• Gitea version: 1.9.2
• Git version: 1.8.3.1
• Operating system: RHEL 7.6
• Database (use [x]):
  • PostgreSQL
  • MySQL
  • MSSQL
  • SQLite
• Can you reproduce the bug at https://try.gitea.io:
  • Yes (provide example URL)
  • No
  • Not relevant

Description

Steps to reproduce:

• create a new branch
• push branch
• create a new pull request, it will be available to be merged automatically according to Gitea
• clicking the "Merge Pull Request" button results in a 500 error

Log:

2019/08/28 15:30:20 routers/repo/pull.go:629:MergePullRequest() [E] Merge: getDiffTree: git diff-tree [/opt/gitea/data/tmp/local-repo/merge-911475386.git base:master head:head_repo/remove_readme]: fatal: ambiguous argument 'head_repo/remove_readme': unknown revision or path not in the working tree.
	Use '--' to separate paths from revisions, like this:
	'git <command> [<revision>...] -- [<file>...]'

Screenshot