[Fix] Backport fix for empty files inclusion from libucl

Issue: #596
Reported by: @assistcontrol

contrib/libucl/ucl.h

@@ -107,7 +107,8 @@ typedef enum ucl_error {
 	UCL_ENESTED, /**< Input has too many recursion levels */
 	UCL_EMACRO, /**< Error processing a macro */
 	UCL_EINTERNAL, /**< Internal unclassified error */
-	UCL_ESSL /**< SSL error */
+	UCL_ESSL, /**< SSL error */
+	UCL_EMERGE /**< A merge error occured */
 } ucl_error_t;
 
 /**
@@ -1130,6 +1131,25 @@ UCL_EXTERN const ucl_object_t * ucl_parser_get_comments (struct ucl_parser *pars
 UCL_EXTERN const ucl_object_t * ucl_comments_find (const ucl_object_t *comments,
 		const ucl_object_t *srch);
 
+/**
+ * Move comment from `from` object to `to` object
+ * @param comments comments object
+ * @param what source object
+ * @param whith destination object
+ * @return `true` if `from` has comment and it has been moved to `to`
+ */
+UCL_EXTERN bool ucl_comments_move (ucl_object_t *comments,
+		const ucl_object_t *from, const ucl_object_t *to);
+
+/**
+ * Adds a new comment for an object
+ * @param comments comments object
+ * @param obj object to add comment to
+ * @param comment string representation of a comment
+ */
+UCL_EXTERN void ucl_comments_add (ucl_object_t *comments,
+		const ucl_object_t *obj, const char *comment);
+
 /**
  * Add new public key to parser for signatures check
  * @param parser parser object

contrib/libucl/ucl_parser.c

@@ -1068,6 +1068,7 @@ ucl_parser_process_object_element (struct ucl_parser *parser, ucl_object_t *nobj
 {
 	ucl_hash_t *container;
 	ucl_object_t *tobj;
+	char errmsg[256];
 
 	container = parser->stack->obj->value.ov;
 
@@ -1126,25 +1127,36 @@ ucl_parser_process_object_element (struct ucl_parser *parser, ucl_object_t *nobj
 			break;
 
 		case UCL_DUPLICATE_ERROR:
-			ucl_create_err (&parser->err, "error while parsing %s: "
-					"line: %d, column: %d: duplicate element for key '%s' "
-					"has been found",
-					parser->cur_file ? parser->cur_file : "<unknown>",
-					parser->chunks->line, parser->chunks->column, nobj->key);
+			snprintf(errmsg, sizeof(errmsg),
+					"duplicate element for key '%s' found",
+					nobj->key);
+			ucl_set_err (parser, UCL_EMERGE, errmsg, &parser->err);
 			return false;
 
 		case UCL_DUPLICATE_MERGE:
 			/*
 			 * Here we do have some old object so we just push it on top of objects stack
+			 * Check priority and then perform the merge on the remaining objects
 			 */
 			if (tobj->type == UCL_OBJECT || tobj->type == UCL_ARRAY) {
 				ucl_object_unref (nobj);
 				nobj = tobj;
 			}
-			else {
-				/* For other types we create implicit array as usual */
+			else if (priold == prinew) {
 				ucl_parser_append_elt (parser, container, tobj, nobj);
 			}
+			else if (priold > prinew) {
+				/*
+				 * We add this new object to a list of trash objects just to ensure
+				 * that it won't come to any real object
+				 * XXX: rather inefficient approach
+				 */
+				DL_APPEND (parser->trash_objs, nobj);
+			}
+			else {
+				ucl_hash_replace (container, tobj, nobj);
+				ucl_object_unref (tobj);
+			}
 			break;
 		}
 	}
@@ -2585,20 +2597,18 @@ ucl_parser_add_chunk_full (struct ucl_parser *parser, const unsigned char *data,
 		return false;
 	}
 
-	if (data == NULL) {
+	if (data == NULL && len != 0) {
 		ucl_create_err (&parser->err, "invalid chunk added");
 		return false;
 	}
-	if (len == 0) {
-		parser->top_obj = ucl_object_new_full (UCL_OBJECT, priority);
-		return true;
-	}
+
 	if (parser->state != UCL_STATE_ERROR) {
 		chunk = UCL_ALLOC (sizeof (struct ucl_chunk));
 		if (chunk == NULL) {
 			ucl_create_err (&parser->err, "cannot allocate chunk structure");
 			return false;
 		}
+
 		chunk->begin = data;
 		chunk->remain = len;
 		chunk->pos = chunk->begin;
@@ -2617,12 +2627,27 @@ ucl_parser_add_chunk_full (struct ucl_parser *parser, const unsigned char *data,
 			return false;
 		}
 
-		switch (parse_type) {
-		default:
-		case UCL_PARSE_UCL:
-			return ucl_state_machine (parser);
-		case UCL_PARSE_MSGPACK:
-			return ucl_parse_msgpack (parser);
+		if (len > 0) {
+			/* Need to parse something */
+			switch (parse_type) {
+			default:
+			case UCL_PARSE_UCL:
+				return ucl_state_machine (parser);
+			case UCL_PARSE_MSGPACK:
+				return ucl_parse_msgpack (parser);
+			}
+		}
+		else {
+			/* Just add empty chunk and go forward */
+			if (parser->top_obj == NULL) {
+				/*
+				 * In case of empty object, create one to indicate that we've
+				 * read something
+				 */
+				parser->top_obj = ucl_object_new_full (UCL_OBJECT, priority);
+			}
+
+			return true;
 		}
 	}
 

contrib/libucl/ucl_util.c

@@ -975,6 +975,7 @@ ucl_include_file_single (const unsigned char *data, size_t len,
 		if (params->soft_fail) {
 			return false;
 		}
+
 		return (!params->must_exist || false);
 	}
 
@@ -1172,11 +1173,14 @@ ucl_include_file_single (const unsigned char *data, size_t len,
 
 	res = ucl_parser_add_chunk_full (parser, buf, buflen, params->priority,
 			params->strat, params->parse_type);
-	if (!res && !params->must_exist) {
-		/* Free error */
-		utstring_free (parser->err);
-		parser->err = NULL;
-		parser->state = UCL_STATE_AFTER_VALUE;
+
+	if (!res) {
+		if (!params->must_exist) {
+			/* Free error */
+			utstring_free (parser->err);
+			parser->err = NULL;
+			res = true;
+		}
 	}
 
 	/* Stop nesting the include, take 1 level off the stack */
@@ -3450,3 +3454,39 @@ ucl_comments_find (const ucl_object_t *comments,
 
 	return NULL;
 }
+
+bool
+ucl_comments_move (ucl_object_t *comments,
+		const ucl_object_t *from, const ucl_object_t *to)
+{
+	const ucl_object_t *found;
+	ucl_object_t *obj;
+
+	if (comments && from && to) {
+		found = ucl_object_lookup_len (comments,
+				(const char *)&from, sizeof (void *));
+
+		if (found) {
+			/* Replace key */
+			obj = ucl_object_ref (found);
+			ucl_object_delete_keyl (comments, (const char *)&from,
+					sizeof (void *));
+			ucl_object_insert_key (comments, obj, (const char *)&to,
+					sizeof (void *), true);
+
+			return true;
+		}
+	}
+
+	return false;
+}
+
+void
+ucl_comments_add (ucl_object_t *comments, const ucl_object_t *obj,
+		const char *comment)
+{
+	if (comments && obj && comment) {
+		ucl_object_insert_key (comments, ucl_object_fromstring (comment),
+				(const char *)&obj, sizeof (void *), true);
+	}
+}