Panic when attempting to load issue with invalid label

[CirnoT]

• Gitea version (or commit ref): 1.14.0+dev-605-gd2ea21d0d
• Git version: 2.30.0
• Operating system: Docker
• Database (use [x]):
  • PostgreSQL
  • MySQL
  • MSSQL
  • SQLite
• Can you reproduce the bug at https://try.gitea.io:
  • Yes (provide example URL)
  • No
• Log gist:

2021/01/26 10:41:58 ...els/issue_comment.go:382:LoadLabel() [W] Commit 839 cannot load label 0
2021/01/26 10:41:58 ...els/issue_comment.go:382:LoadLabel() [W] Commit 840 cannot load label 0

Description

template: repo/issue/view_content/comments:188:51: executing "repo/issue/view_content/comments" at <RenderLabels .AddedLabels>: error calling RenderLabels: runtime error: invalid memory address or nil pointer dereference

Additionally; this is a very old issue that might've had some labels before migrating to org-labels; possibly need migration or doctor command to address this issue.

[CirnoT]

delete from comment where type = 7 and label_id = 0;

Seems to have solved the issue. The relevant issues/PRs are from around ~2018.