Merge branch 'ab/config-based-hooks-base' into seen
[git] / contrib / subtree / git-subtree.sh
1 #!/bin/sh
2 #
3 # git-subtree.sh: split/join git repositories in subdirectories of this one
4 #
5 # Copyright (C) 2009 Avery Pennarun <apenwarr@gmail.com>
6 #
7
8 if test -z "$GIT_EXEC_PATH" || ! test -f "$GIT_EXEC_PATH/git-sh-setup" || {
9         test "${PATH#"${GIT_EXEC_PATH}:"}" = "$PATH" &&
10         test ! "$GIT_EXEC_PATH" -ef "${PATH%%:*}" 2>/dev/null
11 }
12 then
13         basename=${0##*[/\\]}
14         echo >&2 'It looks like either your git installation or your'
15         echo >&2 'git-subtree installation is broken.'
16         echo >&2
17         echo >&2 "Tips:"
18         echo >&2 " - If \`git --exec-path\` does not print the correct path to"
19         echo >&2 "   your git install directory, then set the GIT_EXEC_PATH"
20         echo >&2 "   environment variable to the correct directory."
21         echo >&2 " - Make sure that your \`$basename\` file is either in your"
22         echo >&2 "   PATH or in your git exec path (\`$(git --exec-path)\`)."
23         echo >&2 " - You should run git-subtree as \`git ${basename#git-}\`,"
24         echo >&2 "   not as \`$basename\`." >&2
25         exit 126
26 fi
27
28 OPTS_SPEC="\
29 git subtree add   --prefix=<prefix> <commit>
30 git subtree add   --prefix=<prefix> <repository> <ref>
31 git subtree merge --prefix=<prefix> <commit>
32 git subtree split --prefix=<prefix> [<commit>]
33 git subtree pull  --prefix=<prefix> <repository> <ref>
34 git subtree push  --prefix=<prefix> <repository> <refspec>
35 --
36 h,help        show the help
37 q             quiet
38 d             show debug messages
39 P,prefix=     the name of the subdir to split out
40  options for 'split' (also: 'push')
41 annotate=     add a prefix to commit message of new commits
42 b,branch=     create a new branch from the split subtree
43 ignore-joins  ignore prior --rejoin commits
44 onto=         try connecting new tree to an existing one
45 rejoin        merge the new branch back into HEAD
46  options for 'add' and 'merge' (also: 'pull', 'split --rejoin', and 'push --rejoin')
47 squash        merge subtree changes as a single commit
48 m,message=    use the given message as the commit message for the merge commit
49 "
50
51 indent=0
52
53 # Usage: debug [MSG...]
54 debug () {
55         if test -n "$arg_debug"
56         then
57                 printf "%$(($indent * 2))s%s\n" '' "$*" >&2
58         fi
59 }
60
61 # Usage: progress [MSG...]
62 progress () {
63         if test -z "$GIT_QUIET"
64         then
65                 if test -z "$arg_debug"
66                 then
67                         # Debug mode is off.
68                         #
69                         # Print one progress line that we keep updating (use
70                         # "\r" to return to the beginning of the line, rather
71                         # than "\n" to start a new line).  This only really
72                         # works when stderr is a terminal.
73                         printf "%s\r" "$*" >&2
74                 else
75                         # Debug mode is on.  The `debug` function is regularly
76                         # printing to stderr.
77                         #
78                         # Don't do the one-line-with-"\r" thing, because on a
79                         # terminal the debug output would overwrite and hide the
80                         # progress output.  Add a "progress:" prefix to make the
81                         # progress output and the debug output easy to
82                         # distinguish.  This ensures maximum readability whether
83                         # stderr is a terminal or a file.
84                         printf "progress: %s\n" "$*" >&2
85                 fi
86         fi
87 }
88
89 # Usage: assert CMD...
90 assert () {
91         if ! "$@"
92         then
93                 die "assertion failed: $*"
94         fi
95 }
96
97 main () {
98         if test $# -eq 0
99         then
100                 set -- -h
101         fi
102         set_args="$(echo "$OPTS_SPEC" | git rev-parse --parseopt -- "$@" || echo exit $?)"
103         eval "$set_args"
104         . git-sh-setup
105         require_work_tree
106
107         # First figure out the command and whether we use --rejoin, so
108         # that we can provide more helpful validation when we do the
109         # "real" flag parsing.
