#!/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 } 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 $? if test -n "$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 "$@") for miss in $missed do if ! test -r "$cachedir/notree/$miss" then debug " incorrect order: $miss" fi done } set_notree () { echo "1" > "$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: $dir/*\$" \ --pretty=format:'START %H%n%s%n%n%b%nEND%n' HEAD | while read a b junk do debug "$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= git log --grep="^git-subtree-dir: $dir/*\$" \ --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 --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 --pretty=tformat:'%h %s' "$oldsub..$newsub" git log --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="$1" git log -1 --pretty=format:'%T' "$commit" -- || 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= 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. identical="$parent" else nonidentical="$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 $parent" fi done copycommit= if test -n "$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 "'$1' does not look like a ref" } cmd_add () { if test -e "$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 () { revs=$(git rev-parse $default --revs-only "$@") || exit $? set -- $revs rev="$1" 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" "$rev" done fi if test -n "$ignore_joins" then unrevs= else unrevs="$(find_existing_splits "$dir" "$revs")" fi # 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 "$grl" | wc -l) revcount=0 createcount=0 eval "$grl" | while read rev parents do revcount=$(($revcount + 1)) progress "$revcount/$revmax ($createcount)" debug "Processing commit: $rev" exists=$(cache_get "$rev") if test -n "$exists" then debug " prior: $exists" continue fi createcount=$(($createcount + 1)) debug " parents: $parents" newparents=$(cache_get $parents) debug " newparents: $newparents" tree=$(subtree_for_commit "$rev" "$dir") debug " tree is: $tree" check_parents $parents # ugly. is there no better way to tell if this is a subtree # vs. a mainline commit? Does it matter? if test -z "$tree" then set_notree "$rev" if test -n "$newparents" then cache_set "$rev" "$rev" fi continue 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" 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 () { revs=$(git rev-parse $default --revs-only "$@") || exit $? ensure_clean set -- $revs if test $# -ne 1 then die "You must provide exactly one revision. Got: '$revs'" fi rev="$1" if test -n "$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" "$@"