Fix GH-8561 and GH-8562

These bugs need a header change, and thus are an ABI break

Author: Girgias

ext/spl/spl_directory.c

@@ -2047,10 +2047,12 @@ static void spl_filesystem_file_rewind(zval * this_ptr, spl_filesystem_object *i
 	}
 	if (-1 == php_stream_rewind(intern->u.file.stream)) {
 		zend_throw_exception_ex(spl_ce_RuntimeException, 0, "Cannot rewind file %s", ZSTR_VAL(intern->file_name));
-	} else {
-		spl_filesystem_file_free_line(intern);
-		intern->u.file.current_line_num = 0;
+		return;
 	}
+
+	spl_filesystem_file_free_line(intern);
+	intern->u.file.current_line_num = 0;
+	intern->u.file.lines_to_catch_up = 0;
 	if (SPL_HAS_FLAG(intern->flags, SPL_FILE_OBJECT_READ_AHEAD)) {
 		spl_filesystem_file_read_line(this_ptr, intern, /* silent */ true);
 	}
@@ -2191,6 +2193,8 @@ PHP_METHOD(SplFileObject, fgets)
 	if (spl_filesystem_file_read_ex(intern, /* silent */ false, /* line_add */ 1) == FAILURE) {
 		RETURN_THROWS();
 	}
+	/* Inform current() that it needs to catch up a line */
+	intern->u.file.lines_to_catch_up++;
 	RETURN_STRINGL(intern->u.file.current_line, intern->u.file.current_line_len);
 } /* }}} */
 
@@ -2205,9 +2209,19 @@ PHP_METHOD(SplFileObject, current)
 
 	CHECK_SPL_FILE_OBJECT_IS_INITIALIZED(intern);
 
+	/* No lines have been read yet (rewind or just opened file) */
 	if (!intern->u.file.current_line && Z_ISUNDEF(intern->u.file.current_zval)) {
 		spl_filesystem_file_read_line(ZEND_THIS, intern, /* silent */ true);
 	}
+	/* next() of fgets() has been called and we need to read the line which is now pointed at */
+	if (intern->u.file.lines_to_catch_up > 0) {
+		ZEND_ASSERT(intern->u.file.current_line || !Z_ISUNDEF(intern->u.file.current_zval));
+		for (; 0 < intern->u.file.lines_to_catch_up; intern->u.file.lines_to_catch_up--) {
+			/* Free fetched line */
+			spl_filesystem_file_free_line(intern);
+			spl_filesystem_file_read_line(ZEND_THIS, intern, /* silent */ true);
+		}
+	}
 	if (intern->u.file.current_line && (!SPL_HAS_FLAG(intern->flags, SPL_FILE_OBJECT_READ_CSV) || Z_ISUNDEF(intern->u.file.current_zval))) {
 		RETURN_STRINGL(intern->u.file.current_line, intern->u.file.current_line_len);
 	} else if (!Z_ISUNDEF(intern->u.file.current_zval)) {
@@ -2242,9 +2256,11 @@ PHP_METHOD(SplFileObject, next)
 		RETURN_THROWS();
 	}
 
-	spl_filesystem_file_free_line(intern);
 	if (SPL_HAS_FLAG(intern->flags, SPL_FILE_OBJECT_READ_AHEAD)) {
+		spl_filesystem_file_free_line(intern);
 		spl_filesystem_file_read_line(ZEND_THIS, intern, /* silent */ true);
+	} else {
+		intern->u.file.lines_to_catch_up++;
 	}
 	intern->u.file.current_line_num++;
 } /* }}} */

ext/spl/spl_directory.h

@@ -85,7 +85,8 @@ struct _spl_filesystem_object {
 			char               *current_line;
 			size_t             current_line_len;
 			size_t             max_line_len;
-			zend_long               current_line_num;
+			zend_long          current_line_num;
+			zend_long          lines_to_catch_up;
 			zval               zresource;
 			zend_function      *func_getCurr;
 			char               delimiter;

ext/spl/tests/SplFileObject/gh8561.phpt

@@ -0,0 +1,22 @@
+--TEST--
+Bug GH-8561: SplFileObject: key() and current() unsinchronized after call to fgets()
+--FILE--
+<?php
+$file = new SplTempFileObject();
+
+// write to file
+for ($i = 0; $i < 5; $i++) {
+    $file->fwrite("line {$i}" . PHP_EOL);
+}
+
+$file->rewind();
+
+// read first line
+$file->fgets();
+
+// where am I?
+echo $file->key(), ': ', $file->current();
+
+?>
+--EXPECT--
+1: line 1

ext/spl/tests/SplFileObject/gh8562.phpt

@@ -0,0 +1,22 @@
+--TEST--
+Bug GH-8562: SplFileObject: current() returns wrong result after call to next()
+--FILE--
+<?php
+$file = new SplTempFileObject();
+
+// write to file
+for ($i = 0; $i < 5; $i++) {
+    $file->fwrite("line {$i}" . PHP_EOL);
+}
+
+$file->rewind();
+
+$file->next();
+echo $file->key(), ': ', $file->current();
+$file->next();
+echo $file->key(), ': ', $file->current();
+
+?>
+--EXPECT--
+1: line 1
+2: line 2