From e969a82bd8b0461120544b76941741f3b0551620 Mon Sep 17 00:00:00 2001
From: missusk <missusk@protonmail.com>
Date: Fri, 28 Aug 2026 21:38:23 +0530
Subject: [PATCH] Preserve whitespace in array settings

---
 tests/php/smoke/WpscCacheSettingTest.php | 60 ++++++++++++++++++++++++
 wp-cache-phase2.php                      | 50 +++++++++++++++++++-
 2 files changed, 108 insertions(+), 2 deletions(-)

diff --git a/tests/php/smoke/WpscCacheSettingTest.php b/tests/php/smoke/WpscCacheSettingTest.php
index ba37b65d..717d566a 100644
--- a/tests/php/smoke/WpscCacheSettingTest.php
+++ b/tests/php/smoke/WpscCacheSettingTest.php
@@ -151,6 +151,66 @@ public function test_value_round_trips( string $value ): void {
 		$this->assertSame( $value, $this->read_back() );
 	}
 
+	/** Array values must preserve whitespace inside every string element. */
+	public function test_array_value_round_trips_internal_whitespace(): void {
+		$value = array(
+			'double space'       => 'Mozilla  Foo',
+			'tab'                => "a\tb",
+			'newlines'           => "one\ntwo\r\nthree",
+			'trailing backslash' => 'C:\\cache\\',
+			'escape sequence'    => '\' . "\n" . \'',
+			'nested'             => array( 'mixed' => "left\t  right" ),
+		);
+
+		wp_cache_setting( self::FIELD, $value );
+
+		$this->assertSame( $value, $this->read_back() );
+	}
+
+	/** Array values containing newlines must still occupy one physical line. */
+	public function test_array_value_with_newlines_is_written_on_one_line(): void {
+		$before = count( file( $GLOBALS['wp_cache_config_file'] ) );
+		$value  = array( 'line endings' => "one\ntwo\r\nthree" );
+
+		wp_cache_setting( self::FIELD, $value );
+
+		$this->assertCount(
+			$before,
+			file( $GLOBALS['wp_cache_config_file'] ),
+			'The array value was written across more than one physical line.'
+		);
+		$this->assertSame( $value, $this->read_back() );
+	}
+
+	/** Rewriting an array containing newlines must leave the file parseable. */
+	public function test_overwriting_array_with_newlines_leaves_the_file_parseable(): void {
+		wp_cache_setting( self::FIELD, array( 'multiline' => "one\ntwo" ) );
+		wp_cache_setting( self::FIELD, array( 'plain' => 'value' ) );
+
+		$this->assertSame( array( 'plain' => 'value' ), $this->read_back() );
+	}
+
+	/** Array elements cannot end their string literal and inject a statement. */
+	public function test_array_value_cannot_smuggle_a_statement(): void {
+		$value = array( "/var/www/cache/';\$GLOBALS['wpsc_config_side_effect'] = true;" );
+
+		wp_cache_setting( self::FIELD, $value );
+		$written = $this->read_back();
+
+		$this->assertArrayNotHasKey( 'wpsc_config_side_effect', $GLOBALS );
+		$this->assertSame( $value, $written );
+	}
+
+	/** Ordinary arrays keep their existing compact source representation. */
+	public function test_ordinary_array_value_is_written_unchanged(): void {
+		wp_cache_setting( self::FIELD, array( 'one', 'two' ) );
+
+		$this->assertStringContainsString(
+			'$' . self::FIELD . " = array ( 0 => 'one', 1 => 'two', );",
+			file_get_contents( $GLOBALS['wp_cache_config_file'] )
+		);
+	}
+
 	/**
 	 * The entry must occupy exactly one physical line whatever the value holds.
 	 *
diff --git a/wp-cache-phase2.php b/wp-cache-phase2.php
index 9d01d798..b969b7b7 100644
--- a/wp-cache-phase2.php
+++ b/wp-cache-phase2.php
@@ -1673,6 +1673,53 @@ function is_writeable_ACLSafe( $path ) {
 	return true;
 }
 
+/**
+ * Export a value as PHP source that occupies one physical line.
+ *
+ * @param mixed $value Value to export.
+ * @return string Exported PHP source.
+ */
+function wpsc_var_export_one_line( $value ) {
+	// phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_var_export -- Generating PHP source for the config file, which is what var_export() is for.
+	$exported  = var_export( $value, true );
+	$one_line  = '';
+	$in_string = false;
+	$escaped   = false;
+	$length    = strlen( $exported );
+
+	for ( $i = 0; $i < $length; ++$i ) {
+		$character = $exported[ $i ];
+
+		if ( ! $in_string && ( ' ' === $character || "\t" === $character || "\r" === $character || "\n" === $character ) ) {
+			if ( '' !== $one_line && ' ' !== $one_line[ strlen( $one_line ) - 1 ] ) {
+				$one_line .= ' ';
+			}
+			continue;
+		}
+
+		if ( "\r" === $character || "\n" === $character ) {
+			$one_line .= "\r" === $character ? '\' . "\r" . \'' : '\' . "\n" . \'';
+			$escaped   = false;
+			continue;
+		}
+
+		$one_line .= $character;
+
+		if ( ! $in_string ) {
+			$in_string = "'" === $character;
+			continue;
+		}
+
+		if ( "'" === $character && ! $escaped ) {
+			$in_string = false;
+		}
+
+		$escaped = '\\' === $character ? ! $escaped : false;
+	}
+
+	return $one_line;
+}
+
 function wp_cache_setting( $field, $value ) {
 	global $wp_cache_config_file;
 
@@ -1683,8 +1730,7 @@ function wp_cache_setting( $field, $value ) {
 		$output_value = $value === true ? 'true' : 'false';
 		return wp_cache_replace_line( '^ *\$' . $field, "\$$field = $output_value;", $wp_cache_config_file );
 	} elseif ( is_object( $value ) || is_array( $value ) ) {
-		$text = var_export( $value, true );
-		$text = preg_replace( '/[\s]+/', ' ', $text );
+		$text = wpsc_var_export_one_line( $value );
 		return wp_cache_replace_line( '^ *\$' . $field, "\$$field = $text;", $wp_cache_config_file );
 	} else {
 		/*