110         arg_split_rejoin=
111         allow_split=
112         allow_addmerge=
113         while test $# -gt 0
114         do
115                 opt="$1"
116                 shift
117                 case "$opt" in
118                         --annotate|-b|-P|-m|--onto)
119                                 shift
120                                 ;;
121                         --rejoin)
122                                 arg_split_rejoin=1
123                                 ;;
124                         --no-rejoin)
125                                 arg_split_rejoin=
126                                 ;;
127                         --)
128                                 break
129                                 ;;
130                 esac
131         done
132         arg_command=$1
133         case "$arg_command" in
134         add|merge|pull)
135                 allow_addmerge=1
136                 ;;
137         split|push)
138                 allow_split=1
139                 allow_addmerge=$arg_split_rejoin
140                 ;;
141         *)
142                 die "Unknown command '$arg_command'"
143                 ;;
144         esac
145         # Reset the arguments array for "real" flag parsing.
146         eval "$set_args"
147
148         # Begin "real" flag parsing.
149         arg_debug=
150         arg_prefix=
151         arg_split_branch=
152         arg_split_onto=
153         arg_split_ignore_joins=
154         arg_split_annotate=
155         arg_addmerge_squash=
156         arg_addmerge_message=
157         while test $# -gt 0
158         do
159                 opt="$1"
160                 shift
161
162                 case "$opt" in
163                 -q)
164                         GIT_QUIET=1
165                         ;;
166                 -d)
167                         arg_debug=1
168                         ;;
169                 --annotate)
170                         test -n "$allow_split" || die "The '$opt' flag does not make sense with 'git subtree $arg_command'."
171                         arg_split_annotate="$1"
172                         shift
173                         ;;
174                 --no-annotate)
175                         test -n "$allow_split" || die "The '$opt' flag does not make sense with 'git subtree $arg_command'."
176                         arg_split_annotate=
177                         ;;
178                 -b)
179                         test -n "$allow_split" || die "The '$opt' flag does not make sense with 'git subtree $arg_command'."
180                         arg_split_branch="$1"
181                         shift
182                         ;;
183                 -P)
184                         arg_prefix="${1%/}"
185                         shift
186                         ;;
187                 -m)
188                         test -n "$allow_addmerge" || die "The '$opt' flag does not make sense with 'git subtree $arg_command'."
189                         arg_addmerge_message="$1"
190                         shift
191                         ;;
192                 --no-prefix)
193                         arg_prefix=
194                         ;;
195                 --onto)
196                         test -n "$allow_split" || die "The '$opt' flag does not make sense with 'git subtree $arg_command'."
197                         arg_split_onto="$1"
198                         shift
199                         ;;
200                 --no-onto)
201                         test -n "$allow_split" || die "The '$opt' flag does not make sense with 'git subtree $arg_command'."
202                         arg_split_onto=
203                         ;;
204                 --rejoin)
205                         test -n "$allow_split" || die "The '$opt' flag does not make sense with 'git subtree $arg_command'."
206                         ;;
207                 --no-rejoin)
208                         test -n "$allow_split" || die "The '$opt' flag does not make sense with 'git subtree $arg_command'."
209                         ;;
210                 --ignore-joins)
211                         test -n "$allow_split" || die "The '$opt' flag does not make sense with 'git subtree $arg_command'."
212                         arg_split_ignore_joins=1
213                         ;;
214                 --no-ignore-joins)
215                         test -n "$allow_split" || die "The '$opt' flag does not make sense with 'git subtree $arg_command'."
216                         arg_split_ignore_joins=
217                         ;;
218                 --squash)
219                         test -n "$allow_addmerge" || die "The '$opt' flag does not make sense with 'git subtree $arg_command'."
220                         arg_addmerge_squash=1
221                         ;;
222                 --no-squash)
223                         test -n "$allow_addmerge" || die "The '$opt' flag does not make sense with 'git subtree $arg_command'."
224                         arg_addmerge_squash=
225                         ;;
226                 --)
227                         break
228                         ;;
229                 *)
230                         die "Unexpected option: $opt"
231                         ;;
232                 esac
233         done
234         shift
235
236         if test -z "$arg_prefix"
237         then
238                 die "You must provide the --prefix option."
