schema parsers BUGFIX creating implicit cases when augmenting choice

In the case of an implicit case (data node in the choice is specified
without the case statement), libyang is supposed to add the case node to
avoid problems with addressing that implicit case or anything inside it
by another augments or anything else.

This fixes the bug that the implicit case was not added for the data
nodes added to a choice by augment.

Fixes #889

Author: rkrejci

src/resolve.c

@@ -4752,10 +4752,11 @@ static int
 resolve_augment(struct lys_node_augment *aug, struct lys_node *uses, struct unres_schema *unres)
 {
     int rc;
-    struct lys_node *sub;
+    struct lys_node *sub, *next;
     struct lys_module *mod;
     struct ly_set *set;
     struct ly_ctx *ctx;
+    struct lys_node_case *c;
 
     assert(aug);
     mod = lys_main_module(aug->module);
@@ -4840,6 +4841,41 @@ resolve_augment(struct lys_node_augment *aug, struct lys_node *uses, struct unre
         }
     }
 
+    if (aug->target->nodetype == LYS_CHOICE) {
+        /* in the case of implicit cases, we have to create the nodes representing them
+         * to serve as a target of the augments, they won't be printed, but they are expected in the tree */
+        LY_TREE_FOR_SAFE(aug->child, next, sub) {
+            if (sub->nodetype == LYS_CASE) {
+                /* explicit case */
+                continue;
+            }
+
+            c = calloc(1, sizeof *c);
+            LY_CHECK_ERR_RETURN(!c, LOGMEM(ctx), EXIT_FAILURE);
+            c->name = lydict_insert(ctx, sub->name, 0);
+            c->flags = LYS_IMPLICIT | (sub->flags & LYS_CONFIG_MASK);
+            c->module = sub->module;
+            c->nodetype = LYS_CASE;
+            c->parent = sub->parent;
+            c->prev = sub->prev != sub ? sub->prev : (struct lys_node*)c;
+            if (c->prev->next) {
+                c->prev->next = (struct lys_node*)c;
+            } else {
+                c->parent->child = (struct lys_node*)c;
+            }
+            c->next = sub->next;
+            if (c->next) {
+                c->next->prev = (struct lys_node*)c;
+            } else {
+                c->parent->child->prev = (struct lys_node*)c;
+            }
+            c->child = sub;
+            sub->prev = sub;
+            sub->next = NULL;
+            sub->parent = (struct lys_node*)c;
+        }
+    }
+
     if (!aug->child) {
         /* empty augment, nothing to connect, but it is techincally applied */
         LOGWRN(ctx, "Augment \"%s\" without children.", aug->target_name);

tests/data/files/defaults2.yang

@@ -2,6 +2,14 @@ module defaults2 {
     namespace "urn:defaults2";
     prefix d;
 
+    augment /d:oper/d:input/d:ch {
+      container c1 {
+        container c2 {
+          leaf l {type string;}
+        }
+      }
+    }
+
     list l1 {
         key "k";
         leaf k {
@@ -23,4 +31,10 @@ module defaults2 {
         when "/l1[k='when-true']";
         default "I exist!";
     }
+
+    rpc oper {
+      input {
+        choice ch;
+      }
+    }
 }

tests/data/test_defaults.c

@@ -456,6 +456,18 @@ test_rpc_output_default(void **state)
     assert_string_equal(st->xml, xml2);
 }
 
+static void
+test_rpc_augment(void **state)
+{
+    struct state *st = (*state);
+    const char *xml = "<oper xmlns=\"urn:defaults2\">"
+                         "<c1><c2><l>hi</l></c2></c1>"
+                       "</oper>";
+
+    st->dt = lyd_parse_mem(st->ctx, xml, LYD_XML, LYD_OPT_RPC, NULL);
+    assert_ptr_not_equal(st->dt, NULL);
+}
+
 static void
 test_notif_default(void **state)
 {
@@ -675,6 +687,7 @@ int main(void)
                     cmocka_unit_test_setup_teardown(test_df4, setup_f, teardown_f),
                     cmocka_unit_test_setup_teardown(test_rpc_input_default, setup_f, teardown_f),
                     cmocka_unit_test_setup_teardown(test_rpc_output_default, setup_f, teardown_f),
+                    cmocka_unit_test_setup_teardown(test_rpc_augment, setup_f, teardown_f),
                     cmocka_unit_test_setup_teardown(test_notif_default, setup_f, teardown_f),
                     cmocka_unit_test_setup_teardown(test_val_diff, setup_f, teardown_f),
                     cmocka_unit_test_setup_teardown(test_feature, setup_f, teardown_f),