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https://github.com/git/git
synced 2024-08-27 19:49:21 +00:00
![Charles Bailey](/assets/img/avatar_default.png)
When multiple parents of a merge commit get mapped to the same commit, filter-branch used to pass all instances of the parent commit to the parent and commit filters and to "git commit-tree" or "git_commit_non_empty_tree". This can often happen when extracting a small project from a large repository; merges can join history with no commits on any branch which affect the paths being retained. Once the intermediate commits have been filtered out, all the immediate parents of the merge commit can end up being mapped to the same commit - either the original merge-base or an ancestor of it. "git commit-tree" would display an error but write the commit with the normalized parents in any case. "git_commit_non_empty_tree" would fail to notice that the commit being made was in fact a non-merge commit and would retain it even if a further pass with "--prune-empty" would discard the commit as empty. Ensure that duplicate parents are pruned before the parent filter to make "--prune-empty" idempotent, removing all empty non-merge commits in a singe pass. Signed-off-by: Charles Bailey <cbailey32@bloomberg.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
503 lines
12 KiB
Bash
Executable file
503 lines
12 KiB
Bash
Executable file
#!/bin/sh
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#
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# Rewrite revision history
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# Copyright (c) Petr Baudis, 2006
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# Minimal changes to "port" it to core-git (c) Johannes Schindelin, 2007
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#
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# Lets you rewrite the revision history of the current branch, creating
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# a new branch. You can specify a number of filters to modify the commits,
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# files and trees.
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# The following functions will also be available in the commit filter:
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functions=$(cat << \EOF
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warn () {
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echo "$*" >&2
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}
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map()
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{
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# if it was not rewritten, take the original
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if test -r "$workdir/../map/$1"
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then
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cat "$workdir/../map/$1"
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else
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echo "$1"
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fi
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}
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# if you run 'skip_commit "$@"' in a commit filter, it will print
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# the (mapped) parents, effectively skipping the commit.
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skip_commit()
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{
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shift;
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while [ -n "$1" ];
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do
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shift;
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map "$1";
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shift;
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done;
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}
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# if you run 'git_commit_non_empty_tree "$@"' in a commit filter,
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# it will skip commits that leave the tree untouched, commit the other.
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git_commit_non_empty_tree()
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{
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if test $# = 3 && test "$1" = $(git rev-parse "$3^{tree}"); then
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map "$3"
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else
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git commit-tree "$@"
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fi
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}
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# override die(): this version puts in an extra line break, so that
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# the progress is still visible
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die()
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{
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echo >&2
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echo "$*" >&2
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exit 1
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}
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EOF
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)
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eval "$functions"
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finish_ident() {
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# Ensure non-empty id name.
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echo "case \"\$GIT_$1_NAME\" in \"\") GIT_$1_NAME=\"\${GIT_$1_EMAIL%%@*}\" && export GIT_$1_NAME;; esac"
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# And make sure everything is exported.
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echo "export GIT_$1_NAME"
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echo "export GIT_$1_EMAIL"
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echo "export GIT_$1_DATE"
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}
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set_ident () {
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parse_ident_from_commit author AUTHOR committer COMMITTER
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finish_ident AUTHOR
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finish_ident COMMITTER
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}
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USAGE="[--env-filter <command>] [--tree-filter <command>]
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[--index-filter <command>] [--parent-filter <command>]
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[--msg-filter <command>] [--commit-filter <command>]
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[--tag-name-filter <command>] [--subdirectory-filter <directory>]
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[--original <namespace>] [-d <directory>] [-f | --force]
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[<rev-list options>...]"