239         fi
240
241         case "$arg_command" in
242         add)
243                 test -e "$arg_prefix" &&
244                         die "prefix '$arg_prefix' already exists."
245                 ;;
246         *)
247                 test -e "$arg_prefix" ||
248                         die "'$arg_prefix' does not exist; use 'git subtree add'"
249                 ;;
250         esac
251
252         dir="$(dirname "$arg_prefix/.")"
253
254         debug "command: {$arg_command}"
255         debug "quiet: {$GIT_QUIET}"
256         debug "dir: {$dir}"
257         debug "opts: {$*}"
258         debug
259
260         "cmd_$arg_command" "$@"
261 }
262
263 # Usage: cache_setup
264 cache_setup () {
265         assert test $# = 0
266         cachedir="$GIT_DIR/subtree-cache/$$"
267         rm -rf "$cachedir" ||
268                 die "Can't delete old cachedir: $cachedir"
269         mkdir -p "$cachedir" ||
270                 die "Can't create new cachedir: $cachedir"
271         mkdir -p "$cachedir/notree" ||
272                 die "Can't create new cachedir: $cachedir/notree"
273         debug "Using cachedir: $cachedir" >&2
274 }
275
276 # Usage: cache_get [REVS...]
277 cache_get () {
278         for oldrev in "$@"
279         do
280                 if test -r "$cachedir/$oldrev"
281                 then
282                         read newrev <"$cachedir/$oldrev"
283                         echo $newrev
284                 fi
285         done
286 }
287
288 # Usage: cache_miss [REVS...]
289 cache_miss () {
290         for oldrev in "$@"
291         do
292                 if ! test -r "$cachedir/$oldrev"
293                 then
294                         echo $oldrev
295                 fi
296         done
297 }
298
299 # Usage: check_parents PARENTS_EXPR
300 check_parents () {
301         assert test $# = 1
302         missed=$(cache_miss "$1") || exit $?
303         local indent=$(($indent + 1))
304         for miss in $missed
305         do
306                 if ! test -r "$cachedir/notree/$miss"
307                 then
308                         debug "incorrect order: $miss"
309                         process_split_commit "$miss" ""
310                 fi
311         done
312 }
313
314 # Usage: set_notree REV
315 set_notree () {
316         assert test $# = 1
317         echo "1" > "$cachedir/notree/$1"
318 }
319
320 # Usage: cache_set OLDREV NEWREV
321 cache_set () {
322         assert test $# = 2
323         oldrev="$1"
324         newrev="$2"
325         if test "$oldrev" != "latest_old" &&
326                 test "$oldrev" != "latest_new" &&
327                 test -e "$cachedir/$oldrev"
328         then
329                 die "cache for $oldrev already exists!"
330         fi
331         echo "$newrev" >"$cachedir/$oldrev"
332 }
333
334 # Usage: rev_exists REV
335 rev_exists () {
336         assert test $# = 1
337         if git rev-parse "$1" >/dev/null 2>&1
338         then
339                 return 0
340         else
341                 return 1
342         fi
343 }
344
345 # Usage: try_remove_previous REV
346 #
347 # If a commit doesn't have a parent, this might not work.  But we only want
348 # to remove the parent from the rev-list, and since it doesn't exist, it won't
349 # be there anyway, so do nothing in that case.
350 try_remove_previous () {
351         assert test $# = 1
352         if rev_exists "$1^"
353         then
354                 echo "^$1^"
355         fi
356 }
357
358 # Usage: find_latest_squash DIR
359 find_latest_squash () {
360         assert test $# = 1
361         debug "Looking for latest squash ($dir)..."
362         local indent=$(($indent + 1))
363
364         dir="$1"
365         sq=
366         main=
367         sub=
368         git log --grep="^git-subtree-dir: $dir/*\$" \
369                 --no-show-signature --pretty=format:'START %H%n%s%n%n%b%nEND%n' HEAD |
370         while read a b junk
371         do
372                 debug "$a $b $junk"
373                 debug "{{$sq/$main/$sub}}"
374                 case "$a" in
375                 START)
376                         sq="$b"
377                         ;;
378                 git-subtree-mainline:)
379                         main="$b"
380                         ;;
381                 git-subtree-split:)
382                         sub="$(git rev-parse "$b^{commit}")" ||
383                         die "could not rev-parse split hash $b from commit $sq"
384                         ;;
385                 END)
386                         if test -n "$sub"
387                         then
388                                 if test -n "$main"
389                                 then
390                                         # a rejoin commit?
