795e730e71
If any one of the parents is the same as the current one, then clearly the other parent branch isn't important, so throw it away entirely. Can't remember why I didn't do this before, but if I rediscover it, it definitely needs a unit test.
420 lines
8.4 KiB
Bash
Executable File
420 lines
8.4 KiB
Bash
Executable File
#!/bin/bash
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#
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# git-subtree.sh: split/join git repositories in subdirectories of this one
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#
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# Copyright (C) 2009 Avery Pennarun <apenwarr@gmail.com>
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#
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if [ $# -eq 0 ]; then
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set -- -h
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fi
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OPTS_SPEC="\
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git subtree add --prefix=<prefix> <commit>
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git subtree split [options...] --prefix=<prefix> <commit...>
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git subtree merge --prefix=<prefix> <commit>
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git subtree pull --prefix=<prefix> <repository> <refspec...>
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--
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h,help show the help
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q quiet
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prefix= the name of the subdir to split out
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options for 'split'
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annotate= add a prefix to commit message of new commits
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onto= try connecting new tree to an existing one
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rejoin merge the new branch back into HEAD
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ignore-joins ignore prior --rejoin commits
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"
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eval $(echo "$OPTS_SPEC" | git rev-parse --parseopt -- "$@" || echo exit $?)
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. git-sh-setup
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require_work_tree
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quiet=
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command=
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onto=
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rejoin=
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ignore_joins=
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annotate=
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debug()
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{
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if [ -z "$quiet" ]; then
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echo "$@" >&2
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fi
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}
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assert()
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{
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if "$@"; then
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:
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else
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die "assertion failed: " "$@"
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fi
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}
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#echo "Options: $*"
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while [ $# -gt 0 ]; do
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opt="$1"
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shift
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case "$opt" in
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-q) quiet=1 ;;
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--annotate) annotate="$1"; shift ;;
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--no-annotate) annotate= ;;
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--prefix) prefix="$1"; shift ;;
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--no-prefix) prefix= ;;
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--onto) onto="$1"; shift ;;
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--no-onto) onto= ;;
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--rejoin) rejoin=1 ;;
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--no-rejoin) rejoin= ;;
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--ignore-joins) ignore_joins=1 ;;
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--no-ignore-joins) ignore_joins= ;;
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--) break ;;
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esac
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done
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command="$1"
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shift
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case "$command" in
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add|merge|pull) default= ;;
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split) default="--default HEAD" ;;
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*) die "Unknown command '$command'" ;;
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esac
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if [ -z "$prefix" ]; then
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die "You must provide the --prefix option."
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fi
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dir="$prefix"
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if [ "$command" != "pull" ]; then
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revs=$(git rev-parse $default --revs-only "$@") || exit $?
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dirs="$(git rev-parse --no-revs --no-flags "$@")" || exit $?
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if [ -n "$dirs" ]; then
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die "Error: Use --prefix instead of bare filenames."
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fi
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fi
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debug "command: {$command}"
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debug "quiet: {$quiet}"
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debug "revs: {$revs}"
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debug "dir: {$dir}"
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debug "opts: {$*}"
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debug
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cache_setup()
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{
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cachedir="$GIT_DIR/subtree-cache/$$"
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rm -rf "$cachedir" || die "Can't delete old cachedir: $cachedir"
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mkdir -p "$cachedir" || die "Can't create new cachedir: $cachedir"
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debug "Using cachedir: $cachedir" >&2
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}
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cache_get()
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{
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for oldrev in $*; do
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if [ -r "$cachedir/$oldrev" ]; then
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read newrev <"$cachedir/$oldrev"
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echo $newrev
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fi
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done
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}
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cache_set()
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{
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oldrev="$1"
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newrev="$2"
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if [ "$oldrev" != "latest_old" \
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-a "$oldrev" != "latest_new" \
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-a -e "$cachedir/$oldrev" ]; then
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die "cache for $oldrev already exists!"
