backups panels show only when the asset has data

plugins/backups/plugin.py

@@ -91,7 +91,7 @@ class BackupsPlugin(BasePlugin):
         panels = [kind.infopanel() for kind in REGISTRY.values()
                   if kind.infopanel()]
         for position, kind in enumerate(REGISTRY.values()):
-            panels.append({
+            panel = {
                 'id': 'backups-{}'.format(kind.key),
                 'title': kind.displayname,
                 'assettypes': list(kind.assettypes),
@@ -105,7 +105,6 @@ class BackupsPlugin(BasePlugin):
                         {'key': 'shorthash', 'label': 'Hash', 'mono': True},
                     ],
                 },
-                'empty': kind.emptytext,
                 # The generic renderer has no per-item actions, and downloading
                 # a .reg needs a per-revision control plus a dialect choice, so
                 # the panel links to the plugin's own history view instead.
@@ -115,7 +114,16 @@ class BackupsPlugin(BasePlugin):
                     'emptylabel': 'View history',
                 },
                 'position': 40 + position,
-            })
+            }
+            # OMIT 'empty' entirely unless the kind sets it. The list renderer
+            # shows a panel when it has rows OR declares empty text, so a
+            # present-but-null 'empty' would still render the panel on every
+            # asset of the type. Most machines are not part markers and never
+            # will be, so that panel must disappear rather than announce it has
+            # nothing.
+            if kind.emptytext:
+                panel['empty'] = kind.emptytext
+            panels.append(panel)
         return panels
 
     def get_settings_defaults(self) -> List[Dict]:

plugins/backups/services/registry.py

@@ -59,8 +59,13 @@ class BackupKind:
     displayname = None
     storagebackend = 'shopdb'
     assettypes = ['*']
-    # Human note shown on the panel when there is nothing yet.
-    emptytext = 'No backups on record.'
+    # Text shown when the kind has no revisions for an asset. None means the
+    # panel HIDES entirely instead (the generic list renderer shows a panel
+    # only when it has rows or declares empty text). Default to hiding: a kind
+    # applies to an asset TYPE, but whether a given asset ever has this kind of
+    # backup is a property of the individual machine. A part marker panel on
+    # every one of 144 machines is noise, not information.
+    emptytext = None
 
     def parse(self, raw):
         """Opaque kinds return None; parseable kinds return the projection."""
@@ -118,7 +123,6 @@ class NtlarsKind(BackupKind):
     displayname = 'NTLARS / DNC Settings'
     storagebackend = 'shopdb'
     assettypes = ['machine']
-    emptytext = 'No NTLARS settings captured yet.'
 
     @staticmethod
     def embeddedmachineno(projection):
@@ -176,8 +180,10 @@ class NtlarsKind(BackupKind):
             'title': 'DNC Info',
             'assettypes': ['machine'],
             'endpoint': '/api/backups/asset/{assetid}/info?kind=ntlars',
+            # No 'empty' key: the keyvalue renderer decides visibility purely on
+            # field count and never displays empty text, so a machine with no
+            # NTLARS revision simply has no DNC Info card at all.
             'render': 'keyvalue',
-            'empty': 'No NTLARS settings captured for this machine yet.',
             # Above the history panels: this answers the question a tech
             # arrives with, while history is for the rarer restore case.
             'position': 38,
@@ -214,7 +220,6 @@ class PartMarkerKind(BackupKind):
     displayname = 'Part Marker Configuration'
     storagebackend = 'share'
     assettypes = ['machine', 'measuring_tool']
-    emptytext = 'No part marker backups on record.'
 
     def resolveassetid(self, payload):
         from shopdb.api import db, Asset