391                                         # Pretend its sub was a squash.
392                                         sq=$(git rev-parse --verify "$sq^2") ||
393                                                 die
394                                 fi
395                                 debug "Squash found: $sq $sub"
396                                 echo "$sq" "$sub"
397                                 break
398                         fi
399                         sq=
400                         main=
401                         sub=
402                         ;;
403                 esac
404         done || exit $?
405 }
406
407 # Usage: find_existing_splits DIR REV
408 find_existing_splits () {
409         assert test $# = 2
410         debug "Looking for prior splits..."
411         local indent=$(($indent + 1))
412
413         dir="$1"
414         rev="$2"
415         main=
416         sub=
417         local grep_format="^git-subtree-dir: $dir/*\$"
418         if test -n "$arg_split_ignore_joins"
419         then
420                 grep_format="^Add '$dir/' from commit '"
421         fi
422         git log --grep="$grep_format" \
423                 --no-show-signature --pretty=format:'START %H%n%s%n%n%b%nEND%n' "$rev" |
424         while read a b junk
425         do
426                 case "$a" in
427                 START)
428                         sq="$b"
429                         ;;
430                 git-subtree-mainline:)
431                         main="$b"
432                         ;;
433                 git-subtree-split:)
434                         sub="$(git rev-parse "$b^{commit}")" ||
435                         die "could not rev-parse split hash $b from commit $sq"
436                         ;;
437                 END)
438                         debug "Main is: '$main'"
439                         if test -z "$main" -a -n "$sub"
440                         then
441                                 # squash commits refer to a subtree
442                                 debug "  Squash: $sq from $sub"
443                                 cache_set "$sq" "$sub"
444                         fi
445                         if test -n "$main" -a -n "$sub"
446                         then
447                                 debug "  Prior: $main -> $sub"
448                                 cache_set $main $sub
449                                 cache_set $sub $sub
450                                 try_remove_previous "$main"
451                                 try_remove_previous "$sub"
452                         fi
453                         main=
454                         sub=
455                         ;;
456                 esac
457         done || exit $?
458 }
459
460 # Usage: copy_commit REV TREE FLAGS_STR
461 copy_commit () {
462         assert test $# = 3
463         # We're going to set some environment vars here, so
464         # do it in a subshell to get rid of them safely later
465         debug copy_commit "{$1}" "{$2}" "{$3}"
466         git log -1 --no-show-signature --pretty=format:'%an%n%ae%n%aD%n%cn%n%ce%n%cD%n%B' "$1" |
467         (
468                 read GIT_AUTHOR_NAME
469                 read GIT_AUTHOR_EMAIL
470                 read GIT_AUTHOR_DATE
471                 read GIT_COMMITTER_NAME
472                 read GIT_COMMITTER_EMAIL
473                 read GIT_COMMITTER_DATE
474                 export  GIT_AUTHOR_NAME \
475                         GIT_AUTHOR_EMAIL \
476                         GIT_AUTHOR_DATE \
477                         GIT_COMMITTER_NAME \
478                         GIT_COMMITTER_EMAIL \
479                         GIT_COMMITTER_DATE
480                 (
481                         printf "%s" "$arg_split_annotate"
482                         cat
483                 ) |
484                 git commit-tree "$2" $3  # reads the rest of stdin
485         ) || die "Can't copy commit $1"
486 }
487
488 # Usage: add_msg DIR LATEST_OLD LATEST_NEW
489 add_msg () {
490         assert test $# = 3
491         dir="$1"
492         latest_old="$2"
493         latest_new="$3"
494         if test -n "$arg_addmerge_message"
495         then
496                 commit_message="$arg_addmerge_message"
497         else
498                 commit_message="Add '$dir/' from commit '$latest_new'"
499         fi
500         if test -n "$arg_split_rejoin"
501         then
502                 # If this is from a --rejoin, then rejoin_msg has
503                 # already inserted the `git-subtree-xxx:` tags
