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