Git completion with zsh: filenames with spaces aren’t being escaped properly

I assume you're using the “new” completion system enabled by compinit. If you're using oh-my-zsh, you are.

You need to tell zsh to use git branch names for gpDo. Git already comes with a way to complete branch names. As of zsh 5.0.7 this is the function __git_branch_names but this isn't a stable interface so it could change in other versions. To use this function, put this line in your .zshrc:

compdef __git_branch_names gpDo

With this declaration, completion after gpDo will only work after you've completed something on a git command line at least once. This is due to a quirk of function autoloading in zsh. Alternatively, run _git 2>/dev/null in your .zshrc; this causes an error because the completion function is called in an invalid context, but the error is harmless, and the side effect of loading _git and associated functions including __git_branch_names` remains.

Alternatively, define your own function for git branch completion. Quick-and-dirty way:

_JJD_git_branch_names () {
  compadd "${(@)${(f)$(git branch -a)}#??}"
}

Sadly, its a bug in zsh completion for git. You can find discussion on 'zsh' mailing list here.

Daniel Shahaf did provided a patch for '_git':

diff --git a/Completion/Unix/Command/_git b/Completion/Unix/Command/_git
index 518e6d198..45a0fa622 100644
--- a/Completion/Unix/Command/_git
+++ b/Completion/Unix/Command/_git
@@ -6609,20 +6609,33 @@ __git_files_relative () {
 (( $+functions[__git_files] )) ||
 __git_files () {
   local compadd_opts opts tag description gitcdup gitprefix files expl
+  local pref

   zparseopts -D -E -a compadd_opts V: J: 1 2 n f X: M: P: S: r: R: q F:
   zparseopts -D -E -a opts -- -cached -deleted -modified -others -ignored -unmerged -killed x+: --exclude+:
   tag=$1 description=$2; shift 2

-  gitcdup=$(_call_program gitcdup git rev-parse --show-cdup 2>/dev/null)
-  __git_command_successful $pipestatus || return 1
+  case $(_call_program gitinworktree git rev-parse --is-inside-work-tree 2>/dev/null) in
+    (true)
+      gitcdup=$(_call_program gitcdup git rev-parse --show-cdup 2>/dev/null)
+      __git_command_successful $pipestatus || return 1

-  gitprefix=$(_call_program gitprefix git rev-parse --show-prefix 2>/dev/null)
-  __git_command_successful $pipestatus || return 1
+      gitprefix=$(_call_program gitprefix git rev-parse --show-prefix 2>/dev/null)
+      __git_command_successful $pipestatus || return 1
+
+      local pref=$gitcdup$gitprefix$PREFIX
+      ;;
+    (false)
+      local pref=
+      ;;
+    (*)
+      # XXX what to do?
+      return 1
+      ;;
+  esac

   # TODO: --directory should probably be added to $opts when --others is given.

-  local pref=$gitcdup$gitprefix$PREFIX

   # First allow ls-files to pattern-match in case of remote repository
   files=(${(0)"$(_call_program files git ls-files -z --exclude-standard ${(q)opts} -- ${(q)${pref:+$pref\\\*}} 2>/dev/null)"})
@@ -7585,7 +7598,8 @@ _git() {
         ;;
       (option-or-argument)
         curcontext=${curcontext%:*:*}:git-$words[1]:
-       (( $+opt_args[--git-dir] )) && local -x GIT_DIR=$opt_args[--git-dir]
+        (( $+opt_args[--git-dir] )) && local -x GIT_DIR=${(e)opt_args[--git-dir]}
+        (( $+opt_args[--work-tree] )) && local -x GIT_WORK_TREE=${(e)opt_args[--work-tree]}
        if ! _call_function ret _git-$words[1]; then
          if zstyle -T :completion:$curcontext: use-fallback; then
            _default && ret=0

It applies clearly to zsh 5.4.1 but it didn't work form me,YMMV.

I'll update this answer as the issue is being worked on.

EDIT:

With the above patch it does work, but where you put add is important - it has to be at the end:

git --git-dir=$HOME/.dotfiles --work-tree=$HOME/ add

One more thing worth noticing - its somewhat slow.