fix: handle Codeberg returning null entry in requested_reviewers (#136)

Codeberg can return null as part of requested_reviewers (presumably
because that user has been deleted). Handle that case, and also for
assignees since we're at it.

src/service/git/github/github-mapper.ts

@@ -24,8 +24,8 @@ export default class GitHubMapper implements GitResponseMapper<PullRequest, "ope
       state: this.mapGitState(pr.state), // TODO fix using custom mapper
       merged: pr.merged ?? false,
       mergedBy: pr.merged_by?.login,
-      reviewers: pr.requested_reviewers?.filter(r => "login" in r).map((r => (r as User)?.login)) ?? [],
-      assignees: pr.assignees?.filter(r => "login" in r).map(r => r.login) ?? [],
+      reviewers: pr.requested_reviewers?.filter(r => r && "login" in r).map((r => (r as User)?.login)) ?? [],
+      assignees: pr.assignees?.filter(r => r && "login" in r).map(r => r.login) ?? [],
       labels: pr.labels?.map(l => l.name) ?? [],
       sourceRepo: await this.mapSourceRepo(pr),
       targetRepo: await this.mapTargetRepo(pr),

test/support/mock/codeberg-data.ts

@@ -87,7 +87,9 @@ export const CB_MERGED_PR_FIXTURE = {
       "received_events_url": "https://codeberg.org/api/v1/users/gh-user/received_events",
       "type": "User",
       "site_admin": false
-    }
+    },
+    // Sometimes Codeberg returns null as part of requested_reviewers.
+    null,
   ],
   "requested_teams": [