Show "Deleted user" if a poll user cannot be found

Fixes an error that would freeze OpenSlides
If a user was deleted but registered as a poll option,
The Assignment Detail View would freeze

client/src/app/site/assignments/modules/assignment-poll/components/assignment-poll-dialog/assignment-poll-dialog.component.html

@@ -14,7 +14,7 @@
             <div *ngFor="let option of options" class="votes-grid">
                 <div>
                     <span *ngIf="option.user">{{ option.user.getFullName() }}</span>
-                    <span *ngIf="!option.user">{{ 'Unknown user' | translate }}</span>
+                    <i *ngIf="!option.user">{{ unknownUserLabel | translate }}</i>
                 </div>
 
                 <div>

client/src/app/site/assignments/modules/assignment-poll/components/assignment-poll-dialog/assignment-poll-dialog.component.ts

@@ -19,7 +19,7 @@ import { BasePollDialogComponent } from 'app/site/polls/components/base-poll-dia
 import { PollFormComponent } from 'app/site/polls/components/poll-form/poll-form.component';
 import { PollPropertyVerbose } from 'app/site/polls/models/view-base-poll';
 import { ViewUser } from 'app/site/users/models/view-user';
-import { AssignmentPollService } from '../../services/assignment-poll.service';
+import { AssignmentPollService, UnknownUserLabel } from '../../services/assignment-poll.service';
 
 type OptionsObject = { user_id: number; user: ViewUser }[];
 
@@ -34,6 +34,7 @@ type OptionsObject = { user_id: number; user: ViewUser }[];
 export class AssignmentPollDialogComponent
     extends BasePollDialogComponent<ViewAssignmentPoll, AssignmentPollService>
     implements OnInit {
+    public unknownUserLabel = UnknownUserLabel;
     /**
      * The summary values that will have fields in the dialog
      */

client/src/app/site/assignments/modules/assignment-poll/components/assignment-poll-vote/assignment-poll-vote.component.html

@@ -51,7 +51,7 @@
                                 {{ option.user.getLevelAndNumber() }}
                             </div>
                         </span>
-                        <span *ngIf="!option.user">{{ 'Unknown user' | translate }}</span>
+                        <i *ngIf="!option.user">{{ unknownUserLabel | translate }}</i>
                     </div>
 
                     <div *ngFor="let action of voteActions">

client/src/app/site/assignments/modules/assignment-poll/components/assignment-poll-vote/assignment-poll-vote.component.scss

@@ -43,7 +43,8 @@
 .vote-candidate-name {
     grid-area: name;
     display: flex;
-    span {
+    span,
+    i {
         margin-top: auto;
         margin-bottom: auto;
     }

client/src/app/site/assignments/modules/assignment-poll/components/assignment-poll-vote/assignment-poll-vote.component.ts

@@ -18,6 +18,7 @@ import { ViewAssignmentOption } from 'app/site/assignments/models/view-assignmen
 import { ViewAssignmentPoll } from 'app/site/assignments/models/view-assignment-poll';
 import { BasePollVoteComponentDirective, VoteOption } from 'app/site/polls/components/base-poll-vote.component';
 import { ViewUser } from 'app/site/users/models/view-user';
+import { UnknownUserLabel } from '../../services/assignment-poll.service';
 
 const voteOptions = {
     Yes: {
@@ -47,6 +48,7 @@ const voteOptions = {
     changeDetection: ChangeDetectionStrategy.OnPush
 })
 export class AssignmentPollVoteComponent extends BasePollVoteComponentDirective<ViewAssignmentPoll> implements OnInit {
+    public unknownUserLabel = UnknownUserLabel;
     public AssignmentPollMethod = AssignmentPollMethod;
     public PollType = PollType;
     public voteActions: VoteOption[] = [];

client/src/app/site/assignments/modules/assignment-poll/components/assignment-poll/assignment-poll.component.ts

@@ -72,15 +72,18 @@ export class AssignmentPollComponent
         this.descriptionForm = this.formBuilder.group({
             description: this.poll ? this.poll.description : ''
         });
-
-        console.log('the poll: ', this.poll);
     }
 
