contrib/git-resurrect.sh

   1 #!/bin/sh
   2
   3 USAGE="[-a] [-r] [-m] [-t] [-n] [-b <newname>] <name>"
   4 LONG_USAGE="git-resurrect attempts to find traces of a branch tip
   5 called <name>, and tries to resurrect it.  Currently, the reflog is
   6 searched for checkout messages, and with -r also merge messages.  With
   7 -m and -t, the history of all refs is scanned for Merge <name> into
   8 other/Merge <other> into <name> (respectively) commit subjects, which
   9 is rather slow but allows you to resurrect other people's topic
  10 branches."
  11
  12 OPTIONS_KEEPDASHDASH=
  13 OPTIONS_SPEC="\
  14 git resurrect $USAGE
  15 --
  16 b,branch=            save branch as <newname> instead of <name>
  17 a,all                same as -l -r -m -t
  18 k,keep-going         full rev-list scan (instead of first match)
  19 l,reflog             scan reflog for checkouts (enabled by default)
  20 r,reflog-merges      scan for merges recorded in reflog
  21 m,merges             scan for merges into other branches (slow)
  22 t,merge-targets      scan for merges of other branches into <name>
  23 n,dry-run            don't recreate the branch"
  24
  25 . git-sh-setup
  26
  27 search_reflog () {
  28         sed -ne 's~^\([^ ]*\) .*\tcheckout: moving from '"$1"' .*~\1~p' \
  29                 < "$GIT_DIR"/logs/HEAD
  30 }
  31
  32 search_reflog_merges () {
  33         git rev-parse $(
  34                 sed -ne 's~^[^ ]* \([^ ]*\) .*\tmerge '"$1"':.*~\1^2~p' \
  35                         < "$GIT_DIR"/logs/HEAD
  36         )
  37 }
  38
  39 _x40="[0-9a-f][0-9a-f][0-9a-f][0-9a-f][0-9a-f]"
  40 _x40="$_x40$_x40$_x40$_x40$_x40$_x40$_x40$_x40"
  41
  42 search_merges () {
  43         git rev-list --all --grep="Merge branch '$1'" \
  44                 --pretty=tformat:"%P %s" |
  45         sed -ne "/^$_x40 \($_x40\) Merge .*/ {s//\1/p;$early_exit}"
  46 }
  47
  48 search_merge_targets () {
  49         git rev-list --all --grep="Merge branch '[^']*' into $branch\$" \
  50                 --pretty=tformat:"%H %s" --all |
  51         sed -ne "/^\($_x40\) Merge .*/ {s//\1/p;$early_exit} "
  52 }
  53
  54 dry_run=
  55 early_exit=q
  56 scan_reflog=t
  57 scan_reflog_merges=
  58 scan_merges=
  59 scan_merge_targets=
  60 new_name=
  61
  62 while test "$#" != 0; do
  63         case "$1" in
  64             -b|--branch)
  65                 shift
  66                 new_name="$1"
  67                 ;;
  68             -n|--dry-run)
  69                 dry_run=t
  70                 ;;
  71             --no-dry-run)
  72                 dry_run=
  73                 ;;
  74             -k|--keep-going)
  75                 early_exit=
  76                 ;;
  77             --no-keep-going)
  78                 early_exit=q
  79                 ;;
  80             -m|--merges)
  81                 scan_merges=t
  82                 ;;
  83             --no-merges)
  84                 scan_merges=
  85                 ;;
  86             -l|--reflog)
  87                 scan_reflog=t
  88                 ;;
  89             --no-reflog)
  90                 scan_reflog=
  91                 ;;
  92             -r|--reflog_merges)
  93                 scan_reflog_merges=t
  94                 ;;
  95             --no-reflog_merges)
  96                 scan_reflog_merges=
  97                 ;;
  98             -t|--merge-targets)
  99                 scan_merge_targets=t
 100                 ;;
 101             --no-merge-targets)
 102                 scan_merge_targets=
 103                 ;;
 104             -a|--all)
 105                 scan_reflog=t
 106                 scan_reflog_merges=t
 107                 scan_merges=t
 108                 scan_merge_targets=t
 109                 ;;
 110             --)
 111                 shift
 112                 break
 113                 ;;
 114             *)
 115                 usage
 116                 ;;
 117         esac
 118         shift
 119 done
 120
 121 test "$#" = 1 || usage
 122
 123 all_strategies="$scan_reflog$scan_reflog_merges$scan_merges$scan_merge_targets"
 124 if test -z "$all_strategies"; then
 125         die "must enable at least one of -lrmt"
 126 fi
 127
 128 branch="$1"
 129 test -z "$new_name" && new_name="$branch"
 130
 131 if test ! -z "$scan_reflog"; then
 132         if test -r "$GIT_DIR"/logs/HEAD; then
 133                 candidates="$(search_reflog $branch)"
 134         else
 135                 die 'reflog scanning requested, but' \
 136                         '$GIT_DIR/logs/HEAD not readable'
 137         fi
 138 fi
 139 if test ! -z "$scan_reflog_merges"; then
 140         if test -r "$GIT_DIR"/logs/HEAD; then
 141                 candidates="$candidates $(search_reflog_merges $branch)"
 142         else
 143                 die 'reflog scanning requested, but' \
 144                         '$GIT_DIR/logs/HEAD not readable'
 145         fi
 146 fi
 147 if test ! -z "$scan_merges"; then
 148         candidates="$candidates $(search_merges $branch)"
 149 fi
 150 if test ! -z "$scan_merge_targets"; then
 151         candidates="$candidates $(search_merge_targets $branch)"
 152 fi
 153
 154 candidates="$(git rev-parse $candidates | sort -u)"
 155
 156 if test -z "$candidates"; then
 157         hint=
 158         test "z$all_strategies" != "ztttt" \
 159                 && hint=" (maybe try again with -a)"
 160         die "no candidates for $branch found$hint"
 161 fi
 162
 163 echo "** Candidates for $branch **"
 164 for cmt in $candidates; do
 165         git --no-pager log --pretty=tformat:"%ct:%h [%cr] %s" --abbrev-commit -1 $cmt
 166 done \
 167 | sort -n | cut -d: -f2-
 168
 169 newest="$(git rev-list -1 $candidates)"
 170 if test ! -z "$dry_run"; then
 171         printf "** Most recent: "
 172         git --no-pager log -1 --pretty=tformat:"%h %s" $newest
 173 elif ! git rev-parse --verify --quiet $new_name >/dev/null; then
 174         printf "** Restoring $new_name to "
 175         git --no-pager log -1 --pretty=tformat:"%h %s" $newest
 176         git branch $new_name $newest
 177 else
 178         printf "Most recent: "
 179         git --no-pager log -1 --pretty=tformat:"%h %s" $newest
 180         echo "** $new_name already exists, doing nothing"
 181 fi