From f34c19717db0d3c2138defdc848f04dff5b9262a Mon Sep 17 00:00:00 2001
From: Art Lowel <art@atmire.com>
Date: Wed, 15 May 2019 10:51:36 +0200
Subject: [PATCH] fix an issue where the state of an aggregated RD would be
 wrong when some of the RDs it's based on were still pending

---
 .../builders/remote-data-build.service.ts     | 26 ++++++++++++++-----
 1 file changed, 19 insertions(+), 7 deletions(-)

diff --git a/src/app/core/cache/builders/remote-data-build.service.ts b/src/app/core/cache/builders/remote-data-build.service.ts
index c0b359e7ea..c98621928c 100644
--- a/src/app/core/cache/builders/remote-data-build.service.ts
+++ b/src/app/core/cache/builders/remote-data-build.service.ts
@@ -1,7 +1,7 @@
 import { Injectable } from '@angular/core';
 
 import { combineLatest as observableCombineLatest, Observable, of as observableOf, race as observableRace } from 'rxjs';
-import { distinctUntilChanged, flatMap, map, startWith, switchMap } from 'rxjs/operators';
+import { distinctUntilChanged, flatMap, map, startWith, switchMap, tap } from 'rxjs/operators';
 
 import { hasValue, hasValueOperator, isEmpty, isNotEmpty, isNotUndefined } from '../../../shared/empty.util';
 import { PaginatedList } from '../../data/paginated-list';
@@ -205,17 +205,29 @@ export class RemoteDataBuildService {
 
     return observableCombineLatest(...input).pipe(
       map((arr) => {
+        // The request of an aggregate RD should be pending if at least one
+        // of the RDs it's based on is still in the state RequestPending
         const requestPending: boolean = arr
           .map((d: RemoteData<T>) => d.isRequestPending)
-          .every((b: boolean) => b === true);
+          .find((b: boolean) => b === true);
 
-        const responsePending: boolean = arr
+        // The response of an aggregate RD should be pending if no requests
+        // are still pending and at least one of the RDs it's based
+        // on is still in the state ResponsePending
+        const responsePending: boolean = !requestPending && arr
           .map((d: RemoteData<T>) => d.isResponsePending)
-          .every((b: boolean) => b === true);
+          .find((b: boolean) => b === true);
 
-        const isSuccessful: boolean = arr
-          .map((d: RemoteData<T>) => d.hasSucceeded)
-          .every((b: boolean) => b === true);
+
+        let isSuccessful: boolean = undefined;
+        // isSuccessful should be undefined until all responses have come in.
+        // We can't know its state beforehand. We also can't say it's false
+        // because that would imply a request failed.
+        if (!(requestPending || responsePending)) {
+          isSuccessful = arr
+            .map((d: RemoteData<T>) => d.hasSucceeded)
+            .every((b: boolean) => b === true);
+        }
 
         const errorMessage: string = arr
           .map((d: RemoteData<T>) => d.error)