validate: unions with leafrefs may return misleading error codes

When a leafref is not found in a union, it should not return an error
indicating the value for the leafref wouldn't match the restrictions
for a target but instead just say the leafref target wasn't found.

The only data that should indicate the error message for data type
restrictions is data associated with the target itself, not leafrefs.

Signed-off-by: Brad House <[email protected]>

Author: bradh352

src/plugins_types/union.c

@@ -150,6 +150,31 @@ lyb_parse_union(const void *lyb_data, size_t lyb_data_len, uint32_t *type_idx, c
     }
 }
 
+static void
+union_lref_error_rewrite(const struct lyd_node *ctx_node, struct ly_err_item *err, struct lysc_type *type, const void *value, size_t value_len)
+{
+    struct lysc_type_leafref *lref;
+    char *valstr = NULL;
+
+    if ((err == NULL) || (type->basetype != LY_TYPE_LEAFREF)) {
+        return;
+    }
+
+    lref = (struct lysc_type_leafref *)type;
+    free(err->apptag);
+    err->apptag = strdup("instance-required");
+
+    free(err->msg);
+
+    if (lyd_get_value(ctx_node) != NULL) {
+        valstr = strdup(lyd_get_value(ctx_node));
+    } else {
+        valstr = strndup((const char *)value, value_len);
+    }
+    asprintf(&err->msg, LY_ERRMSG_NOLREF_VAL, valstr, lyxp_get_expr(lref->path));
+    free(valstr);
+}
+
 /**
  * @brief Store (and validate) subvalue as a specific type.
  *
@@ -190,6 +215,9 @@ union_store_type(const struct ly_ctx *ctx, struct lysc_type_union *type_u, uint3
             if ((rc != LY_SUCCESS) && (rc != LY_EINCOMPLETE)) {
                 /* clear any leftover/freed garbage */
                 memset(&subvalue->value, 0, sizeof subvalue->value);
+
+                /* if this is a leafref, lets make sure we propagate the appropriate error, and not a type validation failure */
+                union_lref_error_rewrite(ctx_node, *err, type_u->types[ti], value, value_len);
                 return rc;
             }
 
@@ -228,6 +256,11 @@ union_store_type(const struct ly_ctx *ctx, struct lysc_type_union *type_u, uint3
     if ((rc != LY_SUCCESS) && (rc != LY_EINCOMPLETE)) {
         /* clear any leftover/freed garbage */
         memset(&subvalue->value, 0, sizeof subvalue->value);
+
+        /* if this is a leafref, lets make sure we propagate the appropriate error, and not a type validation failure */
+        if (type->basetype == LY_TYPE_LEAFREF) {
+            union_lref_error_rewrite(ctx_node, *err, type, value, value_len);
+        }
         return rc;
     }
 

tests/utests/types/union.c

@@ -105,8 +105,8 @@ test_data_xml(void **state)
     TEST_ERROR_XML2("",
             "defs", "", "un1", "123456789012345678901", LY_EVALID);
     CHECK_LOG_CTX("Invalid union value \"123456789012345678901\" - no matching subtype found:\n"
-            "    libyang 2 - leafref, version 1: Invalid type int8 value \"123456789012345678901\".\n"
-            "    libyang 2 - leafref, version 1: Invalid type int64 value \"123456789012345678901\".\n"
+            "    libyang 2 - leafref, version 1: Invalid leafref value \"123456789012345678901\" - no target instance \"/int8\" with the same value.\n"
+            "    libyang 2 - leafref, version 1: Invalid leafref value \"123456789012345678901\" - no target instance \"/int64\" with the same value.\n"
             "    libyang 2 - identityref, version 1: Invalid identityref \"123456789012345678901\" value - identity not found in module \"defs\".\n"
             "    libyang 2 - instance-identifier, version 1: Invalid instance-identifier \"123456789012345678901\" value - syntax error.\n"
             "    libyang 2 - string, version 1: Unsatisfied length - string \"123456789012345678901\" length is not allowed.\n",
@@ -295,7 +295,8 @@ test_validation(void **state)
     assert_int_equal(LY_EVALID, lyd_validate_all(&tree, NULL, LYD_VALIDATE_PRESENT, NULL));
     CHECK_LOG_CTX("Invalid LYB union value - no matching subtype found:\n"
             "    libyang 2 - leafref, version 1: Invalid leafref value \"one\" - no target instance \"../../a/name\" with the same value.\n"
-            "    libyang 2 - leafref, version 1: Invalid type uint32 value \"one\".\n", "/lref:test/community[name='test']/view", 0);
+            "    libyang 2 - leafref, version 1: Invalid leafref value \"one\" - no target instance \"../../b/name\" with the same value.\n",
+            "/lref:test/community[name='test']/view", 0);
 
     lyd_free_all(tree);
 }