avoid reporting empty version_info for components that just started

Given a design choice, the coordinator's reported state might be stale, leading to healthy components lacking version_info. 
The state diagnostics hook now re-fetches once the state when necessary, improving the accuracy of component status reporting.

internal/pkg/agent/application/coordinator/coordinator.go

@@ -426,7 +426,8 @@ func New(logger *logger.Logger, cfg *configuration.Configuration, logLevel logp.
 	return c
 }
 
-// State returns the current state for the coordinator.
+// State returns the current state for the coordinator. It might be a state
+// behind the actual state. See broadcaster.New for details.
 // Called by external goroutines.
 func (c *Coordinator) State() State {
 	return c.stateBroadcaster.Get()
@@ -904,15 +905,35 @@ func (c *Coordinator) DiagnosticHooks() diagnostics.Hooks {
 					UpgradeDetails *details.Details       `yaml:"upgrade_details,omitempty"`
 				}
 
-				s := c.State()
-				n := len(s.Components)
-				compStates := make([]StateComponentOutput, n)
-				for i := 0; i < n; i++ {
-					compStates[i] = StateComponentOutput{
-						ID:    s.Components[i].Component.ID,
-						State: s.Components[i].State,
+				getState := func(c *Coordinator) (State, []StateComponentOutput) {
+					s := c.State()
+					compStates := make([]StateComponentOutput, len(s.Components))
+					for i, comp := range s.Components {
+						compStates[i] = StateComponentOutput{
+							ID:    comp.Component.ID,
+							State: comp.State,
+						}
+					}
+					return s, compStates
+				}
+				s, compStates := getState(c)
+
+				// c.State() may return a stale state (up to 1 version behind)
+				// due to potential delays in state updates.
+				// If the state is HEALTH but `version_info` is missing, it
+				// indicates staleness.
+				// In this case, the state is re-fetched to obtain the latest
+				// information. After the second fetch, no more checks are
+				// performed and the state is returned as is.
+				for _, cs := range compStates {
+					if cs.State.State == client.UnitStateStarting ||
+						(cs.State.VersionInfo.BuildHash == "" ||
+							cs.State.VersionInfo.Meta["commit"] == "") {
+						s, compStates = getState(c)
+						break
 					}
 				}
+
 				output := StateHookOutput{
 					State:          s.State,
 					Message:        s.Message,

internal/pkg/agent/application/coordinator/diagnostics_test.go

@@ -412,7 +412,7 @@ components:
 // the state diagnostic reports it.
 func TestDiagnosticState(t *testing.T) {
 	now := time.Now().UTC()
-	state := State{
+	state1 := State{
 		State:        agentclient.Starting,
 		Message:      "starting up",
 		FleetState:   agentclient.Configuring,
@@ -422,11 +422,12 @@ func TestDiagnosticState(t *testing.T) {
 			{
 				Component: component.Component{ID: "comp-1"},
 				State: runtime.ComponentState{
-					State:   client.UnitStateDegraded,
-					Message: "degraded message",
+					State:   client.UnitStateStarting,
+					Message: "starting message",
 					VersionInfo: runtime.ComponentVersionInfo{
 						Name:      "version name",
 						BuildHash: "a-build-hash",
+						Meta:      map[string]string{},
 					},
 				},
 			},
@@ -444,6 +445,9 @@ func TestDiagnosticState(t *testing.T) {
 		},
 	}
 
+	state2 := state1
+	state2.Components[0].State.VersionInfo.Meta["commit"] = "a-commit-hash"
+
 	expected := fmt.Sprintf(`
 state: 0
 message: "starting up"
@@ -454,14 +458,16 @@ components:
   - id: "comp-1"
     state:
       pid: 0
-      state: 3
-      message: "degraded message"
+      state: 0
+      message: "starting message"
       features_idx: 0
       component_idx: 0
       units: {}
       version_info:
         name: "version name"
         build_hash: "a-build-hash"
+        meta:
+          commit: "a-commit-hash"
 upgrade_details:
   target_version: 8.12.0
   state: UPG_DOWNLOADING
@@ -476,9 +482,10 @@ upgrade_details:
 	coord := &Coordinator{
 		// This test needs a broadcaster since the components-actual diagnostic
 		// fetches the state via State().
-		stateBroadcaster: broadcaster.New(state, 0, 0),
+		stateBroadcaster: broadcaster.New(state1, 0, 0),
 	}
 
+	coord.stateBroadcaster.InputChan <- state2
 	hook, ok := diagnosticHooksMap(coord)["state"]
 	require.True(t, ok, "diagnostic hooks should have an entry for state")