Fix rooted relative URI serialisation

2 files changed, 14 insertions, 5 deletions

diff --git a/src/uri.c b/src/uri.c
index b254bea6..096a45e4 100644
--- a/src/uri.c
+++ b/src/uri.c
@@ -437,8 +437,10 @@ serd_uri_serialise_relative(const SerdURI* uri,
                             SerdSink       sink,
                             void*          stream)
 {
-	size_t     len      = 0;
-	const bool relative = uri_is_under(uri, root ? root : base);
+	size_t     len = 0;
+	const bool relative =
+		root ? uri_is_under(uri, root) : uri_is_related(uri, base);
+
 	if (relative) {
 		len = write_rel_path(sink, stream, uri, base);
 	}
diff --git a/src/uri_utils.h b/src/uri_utils.h
index a22bc7bf..bf5ec3d9 100644
--- a/src/uri_utils.h
+++ b/src/uri_utils.h
@@ -44,11 +44,11 @@ uri_path_at(const SerdURI* uri, size_t i)
 	}
 }
 
-/** Return true iff `uri` is within the base of `root` */
+/** Return true iff `uri` shares path components with `root` */
 static inline bool
-uri_is_under(const SerdURI* uri, const SerdURI* root)
+uri_is_related(const SerdURI* uri, const SerdURI* root)
 {
-	if (!root || !root->scheme.len ||
+	if (!root || !root->scheme.len || uri->path.len == 1 ||
 	    !slice_equals(&root->scheme, &uri->scheme) ||
 	    !slice_equals(&root->authority, &uri->authority)) {
 		return false;
@@ -69,6 +69,13 @@ uri_is_under(const SerdURI* uri, const SerdURI* root)
 	return true;
 }
 
+/** Return true iff `uri` is within the base of `root` */
+static inline bool
+uri_is_under(const SerdURI* uri, const SerdURI* root)
+{
+	return uri->path.len >= root->path.len && uri_is_related(uri, root);
+}
+
 static inline bool
 is_uri_scheme_char(const uint8_t c)
 {