[Dashboard] Fix explicitInput removal

src/platform/plugins/shared/dashboard/public/dashboard_api/get_dashboard_api.ts

@@ -90,7 +90,8 @@ export function getDashboardApi({
     initialPanelsRuntimeState ?? {},
     trackPanel,
     getPanelReferences,
-    pushPanelReferences
+    pushPanelReferences,
+    savedObjectId
   );
   const dataLoadingManager = initializeDataLoadingManager(panelsManager.api.children$);
   const dataViewsManager = initializeDataViewsManager(

src/platform/plugins/shared/dashboard/public/dashboard_api/panels_manager.ts

@@ -26,6 +26,7 @@ import {
   apiPublishesUnsavedChanges,
   apiHasSerializableState,
   getTitle,
+  SerializedPanelState,
 } from '@kbn/presentation-publishing';
 import { i18n } from '@kbn/i18n';
 import { coreServices, usageCollectionService } from '../services/kibana_services';
@@ -41,14 +42,16 @@ import { arePanelLayoutsEqual } from './are_panel_layouts_equal';
 import { dashboardClonePanelActionStrings } from '../dashboard_actions/_dashboard_actions_strings';
 import { placeClonePanel } from '../panel_placement/place_clone_panel_strategy';
 import { PanelPlacementStrategy } from '../plugin_constants';
+import { getDashboardBackupService } from '../services/dashboard_backup_service';
 
 export function initializePanelsManager(
   incomingEmbeddable: EmbeddablePackageState | undefined,
   initialPanels: DashboardPanelMap,
   initialPanelsRuntimeState: UnsavedPanelState,
   trackPanel: ReturnType<typeof initializeTrackPanel>,
   getReferencesForPanelId: (id: string) => Reference[],
-  pushReferences: (references: Reference[]) => void
+  pushReferences: (references: Reference[]) => void,
+  dashboardId?: string
 ) {
   const children$ = new BehaviorSubject<{
     [key: string]: unknown;
@@ -382,11 +385,28 @@ export function initializePanelsManager(
       } => {
         const references: Reference[] = [];
 
+        const getApiMissingFallback = (id: string): SerializedPanelState<object> => {
+          // If the Dashboard has been saved with this panel before, we should be able to grab it from the current value of panels$
+          if (Object.keys(panels$.value[id].explicitInput ?? {}).length > 0) {
+            return {
+              rawState: panels$.value[id].explicitInput,
+              references: getReferencesForPanelId(id),
+            };
+          } else {
+            // otherwise, this panel may be new, and therefore will have its unsaved changes backed up in the dashboard backup service
+            return (
+              getDashboardBackupService().getSerializedPanelBackup(id, dashboardId) ?? {
+                rawState: {},
+              }
+            );
+          }
+        };
+
         const panels = Object.keys(panels$.value).reduce((acc, id) => {
           const childApi = children$.value[id];
           const serializeResult = apiHasSerializableState(childApi)
             ? childApi.serializeState()
-            : { rawState: {} };
+            : getApiMissingFallback(id);
           acc[id] = { ...panels$.value[id], explicitInput: { ...serializeResult.rawState, id } };
 
           references.push(...prefixReferencesFromPanel(id, serializeResult.references ?? []));

src/platform/plugins/shared/dashboard/public/dashboard_api/unsaved_changes_manager.ts

@@ -12,7 +12,9 @@ import { childrenUnsavedChanges$, initializeUnsavedChanges } from '@kbn/presenta
 import {
   PublishesSavedObjectId,
   PublishingSubject,
+  SerializedPanelState,
   StateComparators,
+  apiHasSerializableState,
 } from '@kbn/presentation-publishing';
 import { omit } from 'lodash';
 import { BehaviorSubject, Subject, combineLatest, debounceTime, skipWhile, switchMap } from 'rxjs';
@@ -93,17 +95,34 @@ export function initializeUnsavedChangesManager({
 
