bash: teach 'git checkout' options
[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_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