PR#4075: taskinfo CLI and webUI info message why output is not in the list

Merges #4075
https://pagure.io/koji/pull-request/4075

Fixes: #4074
https://pagure.io/koji/issue/4074
add note that files are cleared when getTaskResults returns some results but listTaskOutput returns an empty result

cli/koji_cli/commands.py

@@ -4845,14 +4845,21 @@ def _printTaskInfo(session, task_id, topdir, level=0, recurse=True, verbose=True
         for root in buildroot_infos:
             print("%s  %s/%s-%d-%d/" %
                   (indent, BUILDDIR, root['tag_name'], root['id'], root['repo_id']))
+    print("%sLog Files:" % indent)
     if logs:
-        print("%sLog Files:" % indent)
         for log_path in logs:
             print("%s  %s" % (indent, log_path))
+    else:
+        print("%s  No outputs reported [1]" % indent)
+    print("%sOutput:" % indent)
     if output:
-        print("%sOutput:" % indent)
         for file_path in output:
             print("%s  %s" % (indent, file_path))
+    else:
+        print("%s  No outputs reported [1]" % indent)
+    if not logs or not output:
+        print("%s[1] Not all tasks produce outputs, and task outputs are not retained "
+              "indefinitely." % indent)
 
     # white space
     print('')

tests/test_cli/test_taskinfo.py

@@ -407,6 +407,11 @@ State: closed
 Created: Thu Jan  1 00:16:40 1970
 Started: Thu Jan  1 00:33:20 1970
 Finished: Thu Jan  1 00:50:00 1970
+Log Files:
+  No outputs reported [1]
+Output:
+  No outputs reported [1]
+[1] Not all tasks produce outputs, and task outputs are not retained indefinitely.
 
   Task: 2
   Type: createrepo
@@ -421,6 +426,9 @@ Finished: Thu Jan  1 00:50:00 1970
   Log Files:
     %s
     %s
+  Output:
+    No outputs reported [1]
+  [1] Not all tasks produce outputs, and task outputs are not retained indefinitely.
 
 """ % tuple('/mnt/koji/work/tasks/2/2/' + k for k in task_output.keys())
 
@@ -520,6 +528,11 @@ Started: Thu Jan  1 00:33:20 1970
 Finished: Thu Jan  1 00:50:00 1970
 Host: kojibuilder
 Build: bash-4.4.12-5.fc26 (1)
+Log Files:
+  No outputs reported [1]
+Output:
+  No outputs reported [1]
+[1] Not all tasks produce outputs, and task outputs are not retained indefinitely.
 
   Task: 2
   Type: buildArch
@@ -562,6 +575,11 @@ Build: bash-4.4.12-5.fc26 (1)
   Started: Thu Jan  1 00:33:20 1970
   Finished: Thu Jan  1 00:50:00 1970
   Host: kojibuilder
+  Log Files:
+    No outputs reported [1]
+  Output:
+    No outputs reported [1]
+  [1] Not all tasks produce outputs, and task outputs are not retained indefinitely.
 
 """
         with mock.patch('sys.stdout', new_callable=six.StringIO) as stdout:

www/kojiweb/taskinfo.chtml

@@ -269,6 +269,9 @@ $value
            #end if
         <br/>
         #end for
+        #if not $output
+            <div title="Not all tasks produce outputs, and task outputs are not retained indefinitely.">No outputs reported</div>
+        #end if
         #if $task.state not in ($koji.TASK_STATES.CLOSED, $koji.TASK_STATES.CANCELED, $koji.TASK_STATES.FAILED) and \
             $task.method in ('buildSRPMFromSCM', 'buildArch', 'createLiveMedia', 'buildMaven', 'wrapperRPM', 'vmExec', 'createrepo', 'runroot', 'createAppliance', 'createLiveCD')
         <br/>