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#!/bin/sh
#
# git-subtree.sh: split/join git repositories in subdirectories of this one
#
# Copyright (C) 2009 Avery Pennarun <apenwarr@gmail.com>
#
if test $# -eq 0
then
set -- -h
fi
OPTS_SPEC="\
git subtree add --prefix=<prefix> <commit>
git subtree add --prefix=<prefix> <repository> <ref>
git subtree merge --prefix=<prefix> <commit>
git subtree pull --prefix=<prefix> <repository> <ref>
git subtree push --prefix=<prefix> <repository> <ref>
git subtree split --prefix=<prefix> <commit>
--
h,help show the help
q quiet
d show debug messages
P,prefix= the name of the subdir to split out
m,message= use the given message as the commit message for the merge commit
options for 'split'
annotate= add a prefix to commit message of new commits
b,branch= create a new branch from the split subtree
ignore-joins ignore prior --rejoin commits
onto= try connecting new tree to an existing one
rejoin merge the new branch back into HEAD
options for 'add', 'merge', and 'pull'
squash merge subtree changes as a single commit
"
eval "$(echo "$OPTS_SPEC" | git rev-parse --parseopt -- "$@" || echo exit $?)"
PATH=$PATH:$(git --exec-path)
. git-sh-setup
require_work_tree
quiet=
branch=
debug=
command=
onto=
rejoin=
ignore_joins=
annotate=
squash=
message=
prefix=
debug () {
if test -n "$debug"
then
printf "%s\n" "$*" >&2
fi
}
say () {
if test -z "$quiet"
then
printf "%s\n" "$*" >&2
fi
}
progress () {
if test -z "$quiet"
then
printf "%s\r" "$*" >&2
fi
}
assert () {
if ! "$@"
then
die "assertion failed: " "$@"
fi
}
ensure_single_rev () {
if test $# -ne 1
then
die "You must provide exactly one revision. Got: '$@'"
fi
}
while test $# -gt 0
do
opt="$1"
shift
case "$opt" in
-q)
quiet=1
;;
-d)
debug=1
;;
--annotate)
annotate="$1"
shift
;;
--no-annotate)
annotate=
;;
-b)
branch="$1"
shift
;;
-P)
prefix="${1%/}"
shift
;;
-m)
message="$1"
shift
;;
--no-prefix)
prefix=
;;
--onto)
onto="$1"
shift
;;
--no-onto)
onto=
;;
--rejoin)
rejoin=1
;;
--no-rejoin)
rejoin=
;;
--ignore-joins)
ignore_joins=1
;;
--no-ignore-joins)
ignore_joins=
;;
--squash)
squash=1
;;
--no-squash)
squash=
;;
--)
break
;;
*)
die "Unexpected option: $opt"
;;
esac
done
command="$1"
shift
case "$command" in
add|merge|pull)
default=
;;
split|push)
default="--default HEAD"
;;
*)
die "Unknown command '$command'"
;;
esac
if test -z "$prefix"
then
die "You must provide the --prefix option."
fi
case "$command" in
add)
test -e "$prefix" &&
die "prefix '$prefix' already exists."
;;
*)
test -e "$prefix" ||
die "'$prefix' does not exist; use 'git subtree add'"
;;
esac
dir="$(dirname "$prefix/.")"
if test "$command" != "pull" &&
test "$command" != "add" &&
test "$command" != "push"
then
revs=$(git rev-parse $default --revs-only "$@") || exit $?
dirs=$(git rev-parse --no-revs --no-flags "$@") || exit $?
ensure_single_rev $revs
if test -n "$dirs"
then
die "Error: Use --prefix instead of bare filenames."