       // backup unsaved changes if configured to do so
       if (creationOptions?.useSessionStorageIntegration) {
+        const dashboardBackupService = getDashboardBackupService();
+
         // Current behaviour expects time range not to be backed up. Revisit this?
         const dashboardStateToBackup = omit(dashboardChanges ?? {}, [
           'timeRange',
           'refreshInterval',
         ]);
+
+        // TEMPORARY - back up serialized state for all panels with changes
+        if (unsavedPanelState) {
+          const serializedPanelBackup: { [key: string]: SerializedPanelState<object> } = {};
+          for (const uuid of Object.keys(unsavedPanelState)) {
+            const childApi = panelsManager.api.children$.value[uuid];
+            if (!apiHasSerializableState(childApi)) continue;
+            serializedPanelBackup[uuid] = childApi.serializeState();
+          }
+          dashboardBackupService.setSerializedPanelsBackups(
+            serializedPanelBackup,
+            savedObjectId$.value
+          );
+        }
+
         const reactEmbeddableChanges = unsavedPanelState ? { ...unsavedPanelState } : {};
         if (controlGroupChanges) {
           reactEmbeddableChanges[PANELS_CONTROL_GROUP_KEY] = controlGroupChanges;
         }
 
-        getDashboardBackupService().setState(
+        dashboardBackupService.setState(
           savedObjectId$.value,
           dashboardStateToBackup,
           reactEmbeddableChanges

src/platform/plugins/shared/dashboard/public/services/dashboard_backup_service.ts

@@ -14,7 +14,7 @@ import { i18n } from '@kbn/i18n';
 import { Storage } from '@kbn/kibana-utils-plugin/public';
 import { set } from '@kbn/safer-lodash-set';
 
-import { ViewMode } from '@kbn/presentation-publishing';
+import { SerializedPanelState, ViewMode } from '@kbn/presentation-publishing';
 import { coreServices, spacesService } from './kibana_services';
 import { DashboardState, UnsavedPanelState } from '../dashboard_api/types';
 import { DEFAULT_DASHBOARD_STATE } from '../dashboard_api/default_dashboard_state';
@@ -27,6 +27,9 @@ const DASHBOARD_VIEWMODE_LOCAL_KEY = 'dashboardViewMode';
 // this key is named `panels` for BWC reasons, but actually contains the entire dashboard state
 const DASHBOARD_STATE_SESSION_KEY = 'dashboardStateManagerPanels';
 
+// Temporary key for Dashboard to back up serialized state of all its panels
+const DASHBOARD_SERIALIZED_PANEL_BACKUP_KEY = 'dashboardSerializedPanelBackup';
+
 const getPanelsGetError = (message: string) =>
   i18n.translate('dashboard.panelStorageError.getError', {
     defaultMessage: 'Error encountered while fetching unsaved changes: {message}',
@@ -119,6 +122,32 @@ class DashboardBackupService implements DashboardBackupServiceType {
     }
   }
 
+  public getSerializedPanelBackup(panelId: string, dashboardId = DASHBOARD_PANELS_UNSAVED_ID) {
+    return this.sessionStorage.get(DASHBOARD_SERIALIZED_PANEL_BACKUP_KEY)?.[this.activeSpaceId]?.[
+      dashboardId
+    ]?.[panelId] as SerializedPanelState<object> | undefined;
+  }
+
+  public setSerializedPanelsBackups(
+    serializedPanels: { [key: string]: SerializedPanelState<object> },
+    dashboardId = DASHBOARD_PANELS_UNSAVED_ID
+  ) {
+    try {
+      const serializedPanelsBackup =
+        this.sessionStorage.get(DASHBOARD_SERIALIZED_PANEL_BACKUP_KEY) ?? {};
+      set(serializedPanelsBackup, [this.activeSpaceId, dashboardId], serializedPanels);
+      this.sessionStorage.set(DASHBOARD_SERIALIZED_PANEL_BACKUP_KEY, serializedPanelsBackup);
+    } catch (e) {
+      coreServices.notifications.toasts.addDanger({
+        title: i18n.translate('dashboard.panelStorageError.setError', {
+          defaultMessage: 'Error encountered while setting unsaved changes: {message}',
+          values: { message: e.message },
+        }),
+        'data-test-subj': 'dashboardPanelsSetFailure',
+      });
+    }
+  }
+
   public getState(id = DASHBOARD_PANELS_UNSAVED_ID) {
     try {
       const dashboardState = this.sessionStorage.get(DASHBOARD_STATE_SESSION_KEY)?.[