1 files changed, 12 insertions, 15 deletions

diff --git a/bbot/manifest.cxx b/bbot/manifest.cxx
index 9aedcea..0f7a053 100644
--- a/bbot/manifest.cxx
+++ b/bbot/manifest.cxx
@@ -244,7 +244,7 @@ namespace bbot
       }
       else if (n == "fingerprint")
       {
-        if (!fingerprint.empty ())
+        if (fingerprint)
           bad_name ("task request fingerprint redefinition");
 
         if (!valid_sha256 (v))
@@ -261,9 +261,6 @@ namespace bbot
     if (agent.empty ())
       bad_value ("no task request agent specified");
 
-    if (fingerprint.empty ())
-      bad_value ("no task request fingerprint specified");
-
     // Parse machine header manifests.
     //
     for (nv = p.next (); !nv.empty (); nv = p.next ())
@@ -281,7 +278,10 @@ namespace bbot
     //
     s.next ("", "1"); // Start of manifest.
     s.next ("agent", agent);
-    s.next ("fingerprint", fingerprint);
+
+    if (fingerprint)
+      s.next ("fingerprint", *fingerprint);
+
     s.next ("", "");  // End of manifest.
 
     for (const machine_header_manifest& m: machines)
@@ -594,14 +594,11 @@ namespace bbot
 
     session = move (*sess);
 
-    // If session is not empty then the challenge and the result url must
-    // present, otherwise they shouldn't.
+    // If session is not empty then the challenge may, and the result url
+    // must, be present, otherwise they shouldn't.
     //
     if (!session.empty ())
     {
-      if (!challenge)
-        bad_value ("no task response challenge specified");
-
       if (!result_url)
         bad_value ("no task response result url specified");
     }
@@ -908,7 +905,7 @@ namespace bbot
       }
       else if (n == "challenge")
       {
-        if (!challenge.empty ())
+        if (challenge)
           bad_name ("result request challenge redefinition");
 
         if (v.empty ())
@@ -925,9 +922,6 @@ namespace bbot
     if (session.empty ())
       bad_value ("no result request session specified");
 
-    if (challenge.empty ())
-      bad_value ("no result request challenge specified");
-
     nv = p.next ();
     if (nv.empty ())
       bad_value ("result manifest expected");
@@ -950,7 +944,10 @@ namespace bbot
     //
     s.next ("", "1"); // Start of manifest.
     s.next ("session", session);
-    s.next ("challenge", challenge);
+
+    if (challenge)
+      s.next ("challenge", *challenge);
+
     s.next ("", ""); // End of manifest.
 
     result.serialize (s);