Allow Git program to be configured via yadm.git-program (#30)

yadm

@@ -30,6 +30,7 @@ YADM_ENCRYPT="encrypt"
 YADM_ARCHIVE="files.gpg"
 
 GPG_PROGRAM="gpg"
+GIT_PROGRAM="git"
 LS_PROGRAM="/bin/ls"
 
 #; flag when something may have changes (which prompts auto actions to be performed)
@@ -112,7 +113,7 @@ function alt() {
   match="^(.+)##($match_system|$match_system.$match_host|$match_system.$match_host.$match_user|())$"
 
   #; process relative to YADM_WORK
-  YADM_WORK=$(git config core.worktree)
+  YADM_WORK=$("$GIT_PROGRAM" config core.worktree)
   cd "$YADM_WORK" || {
     debug "Alternates not processed, unable to cd to $YADM_WORK"
     return
@@ -125,7 +126,7 @@ function alt() {
   #; for every file which matches the above regex, create a symlink
   last_linked=''
   local IFS=$'\n'
-  for tracked_file in $(git ls-files | sort) $(cat "$YADM_ENCRYPT" 2>/dev/null); do
+  for tracked_file in $("$GIT_PROGRAM" ls-files | sort) $(cat "$YADM_ENCRYPT" 2>/dev/null); do
     tracked_file="$YADM_WORK/$tracked_file"
     #; process both the path, and it's parent directory
     for alt_path in "$tracked_file" "${tracked_file%/*}"; do
@@ -154,26 +155,27 @@ function clean() {
 function clone() {
 
   #; clone will begin with a bare repo
-  init
+  local empty=
+  init $empty
 
   #; add the specified remote, and configure the repo to track origin/master
   debug "Adding remote to new repo"
-  git remote add origin "$1"
+  "$GIT_PROGRAM" remote add origin "$@"
   debug "Configuring new repo to track origin/master"
-  git config branch.master.remote origin
-  git config branch.master.merge refs/heads/master
+  "$GIT_PROGRAM" config branch.master.remote origin
+  "$GIT_PROGRAM" config branch.master.merge refs/heads/master
 
   #; fetch / merge (and possibly fallback to reset)
   debug "Doing an initial fetch of the origin"
-  git fetch origin || {
+  "$GIT_PROGRAM" fetch origin || {
     debug "Removing repo after failed clone"
     rm -rf "$YADM_REPO"
     error_out "Unable to fetch origin $1"
   }
   debug "Doing an initial merge of origin/master"
-  git merge origin/master || {
+  "$GIT_PROGRAM" merge origin/master || {
     debug "Merge failed, doing a reset."
-    git reset origin/master
+    "$GIT_PROGRAM" reset origin/master
     cat <<EOF
 **NOTE**
   Merging origin/master failed.
@@ -194,9 +196,6 @@ EOF
 
 function config() {
 
-  #; ensure we have a file, even if empty
-  [ -f "$YADM_CONFIG" ] || touch "$YADM_CONFIG"
-
   if [ -z "$*" ] ; then
     #; with no parameters, provide some helpful documentation
     echo TODO: Print help about available yadm configurations
@@ -212,7 +211,7 @@ function decrypt() {
   require_gpg
   require_archive
 
-  YADM_WORK=$(git config core.worktree)
+  YADM_WORK=$("$GIT_PROGRAM" config core.worktree)
 
   if [ "$DO_LIST" = "YES" ] ; then
     tar_option="t"
@@ -238,7 +237,7 @@ function encrypt() {
   require_ls
 
   #; process relative to YADM_WORK
-  YADM_WORK=$(git config core.worktree)
+  YADM_WORK=$("$GIT_PROGRAM" config core.worktree)
   cd "$YADM_WORK" || {
     debug "Encryption not processed, unable to cd to $YADM_WORK"
     return
@@ -275,14 +274,14 @@ function encrypt() {
   fi
 