504                 echo "$commit_message"
505                 return
506         fi
507         cat <<-EOF
508                 $commit_message
509
510                 git-subtree-dir: $dir
511                 git-subtree-mainline: $latest_old
512                 git-subtree-split: $latest_new
513         EOF
514 }
515
516 # Usage: add_squashed_msg REV DIR
517 add_squashed_msg () {
518         assert test $# = 2
519         if test -n "$arg_addmerge_message"
520         then
521                 echo "$arg_addmerge_message"
522         else
523                 echo "Merge commit '$1' as '$2'"
524         fi
525 }
526
527 # Usage: rejoin_msg DIR LATEST_OLD LATEST_NEW
528 rejoin_msg () {
529         assert test $# = 3
530         dir="$1"
531         latest_old="$2"
532         latest_new="$3"
533         if test -n "$arg_addmerge_message"
534         then
535                 commit_message="$arg_addmerge_message"
536         else
537                 commit_message="Split '$dir/' into commit '$latest_new'"
538         fi
539         cat <<-EOF
540                 $commit_message
541
542                 git-subtree-dir: $dir
543                 git-subtree-mainline: $latest_old
544                 git-subtree-split: $latest_new
545         EOF
546 }
547
548 # Usage: squash_msg DIR OLD_SUBTREE_COMMIT NEW_SUBTREE_COMMIT
549 squash_msg () {
550         assert test $# = 3
551         dir="$1"
552         oldsub="$2"
553         newsub="$3"
554         newsub_short=$(git rev-parse --short "$newsub")
555
556         if test -n "$oldsub"
557         then
558                 oldsub_short=$(git rev-parse --short "$oldsub")
559                 echo "Squashed '$dir/' changes from $oldsub_short..$newsub_short"
560                 echo
561                 git log --no-show-signature --pretty=tformat:'%h %s' "$oldsub..$newsub"
562                 git log --no-show-signature --pretty=tformat:'REVERT: %h %s' "$newsub..$oldsub"
563         else
564                 echo "Squashed '$dir/' content from commit $newsub_short"
565         fi
566
567         echo
568         echo "git-subtree-dir: $dir"
569         echo "git-subtree-split: $newsub"
570 }
571
572 # Usage: toptree_for_commit COMMIT
573 toptree_for_commit () {
574         assert test $# = 1
575         commit="$1"
576         git rev-parse --verify "$commit^{tree}" || exit $?
577 }
578
579 # Usage: subtree_for_commit COMMIT DIR
580 subtree_for_commit () {
581         assert test $# = 2
582         commit="$1"
583         dir="$2"
584         git ls-tree "$commit" -- "$dir" |
585         while read mode type tree name
586         do
587                 assert test "$name" = "$dir"
588                 assert test "$type" = "tree" -o "$type" = "commit"
589                 test "$type" = "commit" && continue  # ignore submodules
590                 echo $tree
591                 break
592         done || exit $?
593 }
594
595 # Usage: tree_changed TREE [PARENTS...]
596 tree_changed () {
597         assert test $# -gt 0
598         tree=$1
599         shift
600         if test $# -ne 1
601         then
602                 return 0   # weird parents, consider it changed
603         else
604                 ptree=$(toptree_for_commit $1) || exit $?
605                 if test "$ptree" != "$tree"
606                 then
607                         return 0   # changed
608                 else
609                         return 1   # not changed
610                 fi
611         fi
612 }
613
614 # Usage: new_squash_commit OLD_SQUASHED_COMMIT OLD_NONSQUASHED_COMMIT NEW_NONSQUASHED_COMMIT
615 new_squash_commit () {
616         assert test $# = 3
617         old="$1"
618         oldsub="$2"
619         newsub="$3"
620         tree=$(toptree_for_commit $newsub) || exit $?
621         if test -n "$old"
622         then
623                 squash_msg "$dir" "$oldsub" "$newsub" |
624                 git commit-tree "$tree" -p "$old" || exit $?
625         else
626                 squash_msg "$dir" "" "$newsub" |
627                 git commit-tree "$tree" || exit $?
628         fi
629 }
630
631 # Usage: copy_or_skip REV TREE NEWPARENTS
632 copy_or_skip () {
633         assert test $# = 3
634         rev="$1"
635         tree="$2"
636         newparents="$3"
637         assert test -n "$tree"
638
639         identical=
640         nonidentical=
641         p=
642         gotparents=
643         copycommit=
644         for parent in $newparents
645         do
646                 ptree=$(toptree_for_commit $parent) || exit $?
