[PATCH] vcs_info: git: Support stagedstr(%c) without unstagedstr(%u)

[Daniel Shahaf <d.s@xxxxxxxxxxxxxxxxxx>]

Hello.

I'd like to have my prompt alert me when I have staged changes (because it's a
pain to keep running 'git diff --staged' before every 'git commit -a').
However, I don't want to enable detection of unstaged changes too as that's
more expensive (disk crawl v. metadata crawl).

Put another way, I want to have %c/stagedstr without the cost of %u/unstagestr.

The current code makes detection of %u,%c an all-or-nothing deal:

    # excerpt from Functions/VCS_Info/Backends/VCS_INFO_get_data_git
    if zstyle -t ":vcs_info:${vcs}:${usercontext}:${rrn}" "check-for-changes" && ... ; then
        # Default: off - these are potentially expensive on big repositories
        ${vcs_comm[cmd]} diff --no-ext-diff --ignore-submodules --quiet --exit-code ||
            gitunstaged=1
        ${vcs_comm[cmd]} diff-index --cached --quiet --ignore-submodules HEAD 2> /dev/null
        (( $? && $? != 128 )) && gitstaged=1
    fi

I went ahead and implemented a way to enable %c without %u, specifically by
adding a 'check-for-staged-changes' style that sets %c but not %u and leaving
'check-for-changes' unchanged (sets both %c and %u).  See attached patch.

WDYT?

Daniel

---

Recipe for testing:

zsh -f
cd $MY_ZSH_SOURCE_DIR
zstyle ':vcs_info:git:*' stagedstr '[+]'
zstyle ':vcs_info:git:*' check-for-staged-changes true
zstyle ':vcs_info:git:*' formats '%b%c'
fpath=( $PWD/Functions/**/*(/) )
autoload -Uz vcs_info
_precmd_vcs_info() { vcs_info; print -P ${vcs_info_msg_0_} }
precmd_functions+=(_precmd_vcs_info)
git rm --quiet -- README
git checkout HEAD -- README
# Observe the last two prompts.

From 8274b8113f0b4c17f9fd2532dc58db7b82042c1d Mon Sep 17 00:00:00 2001
From: Daniel Shahaf <d.s@xxxxxxxxxxxxxxxxxx>
Date: Fri, 28 Mar 2014 11:00:35 +0000
Subject: [PATCH 3/3] vcs_info: Add check-for-staged-changes

---
 Completion/Zsh/Command/_zstyle                    |    2 ++
 Doc/Zsh/contrib.yo                                |   13 +++++++++++++
 Functions/VCS_Info/Backends/VCS_INFO_get_data_bzr |    2 ++
 Functions/VCS_Info/Backends/VCS_INFO_get_data_git |   21 ++++++++++++++++-----
 Misc/vcs_info-examples                            |    4 ++++
 5 files changed, 37 insertions(+), 5 deletions(-)