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OPTIONS_SPEC=
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. git-sh-setup
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if [ "$(is_bare_repository)" = false ]; then
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require_clean_work_tree 'rewrite branches'
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fi
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tempdir=.git-rewrite
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filter_env=
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filter_tree=
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filter_index=
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filter_parent=
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filter_msg=cat
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filter_commit=
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filter_tag_name=
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filter_subdir=
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orig_namespace=refs/original/
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force=
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prune_empty=
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remap_to_ancestor=
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while :
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do
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case "$1" in
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--)
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shift
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break
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;;
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--force|-f)
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shift
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force=t
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continue
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;;
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--remap-to-ancestor)
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# deprecated ($remap_to_ancestor is set now automatically)
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shift
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remap_to_ancestor=t
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continue
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;;
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--prune-empty)
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shift
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prune_empty=t
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continue
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;;
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-*)
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;;
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*)
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break;
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esac
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# all switches take one argument
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ARG="$1"
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case "$#" in 1) usage ;; esac
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shift
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OPTARG="$1"
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shift
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case "$ARG" in
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-d)
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tempdir="$OPTARG"
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;;
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--env-filter)
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filter_env="$OPTARG"
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;;
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--tree-filter)
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filter_tree="$OPTARG"
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;;
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--index-filter)
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filter_index="$OPTARG"
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;;
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--parent-filter)
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filter_parent="$OPTARG"
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;;
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--msg-filter)
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filter_msg="$OPTARG"
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;;
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--commit-filter)
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filter_commit="$functions; $OPTARG"
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;;
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--tag-name-filter)
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filter_tag_name="$OPTARG"
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;;
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--subdirectory-filter)
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filter_subdir="$OPTARG"
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remap_to_ancestor=t
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;;
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--original)
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orig_namespace=$(expr "$OPTARG/" : '\(.*[^/]\)/*$')/
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;;
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*)
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usage
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;;
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esac
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done
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case "$prune_empty,$filter_commit" in
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,)
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filter_commit='git commit-tree "$@"';;
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t,)
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filter_commit="$functions;"' git_commit_non_empty_tree "$@"';;
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,*)
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;;
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*)
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die "Cannot set --prune-empty and --commit-filter at the same time"
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esac
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case "$force" in
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t)
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rm -rf "$tempdir"
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;;
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'')
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test -d "$tempdir" &&
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die "$tempdir already exists, please remove it"
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esac
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orig_dir=$(pwd)
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mkdir -p "$tempdir/t" &&
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tempdir="$(cd "$tempdir"; pwd)" &&
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cd "$tempdir/t" &&
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workdir="$(pwd)" ||
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die ""
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# Remove tempdir on exit
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trap 'cd "$orig_dir"; rm -rf "$tempdir"' 0
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ORIG_GIT_DIR="$GIT_DIR"
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ORIG_GIT_WORK_TREE="$GIT_WORK_TREE"
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ORIG_GIT_INDEX_FILE="$GIT_INDEX_FILE"
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GIT_WORK_TREE=.
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export GIT_DIR GIT_WORK_TREE
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# Make sure refs/original is empty
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git for-each-ref > "$tempdir"/backup-refs || exit
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while read sha1 type name
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do
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case "$force,$name" in
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,$orig_namespace*)
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die "Cannot create a new backup.
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A previous backup already exists in $orig_namespace
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Force overwriting the backup with -f"
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;;
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t,$orig_namespace*)
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git update-ref -d "$name" $sha1
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;;
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esac
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done < "$tempdir"/backup-refs
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# The refs should be updated if their heads were rewritten
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git rev-parse --no-flags --revs-only --symbolic-full-name \
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--default HEAD "$@" > "$tempdir"/raw-heads || exit
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sed -e '/^^/d' "$tempdir"/raw-heads >"$tempdir"/heads
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test -s "$tempdir"/heads ||
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die "Which ref do you want to rewrite?"
