[extension/opampextension] fix self-reported status events being dropped by non-Reporter hosts

opampAgent.Start wired its internal reportFunc to call
componentstatus.ReportStatus(host, event) directly. That helper silently
no-ops when the component.Host passed to Start does not implement
componentstatus.Reporter, so self-reported status changes -- most notably
the fatal error monitorPPID emits when the collector's parent process
disappears -- never reached the extension's own status aggregator. The
collector could keep reporting healthy despite being orphaned.

Track the extension's own component.ID (added extensionID field, set from
extension.Settings.ID in newOpampAgent) and route self-reported events
through the extension's own ComponentStatusChanged handler instead, which
always forwards to the status aggregator regardless of what the host
implements.

Adds TestReportFuncReachesStatusAggregatorRegardlessOfHostReporter, which
starts the agent against componenttest.NewNopHost() (which intentionally
does not implement componentstatus.Reporter) and asserts a fatal error
event reported via o.reportFunc still reaches the mock status aggregator.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: CodeBlackwell

.chloggen/opampextension-fix-self-status-reporting.yaml

@@ -0,0 +1,29 @@
+# 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. receiver/filelog)
+component: extension/opamp
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: "Fix opampextension self-reported status events (e.g. the fatal error emitted when the parent process disappears) being silently dropped when the component.Host does not implement componentstatus.Reporter"
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [49412]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+subtext: |
+  Previously, opampAgent.Start wired its internal reportFunc to call
+  componentstatus.ReportStatus(host, event) directly. That helper is a no-op
+  when the given host does not implement componentstatus.Reporter, so
+  self-reported status changes -- most notably the fatal error monitorPPID
+  emits when the collector's parent process disappears -- were silently
+  discarded and never reached the extension's status aggregator, leaving the
+  collector reporting healthy despite being orphaned.
+
+  The extension now tracks its own component.ID and routes self-reported
+  events through its own ComponentStatusChanged handler
+  (o.ComponentStatusChanged(selfInstanceID, event)), which always forwards to
+  the status aggregator regardless of whether the host implements
+  componentstatus.Reporter.
+
+change_logs: [user]

extension/opampextension/opamp_agent.go

@@ -62,6 +62,7 @@ type opampAgent struct {
 	resourceAttrs     map[string]string
 
 	instanceUID uuid.UUID
+	extensionID component.ID
 
 	eclk            sync.RWMutex
 	effectiveConfig *confmap.Conf
@@ -106,8 +107,9 @@ var (
 )
 
 func (o *opampAgent) Start(ctx context.Context, host component.Host) error {
+	selfInstanceID := componentstatus.NewInstanceID(o.extensionID, component.KindExtension)
 	o.reportFunc = func(event *componentstatus.Event) {
-		componentstatus.ReportStatus(host, event)
+		o.ComponentStatusChanged(selfInstanceID, event)
 	}
 
 	header := http.Header{}
@@ -332,6 +334,7 @@ func newOpampAgent(cfg *Config, set extension.Settings) (*opampAgent, error) {
 		serviceVersion:           serviceVersion,
 		serviceInstanceID:        serviceInstanceID,
 		instanceUID:              uid,
+		extensionID:              set.ID,
 		capabilities:             cfg.Capabilities,
 		opampClient:              opampClient,
 		resourceAttrs:            resourceAttrs,

extension/opampextension/opamp_agent_test.go

@@ -267,6 +267,44 @@ func TestStartAvailableComponents(t *testing.T) {
 	assert.NoError(t, o.Shutdown(t.Context()))
 }
 
+// TestReportFuncReachesStatusAggregatorRegardlessOfHostReporter verifies that a
+// status reported through o.reportFunc (e.g. the fatal error monitorPPID emits when
+// the parent process disappears) always reaches the status aggregator, even when the
+// component.Host passed to Start does not implement componentstatus.Reporter. Without
+// this, PPID-orphan detection silently fails to mark the collector unhealthy.
+func TestReportFuncReachesStatusAggregatorRegardlessOfHostReporter(t *testing.T) {
+	cfg := createDefaultConfig().(*Config)
+	set := extensiontest.NewNopSettings(extensiontest.NopType)
+
+	sa := &mockStatusAggregator{mtx: &sync.RWMutex{}}
+
+	o := newTestOpampAgent(cfg, set, &mockOpAMPClient{
+		setHealthFunc: func(_ *protobufs.ComponentHealth) error { return nil },
+	}, sa)
+
+	o.initHealthReporting()
+
+	// componenttest.NewNopHost() intentionally does not implement componentstatus.Reporter.
+	require.NoError(t, o.Start(t.Context(), componenttest.NewNopHost()))
+	require.NoError(t, o.Ready())
+
+	fatalErr := errors.New("collector was orphaned")
+	o.reportFunc(componentstatus.NewFatalErrorEvent(fatalErr))
+
+	require.Eventually(t, func() bool {
+		sa.mtx.RLock()
+		defer sa.mtx.RUnlock()
+		return len(sa.receivedEvents) == 1
+	}, 5*time.Second, 100*time.Millisecond)
+
+	sa.mtx.RLock()
+	defer sa.mtx.RUnlock()
+	require.Equal(t, componentstatus.StatusFatalError, sa.receivedEvents[0].event.Status())
+	require.Equal(t, fatalErr, sa.receivedEvents[0].event.Err())
+
+	require.NoError(t, o.Shutdown(t.Context()))
+}
+
 // availableComponentsHost mocks a receiver.ReceiverHost for test purposes.
 type availableComponentsHost struct {
 	t *testing.T