.inc.fixed
+++ b/WordPress/Tests/WP/I18nUnitTest.1.inc.fixed
@@ -355,6 +355,11 @@ __( 'string	', 'my-slug' ); // Bad: trailing tab.
 __( '	string	', 'my-slug' ); // Bad: leading and trailing tabs.
 __( '		string', 'my-slug' ); // Bad: two leading tabs.
 __( 'string		', 'my-slug' ); // Bad: two trailing tabs.
+__( "String with leading vertical tab", 'my-slug' ); // Bad: leading vertical tab.
+__( "String with trailing vertical tab", 'my-slug' ); // Bad: trailing vertical tab.
+__( "String with leading and trailing vertical tabs", 'my-slug' ); // Bad: leading and trailing vertical tabs.
+__( "String with 2 leading vertical tabs", 'my-slug' ); // Bad: 2 leading vertical tabs.
+__( "String with 2 trailing vertical tabs", 'my-slug' ); // Bad: 2 trailing vertical tabs.
 __( '
 string', 'my-slug' ); // Bad: leading new line.
 __( 'string
@@ -368,10 +373,5 @@ string', 'my-slug' ); // Bad: two leading new lines.
 __( 'string
 
 ', 'my-slug' ); // Bad: two trailing new lines.
-__( "String with leading vertical tab", 'my-slug' ); // Bad, has leading vertical tab.
-__( "String with trailing vertical tab", 'my-slug' ); // Bad, has trailing vertical tab.
-__( "String with leading and trailing vertical tabs", 'my-slug' ); // Bad, has both leading and trailing vertical tabs.
-__( "String with 2 leading vertical tabs", 'my-slug' ); // Bad, has 2 leading vertical tabs.
-__( "String with 2 trailing vertical tabs", 'my-slug' ); // Bad, has 2 trailing vertical tabs.
 
 // phpcs:enable WordPress.WP.I18n.MissingTranslatorsComment
diff --git a/WordPress/Tests/WP/I18nUnitTest.php b/WordPress/Tests/WP/I18nUnitTest.php
index 0eec46cdd9..ef267e3e8d 100644
--- a/WordPress/Tests/WP/I18nUnitTest.php
+++ b/WordPress/Tests/WP/I18nUnitTest.php
@@ -177,15 +177,15 @@ public function getErrorList( $testFile = '' ) {
 					356 => 1,
 					357 => 1,
 					358 => 1,
-					360 => 1,
-					362 => 2,
+					359 => 1,
+					360 => 2,
+					361 => 1,
+					362 => 1,
+					363 => 1,
 					365 => 1,
-					368 => 1,
-					371 => 1,
-					372 => 1,
-					373 => 2,
-					374 => 1,
-					375 => 1,
+					367 => 2,
+					370 => 1,
+					373 => 1,
 				);
 
 			case 'I18nUnitTest.2.inc':

From 0f6a099daef43b4727d6449751a1762e96940c61 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jes=C3=BAs=20Amieiro?=
 <1667814+amieiro@users.noreply.github.com>
Date: Wed, 22 Apr 2026 17:58:09 +0200
Subject: [PATCH 9/9] =?UTF-8?q?=E2=99=BB=EF=B8=8F=20refactor(I18n):=20cons?=
 =?UTF-8?q?olidate=20leading/trailing=20whitespace=20check=20into=20two=20?=
 =?UTF-8?q?error=20codes?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

- replace eight per-character error codes (Leading/Trailing x Spaces/Tabs/VTabs/NewLines)
  with two generic codes: LeadingWhiteSpace and TrailingWhiteSpace
- reduce the eight hex-code regexes to a single `\s` match on each side (covers space,
  tab, vertical tab, newline, CR, form feed in one pass)
- reword error messages to use the generic term "whitespace"
- bump @since annotation from 3.2.0 to 3.4.0
- add four combination test cases (leading tab+space, trailing space+tab, mixed
  leading/trailing, multi-line with newline+tab on each side) to verify strings with
  multiple whitespace types produce at most one leading and one trailing error
---
 WordPress/Sniffs/WP/I18nSniff.php           | 93 +++------------------
 WordPress/Tests/WP/I18nUnitTest.1.inc       |  6 ++
 WordPress/Tests/WP/I18nUnitTest.1.inc.fixed |  6 ++
 WordPress/Tests/WP/I18nUnitTest.php         |  4 +
 4 files changed, 26 insertions(+), 83 deletions(-)

