(defun vc-git-conflicted-files (directory)
"Return the list of files with conflicts in DIRECTORY."
(let* ((status
(vc-git--run-command-string directory "status" "--porcelain" "--"))
I'm working around this issue by changing vc-git-conflicted-files to use diff-files --name-status, which doesn't lock the index:
(defun vc-git-conflicted-files (directory)
"Return the list of files with conflicts in DIRECTORY."
(let* ((status
(vc-git--run-command-string directory "diff-files" "--name-status"))
(lines (when status (split-string status "\n" 'omit-nulls)))
files)
;; TODO: Look into reimplementing `vc-git-state', as well as
;; `vc-git-dir-status-files', based on this output, thus making the
;; extra process call in `vc-git-find-file-hook' unnecessary.
(dolist (line lines files)
(when (string-match "\\([ MADRCU?!]\\)[ \t]+\\(.+\\)" line)
(let ((state (match-string 1 line))
(file (match-string 2 line)))
;; See git-status(1).
(when (equal state "U")
(push (expand-file-name file directory) files)))))))