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fi
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echo "$newrev" >"$cachedir/$oldrev"
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}
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# if a commit doesn't have a parent, this might not work. But we only want
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# to remove the parent from the rev-list, and since it doesn't exist, it won't
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# be there anyway, so do nothing in that case.
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try_remove_previous()
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{
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if git rev-parse "$1^" >/dev/null 2>&1; then
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echo "^$1^"
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fi
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}
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find_existing_splits()
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{
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debug "Looking for prior splits..."
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dir="$1"
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revs="$2"
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git log --grep="^git-subtree-dir: $dir\$" \
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--pretty=format:'%s%n%n%b%nEND' $revs |
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while read a b junk; do
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case "$a" in
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git-subtree-mainline:) main="$b" ;;
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git-subtree-split:) sub="$b" ;;
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*)
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if [ -n "$main" -a -n "$sub" ]; then
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debug " Prior: $main -> $sub"
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cache_set $main $sub
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try_remove_previous "$main"
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try_remove_previous "$sub"
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main=
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sub=
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fi
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;;
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esac
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done
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}
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copy_commit()
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{
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# We're doing to set some environment vars here, so
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# do it in a subshell to get rid of them safely later
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debug copy_commit "{$1}" "{$2}" "{$3}"
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git log -1 --pretty=format:'%an%n%ae%n%ad%n%cn%n%ce%n%cd%n%s%n%n%b' "$1" |
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(
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read GIT_AUTHOR_NAME
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read GIT_AUTHOR_EMAIL
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read GIT_AUTHOR_DATE
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read GIT_COMMITTER_NAME
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read GIT_COMMITTER_EMAIL
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read GIT_COMMITTER_DATE
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export GIT_AUTHOR_NAME \
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GIT_AUTHOR_EMAIL \
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GIT_AUTHOR_DATE \
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GIT_COMMITTER_NAME \
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GIT_COMMITTER_EMAIL \
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GIT_COMMITTER_DATE
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(echo -n "$annotate"; cat ) |
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git commit-tree "$2" $3 # reads the rest of stdin
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) || die "Can't copy commit $1"
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}
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add_msg()
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{
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dir="$1"
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latest_old="$2"
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latest_new="$3"
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cat <<-EOF
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Add '$dir/' from commit '$latest_new'
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git-subtree-dir: $dir
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git-subtree-mainline: $latest_old
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git-subtree-split: $latest_new
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EOF
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}
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merge_msg()
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{
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dir="$1"
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latest_old="$2"
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latest_new="$3"
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cat <<-EOF
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Split '$dir/' into commit '$latest_new'
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git-subtree-dir: $dir
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git-subtree-mainline: $latest_old
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git-subtree-split: $latest_new
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EOF
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}
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toptree_for_commit()
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{
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commit="$1"
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git log -1 --pretty=format:'%T' "$commit" -- || exit $?
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}
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subtree_for_commit()
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{
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commit="$1"
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dir="$2"
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git ls-tree "$commit" -- "$dir" |
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while read mode type tree name; do
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assert [ "$name" = "$dir" ]
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echo $tree
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break
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done
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}
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tree_changed()
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{
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tree=$1
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shift
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if [ $# -ne 1 ]; then
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return 0 # weird parents, consider it changed
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else
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ptree=$(toptree_for_commit $1)
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if [ "$ptree" != "$tree" ]; then
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return 0 # changed
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else
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return 1 # not changed
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fi
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fi
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}
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copy_or_skip()
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{
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rev="$1"
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tree="$2"
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newparents="$3"
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assert [ -n "$tree" ]
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identical=
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nonidentical=
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p=
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gotparents=
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for parent in $newparents; do
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ptree=$(toptree_for_commit $parent) || exit $?
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[ -z "$ptree" ] && continue
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if [ "$ptree" = "$tree" ]; then
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# an identical parent could be used in place of this rev.