fi
fi
debug "command: {$command}"
debug "quiet: {$quiet}"
debug "revs: {$revs}"
debug "dir: {$dir}"
debug "opts: {$*}"
debug
cache_setup () {
cachedir="$GIT_DIR/subtree-cache/$$"
rm -rf "$cachedir" ||
die "Can't delete old cachedir: $cachedir"
mkdir -p "$cachedir" ||
die "Can't create new cachedir: $cachedir"
mkdir -p "$cachedir/notree" ||
die "Can't create new cachedir: $cachedir/notree"
debug "Using cachedir: $cachedir" >&2
}
cache_get () {
for oldrev in "$@"
do
if test -r "$cachedir/$oldrev"
then
read newrev <"$cachedir/$oldrev"
echo $newrev
fi
done
}
cache_miss () {
for oldrev in "$@"
do
if ! test -r "$cachedir/$oldrev"
then
echo $oldrev
fi
done
}
check_parents () {
missed=$(cache_miss "$1")
local indent=$(($2 + 1))
for miss in $missed
do
if ! test -r "$cachedir/notree/$miss"
then
debug " incorrect order: $miss"
process_split_commit "$miss" "" "$indent"
fi
done
}
set_notree () {
echo "1" > "$cachedir/notree/$1"
}
cache_set () {
oldrev="$1"
newrev="$2"
if test "$oldrev" != "latest_old" &&
test "$oldrev" != "latest_new" &&
test -e "$cachedir/$oldrev"
then
die "cache for $oldrev already exists!"
fi
echo "$newrev" >"$cachedir/$oldrev"
}
rev_exists () {
if git rev-parse "$1" >/dev/null 2>&1
then
return 0
else
return 1
fi
}
rev_is_descendant_of_branch () {
newrev="$1"
branch="$2"
branch_hash=$(git rev-parse "$branch")
match=$(git rev-list -1 "$branch_hash" "^$newrev")
if test -z "$match"
then
return 0
else
return 1
fi
}
# if a commit doesn't have a parent, this might not work. But we only want
# to remove the parent from the rev-list, and since it doesn't exist, it won't
# be there anyway, so do nothing in that case.
try_remove_previous () {
if rev_exists "$1^"
then
echo "^$1^"
fi
}
find_latest_squash () {
debug "Looking for latest squash ($dir)..."
dir="$1"
sq=
main=
sub=
git log --grep="^git-subtree-dir: $dir/*\$" \
--no-show-signature --pretty=format:'START %H%n%s%n%n%b%nEND%n' HEAD |
while read a b junk
do
debug "$a $b $junk"
debug "{{$sq/$main/$sub}}"
case "$a" in
START)
sq="$b"
;;
git-subtree-mainline:)
main="$b"
;;
git-subtree-split:)
sub="$(git rev-parse "$b^0")" ||
die "could not rev-parse split hash $b from commit $sq"
;;
END)
if test -n "$sub"
then
if test -n "$main"
then
# a rejoin commit?
# Pretend its sub was a squash.
sq="$sub"
fi
debug "Squash found: $sq $sub"
echo "$sq" "$sub"
break
fi
sq=
main=
sub=
;;
esac
done
}
find_existing_splits () {
debug "Looking for prior splits..."
dir="$1"
revs="$2"
main=
sub=
local grep_format="^git-subtree-dir: $dir/*\$"
if test -n "$ignore_joins"
then
grep_format="^Add '$dir/' from commit '"
fi
git log --grep="$grep_format" \
--no-show-signature --pretty=format:'START %H%n%s%n%n%b%nEND%n' $revs |
while read a b junk
do
case "$a" in
START)
sq="$b"
;;
git-subtree-mainline:)
main="$b"
;;
git-subtree-split:)
sub="$(git rev-parse "$b^0")" ||
die "could not rev-parse split hash $b from commit $sq"
;;
END)
debug " Main is: '$main'"
if test -z "$main" -a -n "$sub"
then
# squash commits refer to a subtree
debug " Squash: $sq from $sub"
cache_set "$sq" "$sub"
fi
if test -n "$main" -a -n "$sub"
then
