Fix: file commands do not work with paths containing special characters

Git escapes special characters in it's output when core.quotePath is
true or unset. Git always expects unquoted file paths as input. This
leads to issues when we consume output from git and use it to build
input for other git commands. This commit ensures we always feed unqoted
paths to git commands.
The _forgit_list_files function is introduced to handle usage of git
ls-files with the -z flag, which ensures unquoted paths.
It replaces the direct calls to git ls-files in _forgit_reset_head,
_forgit_stash_push and _forgit_checkout_file.
In _forgit_add the current approach of using colors to separate unstaged
from staged files is replaced with a call to _forgit_ls_files with the
appropriate flags to only list unstaged files.
In _git_reset_head the -z option is added to the git diff command to
ensure unqoted paths.
Since git clean does not support the -z flag, we disable core.quotePath
by passing a configuration parameter in _forgit_clean.

bin/git-forgit

@@ -159,6 +159,21 @@ _forgit_is_file_tracked() {
     git ls-files "$1" --error-unmatch &> /dev/null
 }
 
+_forgit_list_files() {
+    local rootdir
+    rootdir=$(git rev-parse --show-toplevel)
+    # git escapes special characters in it's output when core.quotePath is
+    # true or unset. Git always expects unquoted file paths as input. This
+    # leads to issues when we consume output from git and use it to build
+    # input for other git commands. Use the -z flag to ensure file paths are
+    # unquoted.
+    # uniq is necessary because unmerged files are printed once for each
+    # merge conflict.
+    # With the -z flag, git also uses \0 line termination, so we 
+    # have to replace the terminators.
+    git ls-files -z "$@" "$rootdir" | uniq | tr '\0' '\n'
+}
+
 _forgit_log_preview() {
     local sha
     sha=$(echo "$1" | _forgit_extract_sha)
@@ -329,13 +344,10 @@ _forgit_edit_add_file() {
 # git add selector
 _forgit_add() {
     _forgit_inside_work_tree || return 1
-    local changed unmerged untracked files opts
+    local files opts
     # Add files if passed as arguments
     [[ $# -ne 0 ]] && { _forgit_git_add "$@" && git status -su; return $?; }
 
-    changed=$(git config --get-color color.status.changed red)
-    unmerged=$(git config --get-color color.status.unmerged red)
-    untracked=$(git config --get-color color.status.untracked red)
     opts="
         $FORGIT_FZF_DEFAULT_OPTS
         -0 -m --nth 2..,..
@@ -346,8 +358,7 @@ _forgit_add() {
     files=()
     while IFS='' read -r file; do
         files+=("$file")
-    done < <(git -c color.status=always -c status.relativePaths=true status -su |
-        grep -F -e "$changed" -e "$unmerged" -e "$untracked" |
+    done < <(_forgit_list_files --exclude-standard --modified --others |
         sed -E 's/^(..[^[:space:]]*)[[:space:]]+(.*)$/[\1]  \2/' |
         FZF_DEFAULT_OPTS="$opts" fzf |
         _forgit_get_single_file_from_add_line)
@@ -381,7 +392,7 @@ _forgit_reset_head() {
     files=()
     while IFS='' read -r file; do
         files+=("$file")
-    done < <(git diff --staged --name-only | FZF_DEFAULT_OPTS="$opts" fzf)
+    done < <(git diff -z --staged --name-only | tr '\0' '\n' | FZF_DEFAULT_OPTS="$opts" fzf)
     if [[ ${#files} -eq 0 ]]; then
         echo 'Nothing to unstage.'
         return 1
@@ -455,19 +466,18 @@ _forgit_stash_push() {
             *) _forgit_git_stash_push "${args[@]}"; return $?
         esac
     done
-    local opts files rootdir
+    local opts files
     opts="
         $FORGIT_FZF_DEFAULT_OPTS
         -m
         --preview=\"$FORGIT stash_push_preview {}\"
         $FORGIT_STASH_PUSH_FZF_OPTS
     "
-    rootdir=$(git rev-parse --show-toplevel)
     # Show both modified and untracked files
     files=()
     while IFS='' read -r file; do
         files+=("$file")
-    done < <(git ls-files "$rootdir" --exclude-standard --modified --others |
+    done < <(_forgit_list_files --exclude-standard --modified --others |
         FZF_DEFAULT_OPTS="$opts" fzf --exit-0)
     [[ "${#files[@]}" -eq 0 ]] && echo "Nothing to stash" && return 1
     _forgit_git_stash_push ${msg:+-m "$msg"} -u "${files[@]}"
@@ -497,7 +507,7 @@ _forgit_clean() {
         $FORGIT_CLEAN_FZF_OPTS
     "
     # Note: Postfix '/' in directory path should be removed. Otherwise the directory itself will not be removed.
-    files=$(git clean -xdffn "$@"| sed 's/^Would remove //' | FZF_DEFAULT_OPTS="$opts" fzf |sed 's#/$##')
+    files=$(git -c core.quotePath=false clean -xdffn "$@"| sed 's/^Would remove //' | FZF_DEFAULT_OPTS="$opts" fzf |sed 's#/$##')
     [[ -n "$files" ]] && echo "$files" | tr '\n' '\0' | xargs -0 -I% git clean "${_forgit_clean_git_opts[@]}" -xdff '%' && git status --short && return
     echo 'Nothing to clean.'
 }
@@ -675,7 +685,7 @@ _forgit_checkout_file() {
     files=()
     while IFS='' read -r file; do
         files+=("$file")
-    done < <(git ls-files --modified "$(git rev-parse --show-toplevel)" |
+    done < <(_forgit_list_files --modified |
         FZF_DEFAULT_OPTS="$opts" fzf)
     [[ "${#files[@]}" -gt 0 ]] && _forgit_git_checkout_file "${files[@]}"
 }