patch 9.0.1416: crash when collection is modified when using filter()

Problem:    Crash when collection is modified when using filter().
Solution:   Lock the list/dict/blob. (Ernie Rael, closes #12183)

src/blob.c

@@ -592,9 +592,10 @@ blob_filter_map(
 	blob_T		*blob_arg,
 	filtermap_T	filtermap,
 	typval_T	*expr,
+	char_u		*arg_errmsg,
 	typval_T	*rettv)
 {
-    blob_T	*b;
+    blob_T	*b = blob_arg;
     int		i;
     typval_T	tv;
     varnumber_T	val;
@@ -609,7 +610,8 @@ blob_filter_map(
 	rettv->v_type = VAR_BLOB;
 	rettv->vval.v_blob = NULL;
     }
-    if ((b = blob_arg) == NULL)
+    if (b == NULL || (filtermap == FILTERMAP_FILTER
+			    && value_check_lock(b->bv_lock, arg_errmsg, TRUE)))
 	return;
 
     b_ret = b;
@@ -623,6 +625,10 @@ blob_filter_map(
     // set_vim_var_nr() doesn't set the type
     set_vim_var_type(VV_KEY, VAR_NUMBER);
 
+    int prev_lock = b->bv_lock;
+    if (b->bv_lock == 0)
+	b->bv_lock = VAR_LOCKED;
+
     // Create one funccal_T for all eval_expr_typval() calls.
     fc = eval_expr_get_funccal(expr, &newtv);
 
@@ -658,6 +664,7 @@ blob_filter_map(
 	++idx;
     }
 
+    b->bv_lock = prev_lock;
     if (fc != NULL)
 	remove_funccal();
 }

src/dict.c

@@ -1305,7 +1305,7 @@ dict_extend_func(
 	action = (char_u *)"force";
 
     if (type != NULL && check_typval_arg_type(type, &argvars[1],
-		func_name, 2) == FAIL)
+							 func_name, 2) == FAIL)
 	return;
     dict_extend(d1, d2, action, func_name);
 
@@ -1333,7 +1333,6 @@ dict_filter_map(
 	typval_T	*expr,
 	typval_T	*rettv)
 {
-    int		prev_lock;
     dict_T	*d_ret = NULL;
     hashtab_T	*ht;
     hashitem_T	*hi;
@@ -1353,8 +1352,6 @@ dict_filter_map(
 			&& value_check_lock(d->dv_lock, arg_errmsg, TRUE)))
 	return;
 
-    prev_lock = d->dv_lock;
-
     if (filtermap == FILTERMAP_MAPNEW)
     {
 	if (rettv_dict_alloc(rettv) == FAIL)
@@ -1365,7 +1362,8 @@ dict_filter_map(
     // Create one funccal_T for all eval_expr_typval() calls.
     fc = eval_expr_get_funccal(expr, &newtv);
 
-    if (filtermap != FILTERMAP_FILTER && d->dv_lock == 0)
+    int prev_lock = d->dv_lock;
+    if (d->dv_lock == 0)
 	d->dv_lock = VAR_LOCKED;
     ht = &d->dv_hashtab;
     hash_lock(ht);

src/list.c

@@ -2398,7 +2398,7 @@ list_filter_map(
     // set_vim_var_nr() doesn't set the type
     set_vim_var_type(VV_KEY, VAR_NUMBER);
 
-    if (filtermap != FILTERMAP_FILTER && l->lv_lock == 0)
+    if (l->lv_lock == 0)
 	l->lv_lock = VAR_LOCKED;
 
     // Create one funccal_T for all eval_expr_typval() calls.
@@ -2576,15 +2576,15 @@ filter_map(typval_T *argvars, typval_T *rettv, filtermap_T filtermap)
 
     if (argvars[0].v_type == VAR_DICT)
 	dict_filter_map(argvars[0].vval.v_dict, filtermap, type, func_name,
-		arg_errmsg, expr, rettv);
+						      arg_errmsg, expr, rettv);
     else if (argvars[0].v_type == VAR_BLOB)
-	blob_filter_map(argvars[0].vval.v_blob, filtermap, expr, rettv);
+	blob_filter_map(argvars[0].vval.v_blob, filtermap, expr,
+							    arg_errmsg, rettv);
     else if (argvars[0].v_type == VAR_STRING)
-	string_filter_map(tv_get_string(&argvars[0]), filtermap, expr,
+	string_filter_map(tv_get_string(&argvars[0]), filtermap, expr, rettv);
-		rettv);
     else // argvars[0].v_type == VAR_LIST
 	list_filter_map(argvars[0].vval.v_list, filtermap, type, func_name,
-		arg_errmsg, expr, rettv);
+						      arg_errmsg, expr, rettv);
 
     restore_vimvar(VV_KEY, &save_key);
     restore_vimvar(VV_VAL, &save_val);

src/proto/blob.pro

@@ -20,7 +20,7 @@ int check_blob_range(long bloblen, varnumber_T n1, varnumber_T n2, int quiet);
 int blob_set_range(blob_T *dest, long n1, long n2, typval_T *src);
 void blob_add(typval_T *argvars, typval_T *rettv);
 void blob_remove(typval_T *argvars, typval_T *rettv, char_u *arg_errmsg);
-void blob_filter_map(blob_T *blob_arg, filtermap_T filtermap, typval_T *expr, typval_T *rettv);
+void blob_filter_map(blob_T *blob_arg, filtermap_T filtermap, typval_T *expr, char_u *arg_errmsg, typval_T *rettv);
 void blob_insert_func(typval_T *argvars, typval_T *rettv);
 void blob_reduce(typval_T *argvars, typval_T *expr, typval_T *rettv);
 void blob_reverse(blob_T *b, typval_T *rettv);

src/testdir/test_filter_map.vim

@@ -116,6 +116,21 @@ func Test_map_and_modify()
   let d = #{a: 1, b: 2, c: 3}
   call assert_fails('call map(d, "remove(d, v:key)[0]")', 'E741:')
   call assert_fails('echo map(d, {k,v -> remove(d, k)})', 'E741:')
+
+  let b = 0z1234
+  call assert_fails('call filter(b, "remove(b, 0)")', 'E741:')
+endfunc
+
+func Test_filter_and_modify()
+  let l = [0]
+  " cannot change the list halfway a map()
+  call assert_fails('call filter(l, "remove(l, 0)")', 'E741:')
+
+  let d = #{a: 0, b: 0, c: 0}
+  call assert_fails('call filter(d, "remove(d, v:key)")', 'E741:')
+
+  let b = 0z1234
+  call assert_fails('call filter(b, "remove(b, 0)")', 'E741:')
 endfunc
 
 func Test_mapnew_dict()

src/version.c

@@ -695,6 +695,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1416,
 /**/
     1415,
 /**/