647                 test -z "$ptree" && continue
648                 if test "$ptree" = "$tree"
649                 then
650                         # an identical parent could be used in place of this rev.
651                         if test -n "$identical"
652                         then
653                                 # if a previous identical parent was found, check whether
654                                 # one is already an ancestor of the other
655                                 mergebase=$(git merge-base $identical $parent)
656                                 if test "$identical" = "$mergebase"
657                                 then
658                                         # current identical commit is an ancestor of parent
659                                         identical="$parent"
660                                 elif test "$parent" != "$mergebase"
661                                 then
662                                         # no common history; commit must be copied
663                                         copycommit=1
664                                 fi
665                         else
666                                 # first identical parent detected
667                                 identical="$parent"
668                         fi
669                 else
670                         nonidentical="$parent"
671                 fi
672
673                 # sometimes both old parents map to the same newparent;
674                 # eliminate duplicates
675                 is_new=1
676                 for gp in $gotparents
677                 do
678                         if test "$gp" = "$parent"
679                         then
680                                 is_new=
681                                 break
682                         fi
683                 done
684                 if test -n "$is_new"
685                 then
686                         gotparents="$gotparents $parent"
687                         p="$p -p $parent"
688                 fi
689         done
690
691         if test -n "$identical" && test -n "$nonidentical"
692         then
693                 extras=$(git rev-list --count $identical..$nonidentical)
694                 if test "$extras" -ne 0
695                 then
696                         # we need to preserve history along the other branch
697                         copycommit=1
698                 fi
699         fi
700         if test -n "$identical" && test -z "$copycommit"
701         then
702                 echo $identical
703         else
704                 copy_commit "$rev" "$tree" "$p" || exit $?
705         fi
706 }
707
708 # Usage: ensure_clean
709 ensure_clean () {
710         assert test $# = 0
711         if ! git diff-index HEAD --exit-code --quiet 2>&1
712         then
713                 die "Working tree has modifications.  Cannot add."
714         fi
715         if ! git diff-index --cached HEAD --exit-code --quiet 2>&1
716         then
717                 die "Index has modifications.  Cannot add."
718         fi
719 }
720
721 # Usage: ensure_valid_ref_format REF
722 ensure_valid_ref_format () {
723         assert test $# = 1
724         git check-ref-format "refs/heads/$1" ||
725                 die "'$1' does not look like a ref"
726 }
727
728 # Usage: process_split_commit REV PARENTS
729 process_split_commit () {
730         assert test $# = 2
731         local rev="$1"
732         local parents="$2"
733
734         if test $indent -eq 0
735         then
736                 revcount=$(($revcount + 1))
737         else
738                 # processing commit without normal parent information;
739                 # fetch from repo
740                 parents=$(git rev-parse "$rev^@")
741                 extracount=$(($extracount + 1))
742         fi
743
744         progress "$revcount/$revmax ($createcount) [$extracount]"
745
746         debug "Processing commit: $rev"
747         local indent=$(($indent + 1))
748         exists=$(cache_get "$rev") || exit $?
749         if test -n "$exists"
750         then
751                 debug "prior: $exists"
752                 return
753         fi
754         createcount=$(($createcount + 1))
755         debug "parents: $parents"
756         check_parents "$parents"
757         newparents=$(cache_get $parents) || exit $?
758         debug "newparents: $newparents"
759
760         tree=$(subtree_for_commit "$rev" "$dir") || exit $?
761         debug "tree is: $tree"
762
763         # ugly.  is there no better way to tell if this is a subtree
764         # vs. a mainline commit?  Does it matter?
765         if test -z "$tree"
766         then
767                 set_notree "$rev"
768                 if test -n "$newparents"
769                 then
770                         cache_set "$rev" "$rev"
771                 fi
772                 return
773         fi
774
775         newrev=$(copy_or_skip "$rev" "$tree" "$newparents") || exit $?