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GIT_INDEX_FILE="$(pwd)/../index"
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export GIT_INDEX_FILE
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# map old->new commit ids for rewriting parents
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mkdir ../map || die "Could not create map/ directory"
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# we need "--" only if there are no path arguments in $@
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nonrevs=$(git rev-parse --no-revs "$@") || exit
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if test -z "$nonrevs"
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then
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dashdash=--
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else
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dashdash=
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remap_to_ancestor=t
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fi
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git rev-parse --revs-only "$@" >../parse
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case "$filter_subdir" in
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"")
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eval set -- "$(git rev-parse --sq --no-revs "$@")"
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;;
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*)
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eval set -- "$(git rev-parse --sq --no-revs "$@" $dashdash \
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"$filter_subdir")"
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;;
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esac
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git rev-list --reverse --topo-order --default HEAD \
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--parents --simplify-merges --stdin "$@" <../parse >../revs ||
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die "Could not get the commits"
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commits=$(wc -l <../revs | tr -d " ")
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test $commits -eq 0 && die "Found nothing to rewrite"
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# Rewrite the commits
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git_filter_branch__commit_count=0
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while read commit parents; do
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git_filter_branch__commit_count=$(($git_filter_branch__commit_count+1))
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printf "\rRewrite $commit ($git_filter_branch__commit_count/$commits)"
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case "$filter_subdir" in
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"")
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GIT_ALLOW_NULL_SHA1=1 git read-tree -i -m $commit
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;;
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*)
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# The commit may not have the subdirectory at all
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err=$(GIT_ALLOW_NULL_SHA1=1 \
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git read-tree -i -m $commit:"$filter_subdir" 2>&1) || {
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if ! git rev-parse -q --verify $commit:"$filter_subdir"
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then
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rm -f "$GIT_INDEX_FILE"
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else
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echo >&2 "$err"
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false
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fi
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}
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esac || die "Could not initialize the index"
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GIT_COMMIT=$commit
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export GIT_COMMIT
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git cat-file commit "$commit" >../commit ||
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die "Cannot read commit $commit"
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eval "$(set_ident <../commit)" ||
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die "setting author/committer failed for commit $commit"
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eval "$filter_env" < /dev/null ||
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die "env filter failed: $filter_env"
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if [ "$filter_tree" ]; then
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git checkout-index -f -u -a ||
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die "Could not checkout the index"
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# files that $commit removed are now still in the working tree;
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# remove them, else they would be added again
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git clean -d -q -f -x
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eval "$filter_tree" < /dev/null ||
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die "tree filter failed: $filter_tree"
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(
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git diff-index -r --name-only --ignore-submodules $commit &&
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git ls-files --others
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) > "$tempdir"/tree-state || exit
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git update-index --add --replace --remove --stdin \
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< "$tempdir"/tree-state || exit
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fi
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eval "$filter_index" < /dev/null ||
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die "index filter failed: $filter_index"
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parentstr=
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for parent in $parents; do
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for reparent in $(map "$parent"); do
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case "$parentstr " in
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*" -p $reparent "*)
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;;
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*)
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parentstr="$parentstr -p $reparent"
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;;
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esac
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done
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done
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if [ "$filter_parent" ]; then
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parentstr="$(echo "$parentstr" | eval "$filter_parent")" ||
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die "parent filter failed: $filter_parent"
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fi
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sed -e '1,/^$/d' <../commit | \
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eval "$filter_msg" > ../message ||
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die "msg filter failed: $filter_msg"
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workdir=$workdir @SHELL_PATH@ -c "$filter_commit" "git commit-tree" \
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$(git write-tree) $parentstr < ../message > ../map/$commit ||
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die "could not write rewritten commit"
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done <../revs
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# If we are filtering for paths, as in the case of a subdirectory
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# filter, it is possible that a specified head is not in the set of
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# rewritten commits, because it was pruned by the revision walker.
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# Ancestor remapping fixes this by mapping these heads to the unique
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# nearest ancestor that survived the pruning.
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if test "$remap_to_ancestor" = t
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then
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while read ref
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do
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sha1=$(git rev-parse "$ref"^0)
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test -f "$workdir"/../map/$sha1 && continue
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ancestor=$(git rev-list --simplify-merges -1 "$ref" "$@")
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test "$ancestor" && echo $(map $ancestor) >> "$workdir"/../map/$sha1
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done < "$tempdir"/heads
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fi
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# Finally update the refs
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_x40='[0-9a-f][0-9a-f][0-9a-f][0-9a-f][0-9a-f]'
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_x40="$_x40$_x40$_x40$_x40$_x40$_x40$_x40$_x40"
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echo
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while read ref
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do
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# avoid rewriting a ref twice
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test -f "$orig_namespace$ref" && continue
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sha1=$(git rev-parse "$ref"^0)
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rewritten=$(map $sha1)
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test $sha1 = "$rewritten" &&
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warn "WARNING: Ref '$ref' is unchanged" &&
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continue
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case "$rewritten" in
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'')
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echo "Ref '$ref' was deleted"
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git update-ref -m "filter-branch: delete" -d "$ref" $sha1 ||
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die "Could not delete $ref"
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;;
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$_x40)
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echo "Ref '$ref' was rewritten"
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if ! git update-ref -m "filter-branch: rewrite" \
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"$ref" $rewritten $sha1 2>/dev/null; then
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if test $(git cat-file -t "$ref") = tag; then
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if test -z "$filter_tag_name"; then
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warn "WARNING: You said to rewrite tagged commits, but not the corresponding tag."
