Code Modernization: Replace the deprecated auto_detect_line_endings setting.

Since PHP 8.1, the `auto_detect_line_endings` setting is deprecated:

> The `auto_detect_line_endings` ini setting modifies the behavior of `file()` and `fgets()` to support an isolated `\r` (as opposed to `\n` or `\r\n`) as a newline character. These newlines were used by “Classic” Mac OS, a system which has been discontinued in 2001, nearly two decades ago. Interoperability with such systems is no longer relevant.

Reference: [https://wiki.php.net/rfc/deprecations_php_8_1#auto_detect_line_endings_ini_setting PHP RFC: Deprecations for PHP 8.1: auto_detect_line_endings ini setting].

> The `auto_detect_line_endings` ini setting has been deprecated. If necessary, handle `\r` line breaks manually instead.

Reference: [https://github.com/php/php-src/blob/1cf4fb739f7a4fa8404a4c0958f13d04eae519d4/UPGRADING#L456-L457 PHP 8.1 Upgrade Notes].

This commits adds code to replace the deprecated setting and still handle old-style `\r` line-terminated files in `PO::read_line()` using `strpos()` + `fseek()`. Includes a unit test covering `\r`, `\n`, and `\r\n` line endings.

Follow-up to [51633], [51636].

Props akirk, apermo, westonruter, SergeyBiryukov.
Fixes #64928.

git-svn-id: https://develop.svn.wordpress.org/trunk@62093 602fd350-edb4-49c9-b593-d223f7449a82

Author: SergeyBiryukov

src/wp-includes/pomo/po.php

@@ -13,16 +13,6 @@
 	define( 'PO_MAX_LINE_LEN', 79 );
 }
 
-/*
- * The `auto_detect_line_endings` setting has been deprecated in PHP 8.1,
- * but will continue to work until PHP 9.0.
- * For now, we're silencing the deprecation notice as there may still be
- * translation files around which haven't been updated in a long time and
- * which still use the old MacOS standalone `\r` as a line ending.
- * This fix should be revisited when PHP 9.0 is in alpha/beta.
- */
-@ini_set( 'auto_detect_line_endings', 1 ); // phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged
-
 /**
  * Routines for working with PO files
  */
@@ -475,8 +465,31 @@ public function read_line( $f, $action = 'read' ) {
 				$use_last_line = true;
 				return true;
 			}
-			$line          = $use_last_line ? $last_line : fgets( $f );
-			$line          = ( "\r\n" === substr( $line, -2 ) ) ? rtrim( $line, "\r\n" ) . "\n" : $line;
+
+			if ( $use_last_line ) {
+				$line = $last_line;
+			} else {
+				$line = fgets( $f );
+				if ( false === $line ) {
+					return $line;
+				}
+
+				// Handle \r-only terminated lines after the deprecation of auto_detect_line_endings in PHP 8.1.
+				$r = strpos( $line, "\r" );
+				if ( false !== $r ) {
+					if ( strlen( $line ) === $r + 1
+						&& "\r\n" === substr( $line, $r )
+					) {
+						$line = rtrim( $line, "\r\n" ) . "\n";
+					} else {
+						// The lines are terminated by just \r, so we end the line there and rewind.
+						$rewind = strlen( $line ) - $r - 1;
+						$line   = substr( $line, 0, $r ) . "\n";
+						fseek( $f, - $rewind, SEEK_CUR );
+					}
+				}
+			}
+
 			$last_line     = $line;
 			$use_last_line = false;
 			return $line;

tests/phpunit/tests/pomo/po.php

@@ -338,5 +338,69 @@ public function test_import_from_file_with_windows_line_endings_should_work_as_w
 		$this->assertCount( 1, $po->entries );
 	}
 
+	/**
+	 * @ticket 64928
+	 *
+	 * @dataProvider data_import_from_file_with_various_line_endings
+	 */
+	public function test_import_from_file_with_various_line_endings( $newline, $printable_newline ) {
+		$import_file = $this->temp_filename();
+
+		$file  = 'msgid ""' . $newline;
+		$file .= 'msgstr ""' . $newline;
+		$file .= '"Project-Id-Version: WordPress 7.0\n"' . $newline;
+		$file .= '"Plural-Forms: nplurals=2; plural=n != 1;\n"';
+
+		$entries = array();
+		for ( $i = 1; $i <= 3; $i++ ) {
+			$file .= $newline;
+			$file .= $newline;
+			$line  = "Entry $i";
+			$file .= 'msgid "' . $line . '"' . $newline;
+			$file .= 'msgstr ""';
+			$entry = new Translation_Entry( array( 'singular' => $line ) );
+
+			$entries[ $entry->key() ] = $entry;
+		}
+
+		file_put_contents( $import_file, $file );
+
+		$po  = new PO();
+		$res = $po->import_from_file( $import_file );
+		unlink( $import_file );
+
+		$this->assertTrue( $res );
+
+		$this->assertSame(
+			array(
+				'Project-Id-Version' => 'WordPress 7.0',
+				'Plural-Forms'       => 'nplurals=2; plural=n != 1;',
+			),
+			$po->headers
+		);
+
+		$this->assertEquals( $po->entries, $entries, 'Failed for ' . $printable_newline );
+
+		$export_file = $this->temp_filename();
+		$po->export_to_file( $export_file );
+		$content = file_get_contents( $export_file );
+		unlink( $export_file );
+
+		$this->assertSame( str_replace( $newline, "\n", $file ), $content );
+	}
+
+	/**
+	 * Data provider.
+	 *
+	 * @return array[]
+	 */
+	public static function data_import_from_file_with_various_line_endings() {
+		return array(
+			'\r'   => array( "\r", '\r' ),
+			'\n'   => array( "\n", '\n' ),
+			'\r\n' => array( "\r\n", '\r\n' ),
+		);
+	}
+
 	// TODO: Add tests for bad files.
 }