git.txt: add missing info about --git-dir command-line option
[git] / 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