pull: avoid crash of invalid merge head - #2223

pull: avoid crash of invalid merge head#2223

jirikuncar wants to merge 1 commit into

gitgitgadget:mastergitgitgadget/git:masterfrom

jirikuncar:jk/pull-null-merge-headjirikuncar/git:jk/pull-null-merge-headCopy head branch name to clipboard