Clarify errors returned by serd_env_expand()

4 files changed, 15 insertions, 9 deletions

diff --git a/NEWS b/NEWS
index 101aaeea..b54e8bd4 100644
--- a/NEWS
+++ b/NEWS
@@ -1,5 +1,6 @@
 serd (0.29.3) unstable;
 
+  * Clarify errors returned by serd_env_expand()
   * Fix reported error when reading statements with only a blank node
   * Fix parsing local names that end with escaped dots
   * Add serdi option to write ASCII output
@@ -13,7 +14,7 @@ serd (0.29.3) unstable;
   * Fix building with MSVC
   * Clean up testing code
 
- -- David Robillard <d@drobilla.net>  Thu, 08 Mar 2018 15:42:51 -0500
+ -- David Robillard <d@drobilla.net>  Sun, 27 May 2018 17:51:33 +0200
 
 serd (0.28.0) stable;
 
diff --git a/serd/serd.h b/serd/serd.h
index 762c58a4..b3056239 100644
--- a/serd/serd.h
+++ b/serd/serd.h
@@ -713,6 +713,9 @@ serd_env_qualify(const SerdEnv*  env,
 
 /**
    Expand `curie`.
+
+   Errors: SERD_ERR_BAD_ARG if `curie` is not valid, or SERD_ERR_BAD_CURIE if
+   prefix is not defined in `env`.
 */
 SERD_API
 SerdStatus
@@ -723,6 +726,8 @@ serd_env_expand(const SerdEnv*  env,
 
 /**
    Expand `node`, which must be a CURIE or URI, to a full URI.
+
+   Returns null if `node` can not be expanded.
 */
 SERD_API
 SerdNode
diff --git a/src/env.c b/src/env.c
index adda27ba..d969d3df 100644
--- a/src/env.c
+++ b/src/env.c
@@ -215,8 +215,8 @@ serd_env_expand(const SerdEnv*  env,
 {
 	const uint8_t* const colon = (const uint8_t*)memchr(
 		curie->buf, ':', curie->n_bytes + 1);
-	if (!colon) {
-		return SERD_ERR_BAD_ARG;  // Invalid CURIE
+	if (curie->type != SERD_CURIE || !colon) {
+		return SERD_ERR_BAD_ARG;
 	}
 
 	const size_t            name_len = colon - curie->buf;
@@ -228,7 +228,7 @@ serd_env_expand(const SerdEnv*  env,
 		uri_suffix->len = curie->n_bytes - (colon - curie->buf) - 1;
 		return SERD_SUCCESS;
 	}
-	return SERD_ERR_NOT_FOUND;
+	return SERD_ERR_BAD_CURIE;
 }
 
 SERD_API
diff --git a/src/writer.c b/src/writer.c
index 58cf17ee..603ca65e 100644
--- a/src/writer.c
+++ b/src/writer.c
@@ -525,14 +525,14 @@ write_curie(SerdWriter* const        writer,
             const Field              field,
             const SerdStatementFlags flags)
 {
-	SerdChunk prefix;
-	SerdChunk suffix;
+	SerdChunk  prefix;
+	SerdChunk  suffix;
+	SerdStatus st;
 	switch (writer->syntax) {
 	case SERD_NTRIPLES:
 	case SERD_NQUADS:
-		if (serd_env_expand(writer->env, node, &prefix, &suffix)) {
-			w_err(writer, SERD_ERR_BAD_CURIE,
-			      "undefined namespace prefix `%s'\n", node->buf);
+		if ((st = serd_env_expand(writer->env, node, &prefix, &suffix))) {
+			w_err(writer, st, "undefined namespace prefix `%s'\n", node->buf);
 			return false;
 		}
 		write_sep(writer, SEP_URI_BEGIN);