776         debug "newrev is: $newrev"
777         cache_set "$rev" "$newrev"
778         cache_set latest_new "$newrev"
779         cache_set latest_old "$rev"
780 }
781
782 # Usage: cmd_add REV
783 #    Or: cmd_add REPOSITORY REF
784 cmd_add () {
785
786         ensure_clean
787
788         if test $# -eq 1
789         then
790                 git rev-parse -q --verify "$1^{commit}" >/dev/null ||
791                         die "'$1' does not refer to a commit"
792
793                 cmd_add_commit "$@"
794
795         elif test $# -eq 2
796         then
797                 # Technically we could accept a refspec here but we're
798                 # just going to turn around and add FETCH_HEAD under the
799                 # specified directory.  Allowing a refspec might be
800                 # misleading because we won't do anything with any other
801                 # branches fetched via the refspec.
802                 ensure_valid_ref_format "$2"
803
804                 cmd_add_repository "$@"
805         else
806                 say >&2 "error: parameters were '$*'"
807                 die "Provide either a commit or a repository and commit."
808         fi
809 }
810
811 # Usage: cmd_add_repository REPOSITORY REFSPEC
812 cmd_add_repository () {
813         assert test $# = 2
814         echo "git fetch" "$@"
815         repository=$1
816         refspec=$2
817         git fetch "$@" || exit $?
818         cmd_add_commit FETCH_HEAD
819 }
820
821 # Usage: cmd_add_commit REV
822 cmd_add_commit () {
823         # The rev has already been validated by cmd_add(), we just
824         # need to normalize it.
825         assert test $# = 1
826         rev=$(git rev-parse --verify "$1^{commit}") || exit $?
827
828         debug "Adding $dir as '$rev'..."
829         if test -z "$arg_split_rejoin"
830         then
831                 # Only bother doing this if this is a genuine 'add',
832                 # not a synthetic 'add' from '--rejoin'.
833                 git read-tree --prefix="$dir" $rev || exit $?
834         fi
835         git checkout -- "$dir" || exit $?
836         tree=$(git write-tree) || exit $?
837
838         headrev=$(git rev-parse HEAD) || exit $?
839         if test -n "$headrev" && test "$headrev" != "$rev"
840         then
841                 headp="-p $headrev"
842         else
843                 headp=
844         fi
845
846         if test -n "$arg_addmerge_squash"
847         then
848                 rev=$(new_squash_commit "" "" "$rev") || exit $?
849                 commit=$(add_squashed_msg "$rev" "$dir" |
850                         git commit-tree "$tree" $headp -p "$rev") || exit $?
851         else
852                 revp=$(peel_committish "$rev") || exit $?
853                 commit=$(add_msg "$dir" $headrev "$rev" |
854                         git commit-tree "$tree" $headp -p "$revp") || exit $?
855         fi
856         git reset "$commit" || exit $?
857
858         say >&2 "Added dir '$dir'"
859 }
860
861 # Usage: cmd_split [REV]
862 cmd_split () {
863         if test $# -eq 0
864         then
865                 rev=$(git rev-parse HEAD)
866         elif test $# -eq 1
867         then
868                 rev=$(git rev-parse -q --verify "$1^{commit}") ||
869                         die "'$1' does not refer to a commit"
870         else
871                 die "You must provide exactly one revision.  Got: '$*'"
872         fi
873
874         if test -n "$arg_split_rejoin"
875         then
876                 ensure_clean
877         fi
878
879         debug "Splitting $dir..."
880         cache_setup || exit $?
881
882         if test -n "$arg_split_onto"
883         then
884                 debug "Reading history for --onto=$arg_split_onto..."
885                 git rev-list $arg_split_onto |
886                 while read rev
887                 do
888                         # the 'onto' history is already just the subdir, so
889                         # any parent we find there can be used verbatim
890                         debug "cache: $rev"
891                         cache_set "$rev" "$rev"
892                 done || exit $?
893         fi
894
895         unrevs="$(find_existing_splits "$dir" "$rev")" || exit $?
896
897         # We can't restrict rev-list to only $dir here, because some of our
898         # parents have the $dir contents the root, and those won't match.
899         # (and rev-list --follow doesn't seem to solve this)
900         grl='git rev-list --topo-order --reverse --parents $rev $unrevs'
901         revmax=$(eval "$grl" | wc -l)
902         revcount=0
903         createcount=0
904         extracount=0
905         eval "$grl" |
906         while read rev parents
907         do
908                 process_split_commit "$rev" "$parents"
909         done || exit $?
