19859 FIX printer_supply: skip nameless supplies during discovery

Service discovery for the printer_supply check crashed with TypeError:
'item' must be a non empty string or ommited entirely, got '' when a
printer reported a supply entry without a name.

Nameless supplies are now skipped instead of aborting discovery for the
whole device.

Crash-Group-ID: 3957
Jira: CMK-33989
Change-Id: I6830aba17ccb4b0a650d1816f71d6a4d18e51a3d

Author: otAAAh

.werks/19859.md

@@ -0,0 +1,19 @@
+[//]: # (werk v3)
+# printer_supply: skip nameless supplies during discovery
+
+key        | value
+---------- | ---
+date       | 2026-04-23T09:09:51.558507+00:00
+version    | 2.6.0b1
+class      | fix
+edition    | community
+component  | checks
+level      | 1
+compatible | yes
+
+Service discovery for the `printer_supply` check crashed with `TypeError:
+'item' must be a non empty string or ommited entirely, got ''` when a
+printer reported a supply entry without a name.
+
+Nameless supplies are now skipped instead of aborting discovery for the
+whole device.

cmk/plugins/collection/agent_based/printer_supply.py

@@ -229,6 +229,10 @@ def parse_printer_supply(string_table: Sequence[StringTable]) -> Section:
 
 def discovery_printer_supply(section: Section) -> DiscoveryResult:
     for key in section.keys():
+        # Some printers expose supply entries without a name; Service(item="")
+        # is rejected by the v2 API, so those entries are skipped.
+        if not key:
+            continue
         yield Service(item=key)
 
 

tests/unit/cmk/plugins/collection/agent_based/test_printer_supply.py

@@ -87,10 +87,6 @@ def test_inventory_printer_supply(
     assert list(result) == expected_result
 
 
-@pytest.mark.xfail(
-    strict=True,
-    reason="Crash group 3957: empty supply name crashes Service(item='')",
-)
 def test_discovery_printer_supply_skips_empty_supply_name() -> None:
     info: list[StringTable] = [
         [["1.4", "black"]],