Always prioritize running actions over scheduled actions in UI

Previously it was possible, especially in the short UI, that the oldest
action bazel chose to display was scheduled, even though there were
newer actions that were running. Now running actions are always
prioritized even if they're newer.

Fixes #25235

Author: keith

src/main/java/com/google/devtools/build/lib/runtime/UiStateTracker.java

@@ -913,16 +913,27 @@ protected String describeAction(
     return prefix + message + postfix;
   }
 
-  protected ActionState getOldestAction() {
-    long minStart = Long.MAX_VALUE;
-    ActionState result = null;
+  private ActionState getOldestAction() {
+    long minRunningStart = Long.MAX_VALUE;
+    ActionState oldestRunning = null;
+    long minScheduledStart = Long.MAX_VALUE;
+    ActionState oldestScheduled = null;
+
     for (ActionState action : activeActions.values()) {
-      if (action.nanoStartTime < minStart) {
-        minStart = action.nanoStartTime;
-        result = action;
+      if (action.getPhase().equals(ActionPhase.RUNNING)) {
+        if (action.nanoStartTime < minRunningStart) {
+          minRunningStart = action.nanoStartTime;
+          oldestRunning = action;
+        }
+      } else {
+        if (action.nanoStartTime < minScheduledStart) {
+          minScheduledStart = action.nanoStartTime;
+          oldestScheduled = action;
+        }
       }
     }
-    return result;
+
+    return oldestRunning != null ? oldestRunning : oldestScheduled;
   }
 
   protected String countActions() {

src/test/java/com/google/devtools/build/lib/runtime/UiStateTrackerTest.java

@@ -1706,4 +1706,30 @@ public void testTestAnalyzedEvent_repeated_noDuplicatedCount() throws Exception
     output = terminalWriter.getTranscript();
     assertThat(output).contains(" 1 / 1 tests");
   }
+
+  @Test
+  public void testGetOldestAction_prioritizesRunningOverScheduled() throws Exception {
+    ManualClock clock = new ManualClock();
+    UiStateTracker stateTracker = getUiStateTracker(clock);
+    simulateExecutionPhase(stateTracker);
+
+    Action scheduledAction = mockAction("Scheduled action", "scheduled/action");
+    when(scheduledAction.getOwner()).thenReturn(dummyActionOwner());
+    stateTracker.actionStarted(new ActionStartedEvent(scheduledAction, clock.nanoTime()));
+    stateTracker.schedulingAction(new SchedulingActionEvent(scheduledAction, "some-strategy"));
+
+    clock.advanceMillis(1000);
+    Action runningAction = mockAction("Running action", "running/action");
+    when(runningAction.getOwner()).thenReturn(dummyActionOwner());
+    stateTracker.actionStarted(new ActionStartedEvent(runningAction, clock.nanoTime()));
+    stateTracker.runningAction(new RunningActionEvent(runningAction, "some-strategy"));
+
+    LoggingTerminalWriter terminalWriter = new LoggingTerminalWriter(/* discardHighlight= */ true);
+    stateTracker.writeProgressBar(terminalWriter, /*shortVersion= */true);
+    String output = terminalWriter.getTranscript();
+
+    assertThat(output).contains("Running action");
+    assertThat(output).contains("(2 actions, 1 running)");
+    assertThat(output).doesNotContain("Scheduled action");
+  }
 }