debug " Prior: $main -> $sub"
cache_set $main $sub
cache_set $sub $sub
try_remove_previous "$main"
try_remove_previous "$sub"
fi
main=
sub=
;;
esac
done
}
copy_commit () {
# We're going to set some environment vars here, so
# do it in a subshell to get rid of them safely later
debug copy_commit "{$1}" "{$2}" "{$3}"
git log -1 --no-show-signature --pretty=format:'%an%n%ae%n%aD%n%cn%n%ce%n%cD%n%B' "$1" |
(
read GIT_AUTHOR_NAME
read GIT_AUTHOR_EMAIL
read GIT_AUTHOR_DATE
read GIT_COMMITTER_NAME
read GIT_COMMITTER_EMAIL
read GIT_COMMITTER_DATE
export GIT_AUTHOR_NAME \
GIT_AUTHOR_EMAIL \
GIT_AUTHOR_DATE \
GIT_COMMITTER_NAME \
GIT_COMMITTER_EMAIL \
GIT_COMMITTER_DATE
(
printf "%s" "$annotate"
cat
) |
git commit-tree "$2" $3 # reads the rest of stdin
) || die "Can't copy commit $1"
}
add_msg () {
dir="$1"
latest_old="$2"
latest_new="$3"
if test -n "$message"
then
commit_message="$message"
else
commit_message="Add '$dir/' from commit '$latest_new'"
fi
cat <<-EOF
$commit_message
git-subtree-dir: $dir
git-subtree-mainline: $latest_old
git-subtree-split: $latest_new
EOF
}
add_squashed_msg () {
if test -n "$message"
then
echo "$message"
else
echo "Merge commit '$1' as '$2'"
fi
}
rejoin_msg () {
dir="$1"
latest_old="$2"
latest_new="$3"
if test -n "$message"
then
commit_message="$message"
else
commit_message="Split '$dir/' into commit '$latest_new'"
fi
cat <<-EOF
$commit_message
git-subtree-dir: $dir
git-subtree-mainline: $latest_old
git-subtree-split: $latest_new
EOF
}
squash_msg () {
dir="$1"
oldsub="$2"
newsub="$3"
newsub_short=$(git rev-parse --short "$newsub")
if test -n "$oldsub"
then
oldsub_short=$(git rev-parse --short "$oldsub")
echo "Squashed '$dir/' changes from $oldsub_short..$newsub_short"
echo
git log --no-show-signature --pretty=tformat:'%h %s' "$oldsub..$newsub"
git log --no-show-signature --pretty=tformat:'REVERT: %h %s' "$newsub..$oldsub"
else
echo "Squashed '$dir/' content from commit $newsub_short"
fi
echo
echo "git-subtree-dir: $dir"
echo "git-subtree-split: $newsub"
}
toptree_for_commit () {
commit="$1"
git rev-parse --verify "$commit^{tree}" || exit $?
}
subtree_for_commit () {
commit="$1"
dir="$2"
git ls-tree "$commit" -- "$dir" |
while read mode type tree name
do
assert test "$name" = "$dir"
assert test "$type" = "tree" -o "$type" = "commit"
test "$type" = "commit" && continue # ignore submodules
echo $tree
break
done
}
tree_changed () {
tree=$1
shift
if test $# -ne 1
then
return 0 # weird parents, consider it changed
else
ptree=$(toptree_for_commit $1)
if test "$ptree" != "$tree"
then
return 0 # changed
else
return 1 # not changed
fi
fi
}
new_squash_commit () {
old="$1"
oldsub="$2"
newsub="$3"
tree=$(toptree_for_commit $newsub) || exit $?
if test -n "$old"
then
squash_msg "$dir" "$oldsub" "$newsub" |
git commit-tree "$tree" -p "$old" || exit $?
else
squash_msg "$dir" "" "$newsub" |
git commit-tree "$tree" || exit $?
fi
}
copy_or_skip () {
rev="$1"
tree="$2"
newparents="$3"
assert test -n "$tree"
identical=
nonidentical=
p=
gotparents=
copycommit=
for parent in $newparents
do
ptree=$(toptree_for_commit $parent) || exit $?