diff --git a/Completion/Zsh/Command/_zstyle b/Completion/Zsh/Command/_zstyle
index 708c0fd..eb27117 100644
--- a/Completion/Zsh/Command/_zstyle
+++ b/Completion/Zsh/Command/_zstyle
@@ -182,6 +182,8 @@ styles=(
   disable                v:vcs
   disable-patterns       v:
   check-for-changes      v:bool
+  check-for-staged-changes
+                         v:bool
   stagedstr              v:
   unstagedstr            v:
   command                v:_command_names
diff --git a/Doc/Zsh/contrib.yo b/Doc/Zsh/contrib.yo
index 76f456a..01d5b6a 100644
--- a/Doc/Zsh/contrib.yo
+++ b/Doc/Zsh/contrib.yo
@@ -837,6 +837,18 @@ Note, the actions taken if this style is enabled are potentially expensive
 (read: they may be slow, depending on how big the current repository is).
 Therefore, it is disabled by default.
 )
+kindex(check-for-staged-changes)
+item(tt(check-for-staged-changes))(
+This style is like tt(check-for-changes), but it never checks the worktree
+files, only the metadata in the tt(.${vcs}) dir.  Therefore,
+this style initializes only the tt(%c) escape (with tt(stagedstr)) but
+not the tt(%u) escape.  This style is faster than tt(check-for-changes).
+
+In the tt(git) backend, this style checks for changes in the index.
+Other backends do not currently implement this style.
+
+This style is disabled by default.
+)
 kindex(stagedstr)
 item(tt(stagedstr))(
 This string will be used in the tt(%c) escape if there are staged changes in
@@ -941,6 +953,7 @@ sitem(tt(enable))(ALL)
 sitem(tt(disable))((empty list))
 sitem(tt(disable-patterns))((empty list))
 sitem(tt(check-for-changes))(false)
+sitem(tt(check-for-staged-changes))(false)
 sitem(tt(stagedstr))((string: "S"))
 sitem(tt(unstagedstr))((string: "U"))
 sitem(tt(command))((empty string))
diff --git a/Functions/VCS_Info/Backends/VCS_INFO_get_data_bzr b/Functions/VCS_Info/Backends/VCS_INFO_get_data_bzr
index 6e96ece..3198915 100644
--- a/Functions/VCS_Info/Backends/VCS_INFO_get_data_bzr
+++ b/Functions/VCS_Info/Backends/VCS_INFO_get_data_bzr
@@ -11,6 +11,8 @@ local -xA hook_com bzr_info
 VCS_INFO_bzr_get_info() {
     bzrinfo=( ${(s.:.)$( ${vcs_comm[cmd]} version-info --custom \
         --template="{revno}:{branch_nick}:{clean}")} )
+    # TODO: document in zshcontrib that bzr supports check-for-changes
+    # (also in VCS_INFO_bzr_get_info_restricted)
     if zstyle -t ":vcs_info:${vcs}:${usercontext}:${rrn}" "check-for-changes"
     then
         VCS_INFO_bzr_get_changes
diff --git a/Functions/VCS_Info/Backends/VCS_INFO_get_data_git b/Functions/VCS_Info/Backends/VCS_INFO_get_data_git
index e6791cb..abe388b 100644
--- a/Functions/VCS_Info/Backends/VCS_INFO_get_data_git
+++ b/Functions/VCS_Info/Backends/VCS_INFO_get_data_git
@@ -5,6 +5,7 @@
 setopt localoptions extendedglob NO_shwordsplit
 local gitdir gitbase gitbranch gitaction gitunstaged gitstaged gitsha1
 local stgitpatch stgitunapplied
+local querystaged queryunstaged
 local -A hook_com
 
 VCS_INFO_git_getaction () {
@@ -120,14 +121,24 @@ if [[ -z ${gitdir} ]] || [[ -z ${gitbranch} ]] ; then
     return 1
 fi
 
-if zstyle -t ":vcs_info:${vcs}:${usercontext}:${rrn}" "check-for-changes" && \
+if zstyle -t ":vcs_info:${vcs}:${usercontext}:${rrn}" "check-for-changes" ; then
+    querystaged=1
+    queryunstaged=1
+elif zstyle -t ":vcs_info:${vcs}:${usercontext}:${rrn}" "check-for-staged-changes" ; then
+    querystaged=1
+fi
+if [[ -n $querystaged || -n $queryunstaged ]] && \
    [[ "$(${vcs_comm[cmd]} rev-parse --is-inside-git-dir 2> /dev/null)" != 'true' ]] && \
    ${vcs_comm[cmd]} rev-parse --quiet --verify HEAD &> /dev/null ; then
     # Default: off - these are potentially expensive on big repositories
-    ${vcs_comm[cmd]} diff --no-ext-diff --ignore-submodules --quiet --exit-code ||
-        gitunstaged=1
-    ${vcs_comm[cmd]} diff-index --cached --quiet --ignore-submodules HEAD 2> /dev/null
-    (( $? && $? != 128 )) && gitstaged=1
+    if [[ -n $queryunstaged ]] ; then
+        ${vcs_comm[cmd]} diff --no-ext-diff --ignore-submodules --quiet --exit-code ||
+            gitunstaged=1
+    fi
+    if [[ -n $querystaged ]] ; then
+        ${vcs_comm[cmd]} diff-index --cached --quiet --ignore-submodules HEAD 2> /dev/null
+        (( $? && $? != 128 )) && gitstaged=1
+    fi
 fi
 
 VCS_INFO_adjust
diff --git a/Misc/vcs_info-examples b/Misc/vcs_info-examples
index b07bfc6..5d8ff18 100644
--- a/Misc/vcs_info-examples
+++ b/Misc/vcs_info-examples
@@ -266,6 +266,10 @@ autoload -Uz vcs_info
 zstyle ':vcs_info:*' check-for-changes true
 zstyle ':vcs_info:*' get-revision true
 
+# Alternatively, the following would set only %c, but is faster:
+#zstyle ':vcs_info:*' check-for-changes false
+#zstyle ':vcs_info:*' check-for-staged-changes true
+
 
 # Default to running vcs_info. If possible we prevent running it later for
 # speed reasons. If set to a non empty value vcs_info is run.
-- 
1.7.10.4