Fix #72691: mb_ereg_search raises a warning if a match zero-width

That warning doesn't make sense (PCRE doesn't throw such a warning either),
so we remove it.

2 files changed, 48 insertions, 3 deletions

diff --git a/ext/mbstring/php_mbregex.c b/ext/mbstring/php_mbregex.c
index 67951a828e..3509165ca9 100644
--- a/ext/mbstring/php_mbregex.c
+++ b/ext/mbstring/php_mbregex.c
@@ -1235,9 +1235,6 @@ _php_mb_regex_ereg_search_exec(INTERNAL_FUNCTION_PARAMETERS, int mode)
 		php_error_docref(NULL TSRMLS_CC, E_WARNING, "mbregex search failure in mbregex_search(): %s", err_str);
 		RETVAL_FALSE;
 	} else {
-		if (MBREX(search_regs)->beg[0] == MBREX(search_regs)->end[0]) {
-			php_error_docref(NULL TSRMLS_CC, E_WARNING, "Empty regular expression");
-		}
 		switch (mode) {
 		case 1:
 			array_init(return_value);
diff --git a/ext/mbstring/tests/bug72691.phpt b/ext/mbstring/tests/bug72691.phpt
new file mode 100644
index 0000000000..d914a508e0
--- /dev/null
+++ b/ext/mbstring/tests/bug72691.phpt
@@ -0,0 +1,48 @@
+--TEST--
+Bug #72691 (mb_ereg_search raises a warning if a match zero-width)
+--SKIPIF--
+<?php
+if (!extension_loaded('mbstring')) die('skip ext/mbstring required');
+?>
+--FILE--
+<?php
+$str = 'foo';
+mb_ereg_search_init($str);
+
+mb_ereg_search('\A');
+var_dump(mb_ereg_search_getpos());
+var_dump(mb_ereg_search_getregs());
+
+mb_ereg_search('\s*');
+var_dump(mb_ereg_search_getpos());
+var_dump(mb_ereg_search_getregs());
+
+mb_ereg_search('\w+');
+var_dump(mb_ereg_search_getpos());
+var_dump(mb_ereg_search_getregs());
+
+mb_ereg_search('\Z');
+var_dump(mb_ereg_search_getpos());
+var_dump(mb_ereg_search_getregs());
+?>
+--EXPECT--
+int(1)
+array(1) {
+  [0]=>
+  string(0) ""
+}
+int(2)
+array(1) {
+  [0]=>
+  string(0) ""
+}
+int(3)
+array(1) {
+  [0]=>
+  string(1) "o"
+}
+int(4)
+array(1) {
+  [0]=>
+  string(0) ""
+}