Fix the comment, add assert.
Reported-by: Joshua Rogers
Closes #18865
*
* data [in] - The session handle.
* authzid [in] - The authorization identity if some.
- * chlg [in] - The optional challenge message.
+ * chlg [in] - The challenge message.
* krb5 [in/out] - The Kerberos 5 data struct being used and modified.
* out [out] - The result storage.
*
#endif
/* Ensure we have a valid challenge message */
+ DEBUGASSERT(chlg);
if(!Curl_bufref_len(chlg)) {
infof(data, "GSSAPI handshake failure (empty security message)");
return CURLE_BAD_CONTENT_ENCODING;