[chore] Fix failing test case for flinkmetrics (open-telemetry#23143)

On failure to read job metrics, this type can be nil causing a panic.

.chloggen/msg_hotfix-flinkmetrics.yaml

@@ -0,0 +1,20 @@
+# Use this changelog template to create an entry for release notes.
+# If your change doesn't affect end users, such as a test fix or a tooling change,
+# you should instead start your pull request title with [chore] or use the "Skip Changelog" label.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: bug_fix
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: flink metrics receiver
+
+# A brief description of the change. Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Fixed error when failing to read job manager metrics
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [23143]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:

receiver/flinkmetricsreceiver/process.go

@@ -13,6 +13,9 @@ import (
 )
 
 func (s *flinkmetricsScraper) processJobmanagerMetrics(now pcommon.Timestamp, jobmanagerMetrics *models.JobmanagerMetrics) {
+ if jobmanagerMetrics == nil {
+ return
+ }
  for _, metric := range jobmanagerMetrics.Metrics {
  switch metric.ID {
  case "Status.JVM.CPU.Load":