From 99c2721738bb118c86a7ab0ed4935d7a5abe14c5 Mon Sep 17 00:00:00 2001
From: Jelle van der Waa <jvanderwaa@redhat.com>
Date: Mon, 26 Aug 2024 13:41:27 +0200
Subject: [PATCH] last fixups

---
 src/cockpit/channels/pcp.py | 16 ++++++++--------
 test/pytest/test_pcp.py     |  3 +--
 2 files changed, 9 insertions(+), 10 deletions(-)

diff --git a/src/cockpit/channels/pcp.py b/src/cockpit/channels/pcp.py
index 60344a63fdb..de775aeda34 100644
--- a/src/cockpit/channels/pcp.py
+++ b/src/cockpit/channels/pcp.py
@@ -284,7 +284,7 @@ def convert_metric_description(self, context: 'pmapi.pmContext', metric: JsonObj
         pm_units = pm_desc.units
         if units:
             try:
-                [pm_units, factor] = context.pmParseUnitsStr(units)
+                [parsed_units, factor] = context.pmParseUnitsStr(units)
             except pmapi.pmErr as exc:
                 if exc.errno() == c_api.PM_ERR_NAME:
                     raise ChannelError('not-found', message=f'no such metric: {name}') from None
@@ -293,8 +293,8 @@ def convert_metric_description(self, context: 'pmapi.pmContext', metric: JsonObj
 
             self.try_convert_unit(context, pm_desc, pm_units)
 
-            if units != pm_units or factor != 1.0:
-                units = pm_units
+            if units != parsed_units or factor != 1.0:
+                pm_units = parsed_units
 
         return MetricInfo(pmid=pm_ids[0],
                           name=name,
@@ -373,8 +373,7 @@ def send_meta(self, results: 'pmapi.pmResult', context: 'pmapi.pmContext') -> No
                         instance_desc = context.pmNameInDom(metric_desc.desc, value.inst)
                         insts.append(instance_desc)
 
-                if len(insts) > 0:
-                    desc['instances'] = insts
+                desc['instances'] = insts
 
             metrics.append(desc)
 
@@ -441,9 +440,10 @@ def sample(self, context: 'pmapi.pmContext', archive_batch: int, limit: int, tot
                         self.send_meta(results, context)
                     else:
                         if self.needs_meta_update(results):
-                            # Flush all metrics and send new meta
-                            self.send_updates(fetched)
-                            fetched.clear()
+                            # Flush all metrics and send new meta, but only if there is data
+                            if fetched:
+                                self.send_updates(fetched)
+                                fetched.clear()
                             self.send_meta(results, context)
 
                     fetched.append(self.parse_fetched_results(context, results))
diff --git a/test/pytest/test_pcp.py b/test/pytest/test_pcp.py
index 2e3eaddc053..3cf3bfc84ba 100644
--- a/test/pytest/test_pcp.py
+++ b/test/pytest/test_pcp.py
@@ -576,7 +576,6 @@ async def test_pcp_disk_metrics(transport, disk_metrics_archive):
     assert len(metrics) == 9
     network_metric = metrics[8]
     assert network_metric['name'] == 'network.interface.total.bytes'
-    assert 'instances' not in network_metric
 
     _, data = await transport.next_frame()
     data = json.loads(data)
@@ -586,7 +585,7 @@ async def test_pcp_disk_metrics(transport, disk_metrics_archive):
     meta = json.loads(data)
     network_metric = metrics[8]
     assert network_metric['name'] == 'network.interface.total.bytes'
-    assert 'instances' not in network_metric
+    assert network_metric['instances'] == []
 
     # Another meta
     assert_metrics_meta(meta, str(disk_metrics_archive), 1597663540413, 1000)