diff --git a/WordPress/Sniffs/WP/I18nSniff.php b/WordPress/Sniffs/WP/I18nSniff.php
index e0a96580bb..6463b7179e 100644
--- a/WordPress/Sniffs/WP/I18nSniff.php
+++ b/WordPress/Sniffs/WP/I18nSniff.php
@@ -380,7 +380,7 @@ public function process_parameters( $stackPtr, $group_name, $matched_content, $p
 				$has_content = $this->check_string_has_translatable_content( $matched_content, $param_name, $param_info );
 				if ( true === $has_content ) {
 					$this->check_string_has_no_html_wrapper( $matched_content, $param_name, $param_info );
-					$this->check_string_has_no_leading_trailing_spaces( $matched_content, $param_name, $param_info );
+					$this->check_string_has_no_leading_trailing_whitespace( $matched_content, $param_name, $param_info );
 				}
 			}
 		}
@@ -806,9 +806,9 @@ private function check_string_has_no_html_wrapper( $matched_content, $param_name
 	}
 
 	/**
-	 * Check if a translatable string has leading or trailing spaces.
+	 * Check if a translatable string has leading or trailing whitespace.
 	 *
-	 * @since 3.2.0
+	 * @since 3.4.0
 	 *
 	 * @param string      $matched_content The token content (function name) which was matched
 	 *                                     in lowercase.
@@ -818,97 +818,24 @@ private function check_string_has_no_html_wrapper( $matched_content, $param_name
 	 *
 	 * @return void
 	 */
-	private function check_string_has_no_leading_trailing_spaces( $matched_content, $param_name, $param_info ) {
-		// Strip surrounding quotes.
+	private function check_string_has_no_leading_trailing_whitespace( $matched_content, $param_name, $param_info ) {
 		$content_without_quotes = TextStrings::stripQuotes( $param_info['clean'] );
 		$first_non_empty        = $this->phpcsFile->findNext( Tokens::$emptyTokens, $param_info['start'], ( $param_info['end'] + 1 ), true );
 
-		// Define regex patterns.
-		$pattern_leading_spaces  = '/^[\x20]+/u';
-		$pattern_trailing_spaces = '/[\x20]+$/u';
-		$pattern_leading_tabs    = '/^\x09+/u';
-		$pattern_trailing_tabs   = '/\x09+$/u';
-		$pattern_leading_vtabs   = '/^\x0B+/u';
-		$pattern_trailing_vtabs  = '/\x0B+$/u';
-		$pattern_leading_newlines = '/^\x0A+/u';
-		$pattern_trailing_newlines = '/\x0A+$/u';
-
-		// Check for leading spaces.
-		if ( preg_match( $pattern_leading_spaces, $content_without_quotes ) ) {
-			$this->phpcsFile->addError(
-				'Translatable string should not have leading spaces. Found: %s',
-				$first_non_empty,
-				'LeadingSpaces',
-				array( $param_info['clean'] )
-			);
-		}
-		
-		// Check for trailing spaces.
-		if ( preg_match( $pattern_trailing_spaces, $content_without_quotes ) ) {
-			$this->phpcsFile->addError(
-				'Translatable string should not have trailing spaces. Found: %s',
-				$first_non_empty,
-				'TrailingSpaces',
-				array( $param_info['clean'] )
-			);
-		}
-		
-		// Check for leading tabs.
-		if ( preg_match( $pattern_leading_tabs, $content_without_quotes ) ) {
-			$this->phpcsFile->addError(
-				'Translatable string should not have leading tabs. Found: %s',
-				$first_non_empty,
-				'LeadingTabs',
-				array( $param_info['clean'] )
-			);
-		}
-		
-		// Check for trailing tabs.
-		if ( preg_match( $pattern_trailing_tabs, $content_without_quotes ) ) {
+		if ( preg_match( '/^\s+/u', $content_without_quotes ) ) {
 			$this->phpcsFile->addError(
-				'Translatable string should not have trailing tabs. Found: %s',
+				'Translatable string should not have leading whitespace. Found: %s',
 				$first_non_empty,
-				'TrailingTabs',
-				array( $param_info['clean'] )
-			);
-		}
-		
-		// Check for leading vertical tabs.
-		if ( preg_match( $pattern_leading_vtabs, $content_without_quotes ) ) {
-			$this->phpcsFile->addError(
-				'Translatable string should not have leading vertical tabs. Found: %s',
-				$first_non_empty,
-				'LeadingVTabs',
-				array( $param_info['clean'] )
-			);
-		}
-		
-		// Check for trailing vertical tabs.
-		if ( preg_match( $pattern_trailing_vtabs, $content_without_quotes ) ) {
-			$this->phpcsFile->addError(
-				'Translatable string should not have trailing vertical tabs. Found: %s',
-				$first_non_empty,
-				'TrailingVTabs',
+				'LeadingWhiteSpace',
 				array( $param_info['clean'] )
 			);
 		}
 
