Git plugin: Replace calls to git status with porcelain commands

plugins/git/functions/git-info

@@ -172,6 +172,8 @@ function git-info() {
   local git_info_var
   local -A git_info_vars
   local status_cmd
+  local remote_cmd
+  local upstream_diff_cmd
   local ignore_submodule
   local ignore_submodule_when
 
@@ -204,7 +206,11 @@ function git-info() {
   _git_info_executing=true
 
   # Use short status for easy parsing.
-  status_cmd='git status --short --branch'
+  status_cmd='git status --porcelain'
+  # Get remote's name.
+  remote_cmd='git rev-parse --verify HEAD@{upstream} --symbolic-full-name'
+  # Get commits count between the local and the remote branch
+  upstream_diff_cmd='git rev-list --count --left-right @{upstream}...HEAD'
 
   # Ignore submodule status.
   zstyle -b \
@@ -231,88 +237,56 @@ function git-info() {
     zformat -f stashed_formatted "$stashed_format" "S:$stashed"
   fi
 
-  while IFS=$'\n' read line; do
-    (( line_number++ ))
-
-    if (( line_number == 1 )) && [[ "$line" == *'(no branch)'* ]]; then
-      # Get action.
-      action="$(_git-action)"
+  # Format action.
+  action="$(_git-action)"
+  if [[ -n "$action" ]]; then
+    zstyle -s ':omz:plugin:git:prompt' action 'action_format'
+    zformat -f action_formatted "$action_format" "s:$action"
+  fi
 
-      # Format action.
-      if [[ -n "$action" ]]; then
-        zstyle -s ':omz:plugin:git:prompt' action 'action_format'
-        zformat -f action_formatted "$action_format" "s:$action"
-      fi
-    elif (( line_number == 1 )) \
-      && [[ "$line" == (#b)'## Initial commit on '(?##) ]];
-    then
-      branch="$match[1]"
-    elif (( line_number == 1 )); then
-      # Split the line into an array for parsing.
-      branch_info=(${(s: :)line})
-
-      # Match: master...origin/master
-      if [[ "$branch_info[2]" == (#b)(?##)...(?##/?##) ]]; then
-        branch="$match[1]"
-        remote="$match[2]"
-
-        # Match: [ahead or [behind
-        if [[ "$branch_info[3]" == (#b)\[(ahead|behind) ]]; then
-          ahead_or_behind="$match[1]"
-          if [[ "$ahead_or_behind" == 'behind' ]]; then
-            # Extract digits: 10]
-            behind="${branch_info[4]%\]}"
-          else
-            # Extract digits: 10] or 10,
-            ahead="${branch_info[4]%[,\]]}"
-            # Extract digits: 10]
-            behind="${branch_info[6]%\]}"
-          fi
-        fi
-      # Match: master
-      elif [[ "$branch_info[2]" == (#b)(?##) ]]; then
-        branch="$match[1]"
-      fi
-    else
-      # Count added, deleted, modified, renamed, unmerged, untracked, dirty.
-      # T (type change) is undocumented, see http://git.io/FnpMGw.
-      # For a table of scenarii, see http://i.imgur.com/2YLu1.png.
-      [[ "$line" == ([ACDMT][\ MT]|[ACMT]D)\ * ]] && (( added++ ))
-      [[ "$line" == [\ ACMRT]D\ * ]] && (( deleted++ ))
-      [[ "$line" == ?[MT]\ * ]] && (( modified++ ))
-      [[ "$line" == R?\ * ]] && (( renamed++ ))
-      [[ "$line" == (AA|DD|U?|?U)\ * ]] && (( unmerged++ ))
-      [[ "$line" == \?\?\ * ]] && (( untracked++ ))
-      (( dirty++ ))
-    fi
-  done < <("${(z)status_cmd}" 2>/dev/null)
+  # Get current status.
+  while IFS=$'\n' read line; do
+    # Count added, deleted, modified, renamed, unmerged, untracked, dirty.
+    # T (type change) is undocumented, see http://git.io/FnpMGw.
+    # For a table of scenarii, see http://i.imgur.com/2YLu1.png.
+    [[ "$line" == ([ACDMT][\ MT]|[ACMT]D)\ * ]] && (( added++ ))
+    [[ "$line" == [\ ACMRT]D\ * ]] && (( deleted++ ))
+    [[ "$line" == ?[MT]\ * ]] && (( modified++ ))
+    [[ "$line" == R?\ * ]] && (( renamed++ ))
+    [[ "$line" == (AA|DD|U?|?U)\ * ]] && (( unmerged++ ))
+    [[ "$line" == \?\?\ * ]] && (( untracked++ ))
+    (( dirty++ ))
+  done < <(${(z)status_cmd} 2>/dev/null)
 
   # Format branch.
+  branch=${$(git symbolic-ref -q HEAD)##refs/heads/}
   if [[ -n "$branch" ]]; then
     zstyle -s ':omz:plugin:git:prompt' branch 'branch_format'
     zformat -f branch_formatted "$branch_format" "b:$branch"
 
     # Format remote.
-    if [[ -z "$remote" ]]; then
-      remote="${$( \
-        git rev-parse \
-          --verify ${branch}@{upstream} \
-          --symbolic-full-name 2>/dev/null)#refs/remotes/}"
-    fi
-    zstyle -s ':omz:plugin:git:prompt' remote 'remote_format'
-    zformat -f remote_formatted "$remote_format" "R:$remote"
-  fi
-
-  # Format ahead.
-  if [[ -n "$ahead" ]]; then
-    zstyle -s ':omz:plugin:git:prompt' ahead 'ahead_format'
-    zformat -f ahead_formatted "$ahead_format" "A:$ahead"
-  fi
+    remote=${$(${(z)remote_cmd} 2>/dev/null)##refs/remotes/}
+    if [[ -n "$remote" ]]; then
+      zstyle -s ':omz:plugin:git:prompt' remote 'remote_format'
+      zformat -f remote_formatted "$remote_format" "R:$remote"
+
+      # Get difference with remote.
+      upstream_diff=$(${(z)upstream_diff_cmd} 2>/dev/null)
+
+      # Format ahead.
+      ahead=$upstream_diff[(w)2]
+      if [[ $ahead > 0 ]]; then
+        zstyle -s ':omz:plugin:git:prompt' ahead 'ahead_format'
+        zformat -f ahead_formatted "$ahead_format" "A:$ahead"
+      fi
 
-  # Format behind.
-  if [[ -n "$behind" ]]; then
-    zstyle -s ':omz:plugin:git:prompt' behind 'behind_format'
-    zformat -f behind_formatted "$behind_format" "B:$behind"
+      # Format behind.
+      behind=$upstream_diff[(w)1]
+      if [[ $behind > 0 ]]; then
+        zstyle -s ':omz:plugin:git:prompt' behind 'behind_format'
+        zformat -f behind_formatted "$behind_format" "B:$behind"
+      fi
+    fi
   fi
 
   # Format added.