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warn "WARNING: Perhaps use '--tag-name-filter cat' to rewrite the tag."
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fi
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else
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die "Could not rewrite $ref"
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fi
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fi
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;;
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*)
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# NEEDSWORK: possibly add -Werror, making this an error
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warn "WARNING: '$ref' was rewritten into multiple commits:"
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warn "$rewritten"
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warn "WARNING: Ref '$ref' points to the first one now."
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rewritten=$(echo "$rewritten" | head -n 1)
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git update-ref -m "filter-branch: rewrite to first" \
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"$ref" $rewritten $sha1 ||
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die "Could not rewrite $ref"
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;;
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esac
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git update-ref -m "filter-branch: backup" "$orig_namespace$ref" $sha1 ||
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exit
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done < "$tempdir"/heads
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# TODO: This should possibly go, with the semantics that all positive given
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# refs are updated, and their original heads stored in refs/original/
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# Filter tags
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if [ "$filter_tag_name" ]; then
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git for-each-ref --format='%(objectname) %(objecttype) %(refname)' refs/tags |
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while read sha1 type ref; do
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ref="${ref#refs/tags/}"
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# XXX: Rewrite tagged trees as well?
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if [ "$type" != "commit" -a "$type" != "tag" ]; then
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continue;
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fi
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if [ "$type" = "tag" ]; then
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# Dereference to a commit
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sha1t="$sha1"
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sha1="$(git rev-parse -q "$sha1"^{commit})" || continue
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fi
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[ -f "../map/$sha1" ] || continue
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new_sha1="$(cat "../map/$sha1")"
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GIT_COMMIT="$sha1"
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export GIT_COMMIT
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new_ref="$(echo "$ref" | eval "$filter_tag_name")" ||
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die "tag name filter failed: $filter_tag_name"
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echo "$ref -> $new_ref ($sha1 -> $new_sha1)"
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if [ "$type" = "tag" ]; then
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new_sha1=$( ( printf 'object %s\ntype commit\ntag %s\n' \
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"$new_sha1" "$new_ref"
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git cat-file tag "$ref" |
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sed -n \
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-e '1,/^$/{
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/^object /d
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/^type /d
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/^tag /d
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}' \
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-e '/^-----BEGIN PGP SIGNATURE-----/q' \
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-e 'p' ) |
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git mktag) ||
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die "Could not create new tag object for $ref"
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if git cat-file tag "$ref" | \
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sane_grep '^-----BEGIN PGP SIGNATURE-----' >/dev/null 2>&1
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then
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warn "gpg signature stripped from tag object $sha1t"
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fi
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fi
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git update-ref "refs/tags/$new_ref" "$new_sha1" ||
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die "Could not write tag $new_ref"
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done
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fi
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cd "$orig_dir"
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rm -rf "$tempdir"
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trap - 0
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unset GIT_DIR GIT_WORK_TREE GIT_INDEX_FILE
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test -z "$ORIG_GIT_DIR" || {
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GIT_DIR="$ORIG_GIT_DIR" && export GIT_DIR
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}
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test -z "$ORIG_GIT_WORK_TREE" || {
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GIT_WORK_TREE="$ORIG_GIT_WORK_TREE" &&
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export GIT_WORK_TREE
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}
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test -z "$ORIG_GIT_INDEX_FILE" || {
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GIT_INDEX_FILE="$ORIG_GIT_INDEX_FILE" &&
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export GIT_INDEX_FILE
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}
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if [ "$(is_bare_repository)" = false ]; then
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git read-tree -u -m HEAD || exit
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fi
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exit 0
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