Array#sort_by! return early if sorting is useless

`Array#sort!` does that check, but `#sort_by!` always tries to
sort, which is wasteful.

1 files changed, 4 insertions, 2 deletions

diff --git a/array.c b/array.c
index e799c2f4e5..7ba887dc89 100644
--- a/array.c
+++ b/array.c
@@ -3607,8 +3607,10 @@ rb_ary_sort_by_bang(VALUE ary)
 
     RETURN_SIZED_ENUMERATOR(ary, 0, 0, ary_enum_length);
     rb_ary_modify(ary);
-    sorted = rb_block_call(ary, rb_intern("sort_by"), 0, 0, sort_by_i, 0);
-    rb_ary_replace(ary, sorted);
+    if (RARRAY_LEN(ary) > 1) {
+        sorted = rb_block_call(ary, rb_intern("sort_by"), 0, 0, sort_by_i, 0);
+        rb_ary_replace(ary, sorted);
+    }
     return ary;
 }