-		// Check for leading new lines.
-		if ( preg_match( $pattern_leading_newlines, $content_without_quotes ) ) {
-			$this->phpcsFile->addError(
-				'Translatable string should not have leading new lines. Found: %s',
-				$first_non_empty,
-				'LeadingNewLines',
-				array( $param_info['clean'] )
-			);
-		}
-		
-		// Check for trailing new lines.
-		if ( preg_match( $pattern_trailing_newlines, $content_without_quotes ) ) {
+		if ( preg_match( '/\s+$/u', $content_without_quotes ) ) {
 			$this->phpcsFile->addError(
-				'Translatable string should not have trailing new lines. Found: %s',
+				'Translatable string should not have trailing whitespace. Found: %s',
 				$first_non_empty,
-				'TrailingNewLines',
+				'TrailingWhiteSpace',
 				array( $param_info['clean'] )
 			);
 		}
diff --git a/WordPress/Tests/WP/I18nUnitTest.1.inc b/WordPress/Tests/WP/I18nUnitTest.1.inc
index 58b1e5f2da..0b6a694da4 100644
--- a/WordPress/Tests/WP/I18nUnitTest.1.inc
+++ b/WordPress/Tests/WP/I18nUnitTest.1.inc
@@ -373,5 +373,11 @@ string', 'my-slug' ); // Bad: two leading new lines.
 __( 'string
 
 ', 'my-slug' ); // Bad: two trailing new lines.
+__( '	 string', 'my-slug' ); // Bad: leading tab + space (1 leading whitespace error).
+__( 'string 	', 'my-slug' ); // Bad: trailing space + tab (1 trailing whitespace error).
+__( ' 	string	 ', 'my-slug' ); // Bad: mixed leading and trailing whitespace (2 errors).
+__( '
+	string
+', 'my-slug' ); // Bad: leading newline+tab and trailing tab+newline (2 errors).
 
 // phpcs:enable WordPress.WP.I18n.MissingTranslatorsComment
diff --git a/WordPress/Tests/WP/I18nUnitTest.1.inc.fixed b/WordPress/Tests/WP/I18nUnitTest.1.inc.fixed
index 1772edf711..faecf34381 100644
--- a/WordPress/Tests/WP/I18nUnitTest.1.inc.fixed
+++ b/WordPress/Tests/WP/I18nUnitTest.1.inc.fixed
@@ -373,5 +373,11 @@ string', 'my-slug' ); // Bad: two leading new lines.
 __( 'string
 
 ', 'my-slug' ); // Bad: two trailing new lines.
+__( '	 string', 'my-slug' ); // Bad: leading tab + space (1 leading whitespace error).
+__( 'string 	', 'my-slug' ); // Bad: trailing space + tab (1 trailing whitespace error).
+__( ' 	string	 ', 'my-slug' ); // Bad: mixed leading and trailing whitespace (2 errors).
+__( '
+	string
+', 'my-slug' ); // Bad: leading newline+tab and trailing tab+newline (2 errors).
 
 // phpcs:enable WordPress.WP.I18n.MissingTranslatorsComment
diff --git a/WordPress/Tests/WP/I18nUnitTest.php b/WordPress/Tests/WP/I18nUnitTest.php
index ef267e3e8d..caa037ecdf 100644
--- a/WordPress/Tests/WP/I18nUnitTest.php
+++ b/WordPress/Tests/WP/I18nUnitTest.php
@@ -186,6 +186,10 @@ public function getErrorList( $testFile = '' ) {
 					367 => 2,
 					370 => 1,
 					373 => 1,
+					376 => 1,
+					377 => 1,
+					378 => 2,
+					379 => 2,
 				);
 
 			case 'I18nUnitTest.2.inc':