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identical="$parent"
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else
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nonidentical="$parent"
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fi
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# sometimes both old parents map to the same newparent;
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# eliminate duplicates
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is_new=1
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for gp in $gotparents; do
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if [ "$gp" = "$parent" ]; then
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is_new=
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break
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fi
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done
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if [ -n "$is_new" ]; then
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gotparents="$gotparents $parent"
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p="$p -p $parent"
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fi
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done
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if [ -n "$identical" ]; then
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echo $identical
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else
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copy_commit $rev $tree "$p" || exit $?
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fi
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}
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ensure_clean()
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{
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if ! git diff-index HEAD --exit-code --quiet; then
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die "Working tree has modifications. Cannot add."
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fi
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if ! git diff-index --cached HEAD --exit-code --quiet; then
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die "Index has modifications. Cannot add."
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fi
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}
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cmd_add()
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{
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if [ -e "$dir" ]; then
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die "'$dir' already exists. Cannot add."
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fi
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ensure_clean
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set -- $revs
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if [ $# -ne 1 ]; then
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die "You must provide exactly one revision. Got: '$revs'"
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fi
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rev="$1"
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debug "Adding $dir as '$rev'..."
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git read-tree --prefix="$dir" $rev || exit $?
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git checkout "$dir" || exit $?
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tree=$(git write-tree) || exit $?
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headrev=$(git rev-parse HEAD) || exit $?
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if [ -n "$headrev" -a "$headrev" != "$rev" ]; then
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headp="-p $headrev"
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else
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headp=
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fi
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commit=$(add_msg "$dir" "$headrev" "$rev" |
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git commit-tree $tree $headp -p "$rev") || exit $?
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git reset "$commit" || exit $?
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}
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cmd_split()
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{
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debug "Splitting $dir..."
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cache_setup || exit $?
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if [ -n "$onto" ]; then
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debug "Reading history for --onto=$onto..."
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git rev-list $onto |
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while read rev; do
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# the 'onto' history is already just the subdir, so
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# any parent we find there can be used verbatim
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debug " cache: $rev"
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cache_set $rev $rev
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done
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fi
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if [ -n "$ignore_joins" ]; then
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unrevs=
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else
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unrevs="$(find_existing_splits "$dir" "$revs")"
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fi
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# We can't restrict rev-list to only $dir here, because some of our
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# parents have the $dir contents the root, and those won't match.
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# (and rev-list --follow doesn't seem to solve this)
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git rev-list --reverse --parents $revs $unrevs |
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while read rev parents; do
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debug
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debug "Processing commit: $rev"
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exists=$(cache_get $rev)
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if [ -n "$exists" ]; then
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debug " prior: $exists"
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continue
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fi
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debug " parents: $parents"
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newparents=$(cache_get $parents)
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debug " newparents: $newparents"
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tree=$(subtree_for_commit $rev "$dir")
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debug " tree is: $tree"
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[ -z $tree ] && continue
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newrev=$(copy_or_skip "$rev" "$tree" "$newparents") || exit $?
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debug " newrev is: $newrev"
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cache_set $rev $newrev
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cache_set latest_new $newrev
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cache_set latest_old $rev
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done || exit $?
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latest_new=$(cache_get latest_new)
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if [ -z "$latest_new" ]; then
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die "No new revisions were found"
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fi
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if [ -n "$rejoin" ]; then
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debug "Merging split branch into HEAD..."
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latest_old=$(cache_get latest_old)
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git merge -s ours \
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-m "$(merge_msg $dir $latest_old $latest_new)" \
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$latest_new >&2
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fi
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echo $latest_new
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exit 0
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}
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cmd_merge()
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{
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ensure_clean
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set -- $revs
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if [ $# -ne 1 ]; then
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die "You must provide exactly one revision. Got: '$revs'"
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fi
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rev="$1"
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git merge -s subtree $rev
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}
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cmd_pull()
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{
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ensure_clean
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set -x
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git pull -s subtree "$@"
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}
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"cmd_$command" "$@"
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