patch 8.2.4627: flatten() does not use maxdepth correctly

Problem:    flatten() does not use maxdepth correctly.
Solution:   Use a recursive implementation. (closes #10020)

diff --git a/src/list.c b/src/list.c
index 88f3102530fac781df7e4201d36cb9fdb104a0a9..9309048174572449b4cfc5b514d16b0b61a8468d 100644 (file)
--- a/src/list.c
+++ b/src/list.c
@@ -916,35 +916,40 @@ list_assign_range(
 }
 
 /*
- * Flatten "list" to depth "maxdepth".
+ * Flatten up to "maxitems" in "list", starting at "first" to depth "maxdepth".
+ * When "first" is NULL use the first item.
  * It does nothing if "maxdepth" is 0.
  * Returns FAIL when out of memory.
  */
     static void
-list_flatten(list_T *list, long maxdepth)
+list_flatten(list_T *list, listitem_T *first, long maxitems, long maxdepth)
 {
     listitem_T *item;
     listitem_T *tofree;
-    int                n;
+    int                done = 0;
 
     if (maxdepth == 0)
        return;
     CHECK_LIST_MATERIALIZE(list);
+    if (first == NULL)
+       item = list->lv_first;
+    else
+       item = first;
 
-    n = 0;
-    item = list->lv_first;
-    while (item != NULL)
+    while (item != NULL && done < maxitems)
     {
+       listitem_T      *next = item->li_next;
+
        fast_breakcheck();
        if (got_int)
            return;
 
        if (item->li_tv.v_type == VAR_LIST)
        {
-           listitem_T *next = item->li_next;
+           list_T      *itemlist = item->li_tv.vval.v_list;
 
            vimlist_remove(list, item, item);
-           if (list_extend(list, item->li_tv.vval.v_list, next) == FAIL)
+           if (list_extend(list, itemlist, next) == FAIL)
            {
                list_free_item(list, item);
                return;
@@ -952,23 +957,15 @@ list_flatten(list_T *list, long maxdepth)
            clear_tv(&item->li_tv);
            tofree = item;
 
-           if (item->li_prev == NULL)
-               item = list->lv_first;
-           else
-               item = item->li_prev->li_next;
+           if (maxdepth > 0)
+               list_flatten(list, item->li_prev == NULL
+                                    ? list->lv_first : item->li_prev->li_next,
+                               itemlist->lv_len, maxdepth - 1);
            list_free_item(list, tofree);
-
-           if (++n >= maxdepth)
-           {
-               n = 0;
-               item = next;
-           }
-       }
-       else
-       {
-           n = 0;
-           item = item->li_next;
        }
+
+       ++done;
+       item = next;
     }
 }
 
@@ -1031,7 +1028,7 @@ flatten_common(typval_T *argvars, typval_T *rettv, int make_copy)
        ++l->lv_refcount;
     }
 
-    list_flatten(l, maxdepth);
+    list_flatten(l, NULL, l->lv_len, maxdepth);
 }
 
 /*

diff --git a/src/testdir/test_flatten.vim b/src/testdir/test_flatten.vim
index 4edf0e0dbba9c3efd0f2d0161afbf0adf38952c2..a79014de5a8eced52c49a066f55ccd5a0aa20a31 100644 (file)
--- a/src/testdir/test_flatten.vim
+++ b/src/testdir/test_flatten.vim
@@ -79,6 +79,14 @@ func Test_flatten()
   call add(y, x) " l:y = [2, [1, [...]]]
   call assert_equal([1, 2, 1, 2], flatten(l:x, 2))
   call assert_equal([2, l:x], l:y)
+
+  let l4 = [ 1, [ 11, [ 101, [ 1001 ] ] ] ]
+  call assert_equal(l4, flatten(deepcopy(l4), 0))
+  call assert_equal([1, 11, [101, [1001]]], flatten(deepcopy(l4), 1))
+  call assert_equal([1, 11, 101, [1001]], flatten(deepcopy(l4), 2))
+  call assert_equal([1, 11, 101, 1001], flatten(deepcopy(l4), 3))
+  call assert_equal([1, 11, 101, 1001], flatten(deepcopy(l4), 4))
+  call assert_equal([1, 11, 101, 1001], flatten(deepcopy(l4)))
 endfunc
 
 func Test_flattennew()
@@ -88,6 +96,14 @@ func Test_flattennew()
 
   call assert_equal([1, 2, [3, 4], 5], flattennew(l, 1))
   call assert_equal([1, [2, [3, 4]], 5], l)
+
+  let l4 = [ 1, [ 11, [ 101, [ 1001 ] ] ] ]
+  call assert_equal(l4, flatten(deepcopy(l4), 0))
+  call assert_equal([1, 11, [101, [1001]]], flattennew(l4, 1))
+  call assert_equal([1, 11, 101, [1001]], flattennew(l4, 2))
+  call assert_equal([1, 11, 101, 1001], flattennew(l4, 3))
+  call assert_equal([1, 11, 101, 1001], flattennew(l4, 4))
+  call assert_equal([1, 11, 101, 1001], flattennew(l4))
 endfunc
 
 " vim: shiftwidth=2 sts=2 expandtab

diff --git a/src/version.c b/src/version.c
index c13d03f2cccabec374a594dab7f980520d2c8473..e292626a86bb545c606ccc38197800c317da8fee 100644 (file)
--- a/src/version.c
+++ b/src/version.c
@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    4627,
 /**/
     4626,
 /**/