   #; offer to add YADM_ARCHIVE if untracked
-  archive_status=$(git status --porcelain -uall "$YADM_ARCHIVE" 2>/dev/null)
+  archive_status=$("$GIT_PROGRAM" status --porcelain -uall "$YADM_ARCHIVE" 2>/dev/null)
   archive_regex="^\?\?"
   if [[ $archive_status =~ $archive_regex ]] ; then
     echo "It appears that $YADM_ARCHIVE is not tracked by yadm's repository."
     echo "Would you like to add it now? (y/n)"
     read -r answer
     if [[ $answer =~ ^[yY]$ ]] ; then
-      git add "$YADM_ARCHIVE"
+      "$GIT_PROGRAM" add "$YADM_ARCHIVE"
     fi
   fi
 
@@ -302,7 +301,7 @@ function git_command() {
   CHANGES_POSSIBLE=1
 
   #; pass commands through to git
-  git "$@"
+  "$GIT_PROGRAM" "$@"
   return "$?"
 }
 
@@ -355,7 +354,7 @@ function init() {
 
   #; init a new bare repo
   debug "Init new repo"
-  git init --shared=0600 --bare "$YADM_REPO"
+  "$GIT_PROGRAM" init --shared=0600 --bare "$YADM_REPO" "$@"
   configure_repo
 
   CHANGES_POSSIBLE=1
@@ -368,7 +367,7 @@ function list() {
 
   #; process relative to YADM_WORK when --all is specified
   if [ -n "$LIST_ALL" ] ; then
-    YADM_WORK=$(git config core.worktree)
+    YADM_WORK=$("$GIT_PROGRAM" config core.worktree)
     cd "$YADM_WORK" || {
       debug "List not processed, unable to cd to $YADM_WORK"
       return
@@ -376,7 +375,7 @@ function list() {
   fi
 
   #; list tracked files
-  git ls-files
+  "$GIT_PROGRAM" ls-files
 
 }
 
@@ -387,7 +386,7 @@ function perms() {
   #; TODO: prevent repeats in the files changed
 
   #; process relative to YADM_WORK
-  YADM_WORK=$(git config core.worktree)
+  YADM_WORK=$("$GIT_PROGRAM" config core.worktree)
   cd "$YADM_WORK" || {
     debug "Perms not processed, unable to cd to $YADM_WORK"
     return
@@ -517,16 +516,16 @@ function configure_repo() {
   debug "Configuring new repo"
 
   #; change bare to false (there is a working directory)
-  git config core.bare 'false'
+  "$GIT_PROGRAM" config core.bare 'false'
 
   #; set the worktree for the yadm repo
-  git config core.worktree "$YADM_WORK"
+  "$GIT_PROGRAM" config core.worktree "$YADM_WORK"
 
   #; by default, do not show untracked files and directories
-  git config status.showUntrackedFiles no
+  "$GIT_PROGRAM" config status.showUntrackedFiles no
 
   #; possibly used later to ensure we're working on the yadm repo
-  git config yadm.managed 'true'
+  "$GIT_PROGRAM" config yadm.managed 'true'
 
 }
 
@@ -578,8 +577,18 @@ function require_encrypt() {
   [ -f "$YADM_ENCRYPT" ] || error_out "$YADM_ENCRYPT does not exist. did you forget to create it?"
 }
 function require_git() {
-  command -v git >/dev/null 2>&1 || \
-    error_out "This functionality requires Git to be installed, but the command git cannot be located."
+  local alt_git
+  alt_git="$(config yadm.git-program)"
+
+  local more_info
+  more_info=""
+
+  if [ "$alt_git" != "" ] ; then
+    GIT_PROGRAM="$alt_git"
+    more_info="\nThis command has been set via the yadm.git-program configuration."
+  fi
+  command -v "$GIT_PROGRAM" >/dev/null 2>&1 || \
+    error_out "This functionality requires Git to be installed, but the command '$GIT_PROGRAM' cannot be located.$more_info"
 }
 function require_gpg() {
   local alt_gpg