test -z "$ptree" && continue
if test "$ptree" = "$tree"
then
# an identical parent could be used in place of this rev.
if test -n "$identical"
then
# if a previous identical parent was found, check whether
# one is already an ancestor of the other
mergebase=$(git merge-base $identical $parent)
if test "$identical" = "$mergebase"
then
# current identical commit is an ancestor of parent
identical="$parent"
elif test "$parent" != "$mergebase"
then
# no common history; commit must be copied
copycommit=1
fi
else
# first identical parent detected
identical="$parent"
fi
else
nonidentical="$parent"
fi
# sometimes both old parents map to the same newparent;
# eliminate duplicates
is_new=1
for gp in $gotparents
do
if test "$gp" = "$parent"
then
is_new=
break
fi
done
if test -n "$is_new"
then
gotparents="$gotparents $parent"
p="$p -p $parent"
fi
done
if test -n "$identical" && test -n "$nonidentical"
then
extras=$(git rev-list --count $identical..$nonidentical)
if test "$extras" -ne 0
then
# we need to preserve history along the other branch
copycommit=1
fi
fi
if test -n "$identical" && test -z "$copycommit"
then
echo $identical
else
copy_commit "$rev" "$tree" "$p" || exit $?
fi
}
ensure_clean () {
if ! git diff-index HEAD --exit-code --quiet 2>&1
then
die "Working tree has modifications. Cannot add."
fi
if ! git diff-index --cached HEAD --exit-code --quiet 2>&1
then
die "Index has modifications. Cannot add."
fi
}
ensure_valid_ref_format () {
git check-ref-format "refs/heads/$1" ||
die "'$1' does not look like a ref"
}
process_split_commit () {
local rev="$1"
local parents="$2"
local indent=$3
if test $indent -eq 0
then
revcount=$(($revcount + 1))
else
# processing commit without normal parent information;
# fetch from repo
parents=$(git rev-parse "$rev^@")
extracount=$(($extracount + 1))
fi
progress "$revcount/$revmax ($createcount) [$extracount]"
debug "Processing commit: $rev"
exists=$(cache_get "$rev")
if test -n "$exists"
then
debug " prior: $exists"
return
fi
createcount=$(($createcount + 1))
debug " parents: $parents"
check_parents "$parents" "$indent"
newparents=$(cache_get $parents)
debug " newparents: $newparents"
tree=$(subtree_for_commit "$rev" "$dir")
debug " tree is: $tree"
# ugly. is there no better way to tell if this is a subtree
# vs. a mainline commit? Does it matter?
if test -z "$tree"
then
set_notree "$rev"
if test -n "$newparents"
then
cache_set "$rev" "$rev"
fi
return
fi
newrev=$(copy_or_skip "$rev" "$tree" "$newparents") || exit $?
debug " newrev is: $newrev"
cache_set "$rev" "$newrev"
cache_set latest_new "$newrev"
cache_set latest_old "$rev"
}
cmd_add () {
if test -e "$dir"
then
die "'$dir' already exists. Cannot add."
fi
ensure_clean
if test $# -eq 1
then
git rev-parse -q --verify "$1^{commit}" >/dev/null ||
die "'$1' does not refer to a commit"
cmd_add_commit "$@"
elif test $# -eq 2
then
# Technically we could accept a refspec here but we're
# just going to turn around and add FETCH_HEAD under the
# specified directory. Allowing a refspec might be
# misleading because we won't do anything with any other
# branches fetched via the refspec.
ensure_valid_ref_format "$2"
cmd_add_repository "$@"
else
say "error: parameters were '$@'"
die "Provide either a commit or a repository and commit."
fi
}
cmd_add_repository () {
echo "git fetch" "$@"
repository=$1
refspec=$2
git fetch "$@" || exit $?
revs=FETCH_HEAD
set -- $revs
cmd_add_commit "$@"
}
cmd_add_commit () {
rev=$(git rev-parse $default --revs-only "$@") || exit $?
ensure_single_rev $rev
debug "Adding $dir as '$rev'..."
git read-tree --prefix="$dir" $rev || exit $?
git checkout -- "$dir" || exit $?
tree=$(git write-tree) || exit $?
headrev=$(git rev-parse HEAD) || exit $?