910
911         latest_new=$(cache_get latest_new) || exit $?
912         if test -z "$latest_new"
913         then
914                 die "No new revisions were found"
915         fi
916
917         if test -n "$arg_split_rejoin"
918         then
919                 debug "Merging split branch into HEAD..."
920                 latest_old=$(cache_get latest_old) || exit $?
921                 arg_addmerge_message="$(rejoin_msg "$dir" "$latest_old" "$latest_new")" || exit $?
922                 if test -z "$(find_latest_squash "$dir")"
923                 then
924                         cmd_add "$latest_new" >&2 || exit $?
925                 else
926                         cmd_merge "$latest_new" >&2 || exit $?
927                 fi
928         fi
929         if test -n "$arg_split_branch"
930         then
931                 if rev_exists "refs/heads/$arg_split_branch"
932                 then
933                         if ! git merge-base --is-ancestor "$arg_split_branch" "$latest_new"
934                         then
935                                 die "Branch '$arg_split_branch' is not an ancestor of commit '$latest_new'."
936                         fi
937                         action='Updated'
938                 else
939                         action='Created'
940                 fi
941                 git update-ref -m 'subtree split' \
942                         "refs/heads/$arg_split_branch" "$latest_new" || exit $?
943                 say >&2 "$action branch '$arg_split_branch'"
944         fi
945         echo "$latest_new"
946         exit 0
947 }
948
949 # Usage: cmd_merge REV
950 cmd_merge () {
951         test $# -eq 1 ||
952                 die "You must provide exactly one revision.  Got: '$*'"
953         rev=$(git rev-parse -q --verify "$1^{commit}") ||
954                 die "'$1' does not refer to a commit"
955         ensure_clean
956
957         if test -n "$arg_addmerge_squash"
958         then
959                 first_split="$(find_latest_squash "$dir")" || exit $?
960                 if test -z "$first_split"
961                 then
962                         die "Can't squash-merge: '$dir' was never added."
963                 fi
964                 set $first_split
965                 old=$1
966                 sub=$2
967                 if test "$sub" = "$rev"
968                 then
969                         say >&2 "Subtree is already at commit $rev."
970                         exit 0
971                 fi
972                 new=$(new_squash_commit "$old" "$sub" "$rev") || exit $?
973                 debug "New squash commit: $new"
974                 rev="$new"
975         fi
976
977         if test -n "$arg_addmerge_message"
978         then
979                 git merge -Xsubtree="$arg_prefix" \
980                         --message="$arg_addmerge_message" "$rev"
981         else
982                 git merge -Xsubtree="$arg_prefix" $rev
983         fi
984 }
985
986 # Usage: cmd_pull REPOSITORY REMOTEREF
987 cmd_pull () {
988         if test $# -ne 2
989         then
990                 die "You must provide <repository> <ref>"
991         fi
992         ensure_clean
993         ensure_valid_ref_format "$2"
994         git fetch "$@" || exit $?
995         cmd_merge FETCH_HEAD
996 }
997
998 # Usage: cmd_push REPOSITORY [+][LOCALREV:]REMOTEREF
999 cmd_push () {
1000         if test $# -ne 2
1001         then
1002                 die "You must provide <repository> <refspec>"
1003         fi
1004         if test -e "$dir"
1005         then
1006                 repository=$1
1007                 refspec=${2#+}
1008                 remoteref=${refspec#*:}
1009                 if test "$remoteref" = "$refspec"
1010                 then
1011                         localrevname_presplit=HEAD
1012                 else
1013                         localrevname_presplit=${refspec%%:*}
1014                 fi
1015                 ensure_valid_ref_format "$remoteref"
1016                 localrev_presplit=$(git rev-parse -q --verify "$localrevname_presplit^{commit}") ||
1017                         die "'$localrevname_presplit' does not refer to a commit"
1018
1019                 echo "git push using: " "$repository" "$refspec"
1020                 localrev=$(cmd_split "$localrev_presplit") || die
1021                 git push "$repository" "$localrev":"refs/heads/$remoteref"
1022         else
1023                 die "'$dir' must already exist. Try 'git subtree add'."
1024         fi
1025 }
1026
1027 main "$@"