git-pull-ff

#!/bin/bash

### This Git method script pulls all new commits, branches and tags from all
### known remote sources, and attempts fast-forward merges of the current
### workspace with its more up-to-date remote counterparts.
### Script Copyright (C) 2014-2015 by Jim Klimov, License: MIT
### Pieces probably inspired by various posts from Stack Overflow

PATH=/usr/gnu/bin:/usr/sfw/bin:/opt/sfw/bin:/opt/omniti/bin:/bin:/usr/bin:\
/sbin:/usr/sbin:$PATH
LANG=C
LC_ALL=C
export PATH LANG LC_ALL

git_pull_ff() {

currentbranchref="$(git symbolic-ref HEAD 2>&-)"
currentbranch="`git branch | grep '^* ' | sed 's,^* ,,'`" || \
	currentbranch=""

TS="`date -u '+%Y%m%dT%H%M%SZ'`" || \
    TS="`date | sed 's,[\@\:\ ],_,g'`" || \
    TS="before-git-pull-ff$$"
repodir="$(git rev-parse --show-toplevel)" && \
    [ -d "$repodir/.zfs/snapshot" ] && \
    echo "Trying to make ZFS snapshots '@$TS' of the repo dataset during git-pulling..." && \
    mkdir "$repodir/.zfs/snapshot/git-pull-ff--$TS--0--beforePulls" || true


#git pull $currentbranch
#git pull --tags $currentbranch

### Remove local branches deleted remotely
### TODO : not by default, add an option/envvar to enable this
#git fetch --all --prune

git pull --all
git pull --all --recurse-submodules=yes
git fetch --tags
git fetch --tags --recurse-submodules=yes

BREAK=no
trapbreak() {
    if [ "$BREAK" = yes ] ; then
        echo "Stopping due to multiple breaks..."
        if [ x"$currentbranch" != x -a "$currentbranch" != master ]; then
            echo "Trying to return to branch $currentbranch..."
            git checkout $currentbranch
            git branch
        fi

        [ -d "$repodir/.zfs/snapshot" ] && \
        mkdir "$repodir/.zfs/snapshot/git-pull-ff--$TS--X--CleanupAfterGotBreak" || true

        exit 1
    fi >&2

    echo 'Got stop signal, please wait until the end of critical section' >&2
    BREAK=yes
}

checkbreak() {
    [ "$BREAK" = yes ] && echo "Stopping due to break" && exit 1
    return 0
}

git branch -r | grep -v ' -> ' | while read remotebranch
do
    # Split <remote>/<branch> into remote and branchref parts
    remote="${remotebranch%%/*}"
    branchref="refs/heads/${remotebranch#*/}"

    if [ "$branchref" == "$currentbranchref" ]
    then
        echo "Updating current branch $branchref from $remote..."
        git pull --ff-only
    else
        echo "Updating non-current ref $branchref from $remote..."
        git fetch "$remote" "$branchref:$branchref"
    fi
done

[ -d "$repodir/.zfs/snapshot" ] && \
    mkdir "$repodir/.zfs/snapshot/git-pull-ff--$TS--1--afterRemoteFetched" || true

echo  "NOTE: Setting trap to avoid bad breakage (current-branch mismatch) on Ctrl+C"
trap "trapbreak" 1 2 3 15

git checkout master && \
git pull --ff-only --all
git pull --ff-only --all --recurse-submodules=yes
#git pull --ff-only master && \
#git pull --ff-only --all

[ -d "$repodir/.zfs/snapshot" ] && \
    mkdir "$repodir/.zfs/snapshot/git-pull-ff--$TS--2--afterMasterBranch" || true

[ x"$currentbranch" != x -a "$currentbranch" != master ] && \
    git checkout $currentbranch && \
    git pull --ff-only --all && \
    git pull --ff-only --all --recurse-submodules=yes
#    git pull --ff-only $currentbranch && \
#    git pull --ff-only --all

echo "DONE!"
[ x"$currentbranch" != x ] && \
    echo "Started repo '`pwd`' from branch '$currentbranch'... still there?"
git branch

echo "NOTE: Clearing the trap for critical segment"
trap "-" 1 2 3 15

[ -d "$repodir/.zfs/snapshot" ] && \
    mkdir "$repodir/.zfs/snapshot/git-pull-ff--$TS--3--afterCurrentBranch" || true

git pull

[ -d "$repodir/.zfs/snapshot" ] && \
    mkdir "$repodir/.zfs/snapshot/git-pull-ff--$TS--Z--afterSync" || true
}

git_pull_ff