if test -n "$headrev" && test "$headrev" != "$rev"
then
headp="-p $headrev"
else
headp=
fi
if test -n "$squash"
then
rev=$(new_squash_commit "" "" "$rev") || exit $?
commit=$(add_squashed_msg "$rev" "$dir" |
git commit-tree "$tree" $headp -p "$rev") || exit $?
else
revp=$(peel_committish "$rev") &&
commit=$(add_msg "$dir" $headrev "$rev" |
git commit-tree "$tree" $headp -p "$revp") || exit $?
fi
git reset "$commit" || exit $?
say "Added dir '$dir'"
}
cmd_split () {
debug "Splitting $dir..."
cache_setup || exit $?
if test -n "$onto"
then
debug "Reading history for --onto=$onto..."
git rev-list $onto |
while read rev
do
# the 'onto' history is already just the subdir, so
# any parent we find there can be used verbatim
debug " cache: $rev"
cache_set "$rev" "$rev"
done
fi
unrevs="$(find_existing_splits "$dir" "$revs")"
# We can't restrict rev-list to only $dir here, because some of our
# parents have the $dir contents the root, and those won't match.
# (and rev-list --follow doesn't seem to solve this)
grl='git rev-list --topo-order --reverse --parents $revs $unrevs'
revmax=$(eval "$grl" | wc -l)
revcount=0
createcount=0
extracount=0
eval "$grl" |
while read rev parents
do
process_split_commit "$rev" "$parents" 0
done || exit $?
latest_new=$(cache_get latest_new)
if test -z "$latest_new"
then
die "No new revisions were found"
fi
if test -n "$rejoin"
then
debug "Merging split branch into HEAD..."
latest_old=$(cache_get latest_old)
git merge -s ours \
--allow-unrelated-histories \
-m "$(rejoin_msg "$dir" "$latest_old" "$latest_new")" \
"$latest_new" >&2 || exit $?
fi
if test -n "$branch"
then
if rev_exists "refs/heads/$branch"
then
if ! rev_is_descendant_of_branch "$latest_new" "$branch"
then
die "Branch '$branch' is not an ancestor of commit '$latest_new'."
fi
action='Updated'
else
action='Created'
fi
git update-ref -m 'subtree split' \
"refs/heads/$branch" "$latest_new" || exit $?
say "$action branch '$branch'"
fi
echo "$latest_new"
exit 0
}
cmd_merge () {
rev=$(git rev-parse $default --revs-only "$@") || exit $?
ensure_single_rev $rev
ensure_clean
if test -n "$squash"
then
first_split="$(find_latest_squash "$dir")"
if test -z "$first_split"
then
die "Can't squash-merge: '$dir' was never added."
fi
set $first_split
old=$1
sub=$2
if test "$sub" = "$rev"
then
say "Subtree is already at commit $rev."
exit 0
fi
new=$(new_squash_commit "$old" "$sub" "$rev") || exit $?
debug "New squash commit: $new"
rev="$new"
fi
version=$(git version)
if test "$version" \< "git version 1.7"
then
if test -n "$message"
then
git merge -s subtree --message="$message" "$rev"
else
git merge -s subtree "$rev"
fi
else
if test -n "$message"
then
git merge -Xsubtree="$prefix" \
--message="$message" "$rev"
else
git merge -Xsubtree="$prefix" $rev
fi
fi
}
cmd_pull () {
if test $# -ne 2
then
die "You must provide <repository> <ref>"
fi
ensure_clean
ensure_valid_ref_format "$2"
git fetch "$@" || exit $?
revs=FETCH_HEAD
set -- $revs
cmd_merge "$@"
}
cmd_push () {
if test $# -ne 2
then
die "You must provide <repository> <ref>"
fi
ensure_valid_ref_format "$2"
if test -e "$dir"
then
repository=$1
refspec=$2
echo "git push using: " "$repository" "$refspec"
localrev=$(git subtree split --prefix="$prefix") || die
git push "$repository" "$localrev":"refs/heads/$refspec"
else
die "'$dir' must already exist. Try 'git subtree add'."
fi
}
"cmd_$command" "$@"
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