     /**
      * Print the PDF of this poll with the corresponding options and numbers
      */
     public printBallot(): void {
-        this.pdfService.printBallots(this.poll);
+        try {
+            this.pdfService.printBallots(this.poll);
+        } catch (e) {
+            console.error(e);
+            this.raiseError(e);
+        }
     }
 
     public openVotingWarning(): void {

client/src/app/site/assignments/modules/assignment-poll/services/assignment-poll-pdf.service.ts

@@ -141,9 +141,14 @@ export class AssignmentPollPdfService extends PollPdfService {
             return a.weight - b.weight;
         });
         const resultObject = candidates.map(cand => {
-            return poll.pollmethod === AssignmentPollMethod.Y
-                ? this.createBallotOption(cand.user.full_name)
-                : this.createYNBallotEntry(cand.user.full_name, poll.pollmethod);
+            const candidateName = cand.user?.full_name;
+            if (candidateName) {
+                return poll.pollmethod === AssignmentPollMethod.Y
+                    ? this.createBallotOption(candidateName)
+                    : this.createYNBallotEntry(candidateName, poll.pollmethod);
+            } else {
+                throw new Error(this.translate.instant('This ballot contains deleted users.'));
+            }
         });
 
         if (poll.pollmethod === AssignmentPollMethod.Y) {

client/src/app/site/assignments/modules/assignment-poll/services/assignment-poll.service.ts

@@ -1,5 +1,6 @@
 import { Injectable } from '@angular/core';
 
+import { marker as _ } from '@biesbjerg/ngx-translate-extract-marker';
 import { TranslateService } from '@ngx-translate/core';
 
 import { ConstantsService } from 'app/core/core-services/constants.service';
@@ -23,6 +24,7 @@ import {
     VotingResult
 } from 'app/site/polls/services/poll.service';
 
+export const UnknownUserLabel = _('Deleted user');
 @Injectable({
     providedIn: 'root'
 })
@@ -159,11 +161,13 @@ export class AssignmentPollService extends PollService {
                 };
 
                 // Since pollData does not have any subtitle option
-                if (candidate instanceof ViewAssignmentOption) {
+                if (candidate instanceof ViewAssignmentOption && candidate.user) {
                     pollTableEntry.votingOption = candidate.user.short_name;
                     pollTableEntry.votingOptionSubtitle = candidate.user.getLevelAndNumber();
-                } else {
+                } else if (candidate.user) {
                     pollTableEntry.votingOption = (candidate as PollDataOption).user.short_name;
+                } else {
+                    pollTableEntry.votingOption = UnknownUserLabel;
                 }
 
                 return pollTableEntry;
@@ -248,8 +252,8 @@ export class AssignmentPollService extends PollService {
                 }
                 return resultLabel;
             });
-
-            return `${option.user.short_name} · ${votingResults.join(' · ')}`;
+            const optionName = option.user?.short_name ?? UnknownUserLabel;
+            return `${optionName} · ${votingResults.join(' · ')}`;
         });
     }
 }

client/src/app/slides/assignments/assignment/assignment-slide.component.html

@@ -10,12 +10,12 @@
     <ng-container *ngIf="data.data.assignment_related_users && data.data.assignment_related_users.length">
         <ol *ngIf="data.data.number_poll_candidates">
             <li *ngFor="let candidate of data.data.assignment_related_users">
-                {{ candidate.user }}
+                {{ getUserName(candidate) }}
             </li>
         </ol>
         <ul *ngIf="!data.data.number_poll_candidates">
             <li *ngFor="let candidate of data.data.assignment_related_users">
-                {{ candidate.user }}
+                {{ getUserName(candidate) }}
             </li>
         </ul>
     </ng-container>

client/src/app/slides/assignments/assignment/assignment-slide.component.ts

@@ -26,4 +26,8 @@ export class AssignmentSlideComponent extends BaseSlideComponentDirective<Assign
     public constructor() {
         super();
     }
+
+    public getUserName(relatedUser: { user: string }): string {
+        return relatedUser.user;
+    }
 }