updated for version 7.4.351
Problem: sort() is not stable.
Solution: When the items are identical, compare the pointers.
diff --git a/src/eval.c b/src/eval.c
index 2aa4e54..84a798c 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -17334,6 +17334,7 @@
static char_u *item_compare_func;
static dict_T *item_compare_selfdict;
static int item_compare_func_err;
+static int item_compare_keep_zero;
static void do_sort_uniq __ARGS((typval_T *argvars, typval_T *rettv, int sort));
#define ITEM_COMPARE_FAIL 999
@@ -17374,6 +17375,12 @@
n2 = strtod((char *)p2, (char **)&p2);
res = n1 == n2 ? 0 : n1 > n2 ? 1 : -1;
}
+
+ /* When the result would be zero, compare the pointers themselves. Makes
+ * the sort stable. */
+ if (res == 0 && !item_compare_keep_zero)
+ res = s1 > s2 ? 1 : -1;
+
vim_free(tofree1);
vim_free(tofree2);
return res;
@@ -17396,7 +17403,7 @@
if (item_compare_func_err)
return 0;
- /* copy the values. This is needed to be able to set v_lock to VAR_FIXED
+ /* Copy the values. This is needed to be able to set v_lock to VAR_FIXED
* in the copy without changing the original list items. */
copy_tv(&(*(listitem_T **)s1)->li_tv, &argv[0]);
copy_tv(&(*(listitem_T **)s2)->li_tv, &argv[1]);
@@ -17415,6 +17422,12 @@
if (item_compare_func_err)
res = ITEM_COMPARE_FAIL; /* return value has wrong type */
clear_tv(&rettv);
+
+ /* When the result would be zero, compare the pointers themselves. Makes
+ * the sort stable. */
+ if (res == 0 && !item_compare_keep_zero)
+ res = s1 > s2 ? 1 : -1;
+
return res;
}
@@ -17509,6 +17522,7 @@
ptrs[i++] = li;
item_compare_func_err = FALSE;
+ item_compare_keep_zero = FALSE;
/* test the compare function */
if (item_compare_func != NULL
&& item_compare2((void *)&ptrs[0], (void *)&ptrs[1])
@@ -17536,6 +17550,7 @@
/* f_uniq(): ptrs will be a stack of items to remove */
item_compare_func_err = FALSE;
+ item_compare_keep_zero = TRUE;
item_compare_func_ptr = item_compare_func
? item_compare2 : item_compare;