contrib git-resurrect: find traces of a branch name and resurrect it
Add a tool 'git-resurrect.sh <branch>' that tries to find traces of the <branch> in the HEAD reflog and, optionally, all merge commits in the repository. It can then resurrect the branch, pointing it at the most recent of all candidate commits found. Signed-off-by: Thomas Rast <trast@student.ethz.ch> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Thomas Rast committed
Feb 4, 2009 at 11:04 UTC
e1ff064e1bffedb917c491681b7bfd4d66633ef5
1 file changed
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contrib/git-resurrect.sh
new
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+#!/bin/sh
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+
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+USAGE="[-a] [-r] [-m] [-t] [-n] [-b <newname>] <name>"
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+LONG_USAGE="git-resurrect attempts to find traces of a branch tip
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+called <name>, and tries to resurrect it. Currently, the reflog is
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+searched for checkout messages, and with -r also merge messages. With
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+-m and -t, the history of all refs is scanned for Merge <name> into
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+other/Merge <other> into <name> (respectively) commit subjects, which
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+is rather slow but allows you to resurrect other people's topic
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+branches."
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+
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+OPTIONS_SPEC="\
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+git resurrect $USAGE
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+--
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+b,branch= save branch as <newname> instead of <name>
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+a,all same as -l -r -m -t
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+k,keep-going full rev-list scan (instead of first match)
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+l,reflog scan reflog for checkouts (enabled by default)
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+r,reflog-merges scan for merges recorded in reflog
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+m,merges scan for merges into other branches (slow)
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+t,merge-targets scan for merges of other branches into <name>
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+n,dry-run don't recreate the branch"
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+
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+. git-sh-setup
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+
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+search_reflog () {
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+ sed -ne 's~^\([^ ]*\) .*\tcheckout: moving from '"$1"' .*~\1~p' \
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+ < "$GIT_DIR"/logs/HEAD
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+}
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+
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+search_reflog_merges () {
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+ git rev-parse $(
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+ sed -ne 's~^[^ ]* \([^ ]*\) .*\tmerge '"$1"':.*~\1^2~p' \
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+ < "$GIT_DIR"/logs/HEAD
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+ )
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+}
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+
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+_x40="[0-9a-f][0-9a-f][0-9a-f][0-9a-f][0-9a-f]"
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+_x40="$_x40$_x40$_x40$_x40$_x40$_x40$_x40$_x40"
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+
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+search_merges () {
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+ git rev-list --all --grep="Merge branch '$1'" \
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+ --pretty=tformat:"%P %s" |
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+ sed -ne "/^$_x40 \($_x40\) Merge .*/ {s//\1/p;$early_exit}"
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+}
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+
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+search_merge_targets () {
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+ git rev-list --all --grep="Merge branch '[^']*' into $branch\$" \
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+ --pretty=tformat:"%H %s" --all |
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+ sed -ne "/^\($_x40\) Merge .*/ {s//\1/p;$early_exit} "
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+}
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+
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+dry_run=
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+early_exit=q
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+scan_reflog=t
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+scan_reflog_merges=
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+scan_merges=
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+scan_merge_targets=
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+new_name=
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+
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+while test "$#" != 0; do
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+ case "$1" in
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+ -b|--branch)
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+ shift
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+ new_name="$1"
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+ ;;
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+ -n|--dry-run)
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+ dry_run=t
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+ ;;
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+ --no-dry-run)
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+ dry_run=
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+ ;;
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+ -k|--keep-going)
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+ early_exit=
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+ ;;
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+ --no-keep-going)
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+ early_exit=q
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+ ;;
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+ -m|--merges)
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+ scan_merges=t
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+ ;;
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+ --no-merges)
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+ scan_merges=
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+ ;;
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+ -l|--reflog)
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+ scan_reflog=t
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+ ;;
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+ --no-reflog)
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+ scan_reflog=
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+ ;;
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+ -r|--reflog_merges)
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+ scan_reflog_merges=t
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+ ;;
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+ --no-reflog_merges)
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+ scan_reflog_merges=
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+ ;;
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+ -t|--merge-targets)
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+ scan_merge_targets=t
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+ ;;
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+ --no-merge-targets)
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+ scan_merge_targets=
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+ ;;
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+ -a|--all)
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+ scan_reflog=t
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+ scan_reflog_merges=t
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+ scan_merges=t
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+ scan_merge_targets=t
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+ ;;
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+ --)
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+ shift
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+ break
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+ ;;
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+ *)
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+ usage
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+ ;;
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+ esac
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+ shift
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+done
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+
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+test "$#" = 1 || usage
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+
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+all_strategies="$scan_reflog$scan_reflog_merges$scan_merges$scan_merge_targets"
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+if test -z "$all_strategies"; then
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+ die "must enable at least one of -lrmt"
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+fi
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+
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+branch="$1"
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+test -z "$new_name" && new_name="$branch"
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+
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+if test ! -z "$scan_reflog"; then
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+ if test -r "$GIT_DIR"/logs/HEAD; then
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+ candidates="$(search_reflog $branch)"
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+ else
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+ die 'reflog scanning requested, but' \
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+ '$GIT_DIR/logs/HEAD not readable'
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+ fi
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+fi
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+if test ! -z "$scan_reflog_merges"; then
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+ if test -r "$GIT_DIR"/logs/HEAD; then
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+ candidates="$candidates $(search_reflog_merges $branch)"
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+ else
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+ die 'reflog scanning requested, but' \
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+ '$GIT_DIR/logs/HEAD not readable'
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+ fi
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+fi
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+if test ! -z "$scan_merges"; then
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+ candidates="$candidates $(search_merges $branch)"
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+fi
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+if test ! -z "$scan_merge_targets"; then
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+ candidates="$candidates $(search_merge_targets $branch)"
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+fi
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+
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+candidates="$(git rev-parse $candidates | sort -u)"
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+
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+if test -z "$candidates"; then
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+ hint=
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+ test "z$all_strategies" != "ztttt" \
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+ && hint=" (maybe try again with -a)"
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+ die "no candidates for $branch found$hint"
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+fi
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+
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+echo "** Candidates for $branch **"
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+for cmt in $candidates; do
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+ git --no-pager log --pretty=tformat:"%ct:%h [%cr] %s" --abbrev-commit -1 $cmt
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+done \
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+| sort -n | cut -d: -f2-
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+
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+newest="$(git rev-list -1 $candidates)"
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+if test ! -z "$dry_run"; then
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+ printf "** Most recent: "
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+ git --no-pager log -1 --pretty=tformat:"%h %s" $newest
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+elif ! git rev-parse --verify --quiet $new_name >/dev/null; then
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+ printf "** Restoring $new_name to "
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+ git --no-pager log -1 --pretty=tformat:"%h %s" $newest
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+ git branch $new_name $newest
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+else
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+ printf "Most recent: "
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+ git --no-pager log -1 --pretty=tformat:"%h %s" $newest
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+ echo "** $new_name already exists, doing nothing"
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+fi