fix(ownership): Handle ownership rule owners without an id

static/app/types/group.tsx

@@ -523,9 +523,18 @@ type SuggestedOwner = {
   type: SuggestedOwnerReason;
 };
 
+/**
+ * Mirrors OwnershipRuleOwnerResponse from the backend
+ */
+interface OwnershipRuleOwner {
+  name: string;
+  type: 'user' | 'team';
+  id?: string;
+}
+
 export interface ParsedOwnershipRule {
   matcher: {pattern: string; type: string};
-  owners: Actor[];
+  owners: OwnershipRuleOwner[];
 }
 
 export type IssueOwnership = {

static/app/views/settings/project/projectOwnership/ownershipRulesTable.spec.tsx

@@ -168,6 +168,32 @@ describe('OwnershipRulesTable', () => {
     expect(screen.getByRole('button', {name: 'Everyone'})).toBeInTheDocument();
   });
 
+  it('should render owners without an id', async () => {
+    const rules: ParsedOwnershipRule[] = [
+      {
+        matcher: {pattern: 'src/app/*', type: 'path'},
+        owners: [{type: 'user', name: 'unresolved-user@example.com'}],
+      },
+      {
+        matcher: {pattern: 'src/utils/*', type: 'path'},
+        owners: [
+          {type: 'user', id: user1.id, name: user1.name},
+          {type: 'team', name: 'backend'},
+        ],
+      },
+    ];
+
+    render(<OwnershipRulesTable projectRules={rules} codeowners={[]} />);
+
+    // Clear the "My Teams" filter to see all rules
+    await userEvent.click(screen.getByRole('button', {name: 'My Teams'}));
+    await userEvent.click(screen.getByRole('button', {name: 'Clear'}));
+
+    expect(screen.getByText('src/app/*')).toBeInTheDocument();
+    expect(screen.getByText('unresolved-user@example.com')).toBeInTheDocument();
+    expect(screen.getByText('src/utils/*')).toBeInTheDocument();
+  });
+
   it('should paginate results', async () => {
     const owners: Actor[] = [{type: 'user', id: user1.id, name: user1.name}];
     const rules: ParsedOwnershipRule[] = new Array(100).fill(0).map((_, i) => ({

static/app/views/settings/project/projectOwnership/ownershipRulesTable.tsx

@@ -16,8 +16,10 @@ import {IconChevron} from 'sentry/icons';
 import {t, tn} from 'sentry/locale';
 import {MemberListStore} from 'sentry/stores/memberListStore';
 import {TeamStore} from 'sentry/stores/teamStore';
+import type {Actor} from 'sentry/types/core';
 import type {ParsedOwnershipRule} from 'sentry/types/group';
 import type {CodeOwner} from 'sentry/types/integrations';
+import {defined} from 'sentry/utils';
 import {useTeams} from 'sentry/utils/useTeams';
 import {useUser} from 'sentry/utils/useUser';
 import {OwnershipOwnerFilter} from 'sentry/views/settings/project/projectOwnership/ownershipOwnerFilter';
@@ -84,6 +86,10 @@ export function OwnershipRulesTable({
   const myTeams = useMemo(() => {
     const memberTeamsIds = teams.filter(team => team.isMember).map(team => team.id);
     return allActors.filter(actor => {
+      if (!defined(actor.id)) {
+        return false;
+      }
+
       if (actor.type === 'user') {
         return actor.id === user.id;
       }
@@ -140,7 +146,7 @@ export function OwnershipRulesTable({
     <RulesTableWrapper data-test-id="ownership-rules-table">
       <Flex align="center" gap="xl">
         <OwnershipOwnerFilter
-          actors={allActors}
+          actors={allActors.filter((actor): actor is Actor => defined(actor.id))}
           selectedTeams={selectedActors ?? []}
           handleChangeFilter={handleChangeFilter}
           isMyTeams={
@@ -166,7 +172,11 @@ export function OwnershipRulesTable({
         emptyMessage={t('No ownership rules found')}
       >
         {chunkedRules[page]?.map((rule, index) => {
+          const hasUnknownOwners = rule.owners.some(owner => !defined(owner.id));
           const ownerNames = rule.owners.map(owner => {
+            if (!owner.id) {
+              return owner.name;
+            }
             if (owner.type === 'team') {
               const team = TeamStore.getById(owner.id);
               return team?.slug ? `#${team.slug}` : owner.name;
@@ -185,12 +195,15 @@ export function OwnershipRulesTable({
               <RowRule>{rule.matcher.pattern}</RowRule>
               <Flex align="center" gap="md">
                 <AvatarContainer numAvatars={Math.min(rule.owners.length, 3)}>
-                  <SuggestedAvatarStack
-                    owners={rule.owners}
-                    suggested={false}
-                    reverse={false}
-                    tooltip={ownerNames.join(', ')}
-                  />
+                  {/* Avoid attempting to render the avatar stack if there are broken owners */}
+                  {!hasUnknownOwners && (
+                    <SuggestedAvatarStack
+                      owners={rule.owners as Actor[]}
+                      suggested={false}
+                      reverse={false}
+                      tooltip={ownerNames.join(', ')}
+                    />
+                  )}
                 </AvatarContainer>
                 {name}
                 {rule.owners.length > 1 &&