string.c(rb_str_split_m): Handle /\K/ correctly

Use BEG(0) instead of the result of rb_reg_search to handle the cases
when the separator Regexp contains /\K/ (lookbehind) operator.

Fixes [Bug #17113]

1 files changed, 2 insertions, 1 deletions

diff --git a/string.c b/string.c
index d4ec257e87..c2cdd0051a 100644
--- a/string.c
+++ b/string.c
@@ -8216,11 +8216,12 @@ rb_str_split_m(int argc, VALUE *argv, VALUE str)
 	struct re_registers *regs;
         VALUE match = 0;
 
-        for (; (end = rb_reg_search(spat, str, start, 0)) >= 0;
+        for (; rb_reg_search(spat, str, start, 0) >= 0;
              (match ? (rb_match_unbusy(match), rb_backref_set(match)) : (void)0)) {
             match = rb_backref_get();
             if (!result) rb_match_busy(match);
             regs = RMATCH_REGS(match);
+            end = BEG(0);
 	    if (start == end && BEG(0) == END(0)) {
 		if (!ptr) {
 		    SPLIT_STR(0, 0);