11df41199b
It's hugely inefficient as we can't use shallow cloning (--depth=1). This has been tested and adapted for quite a few hosts fetchgit is used on in Nixpkgs. For those where fetching the hash directly doesn't work (most notably git.savannah.gnu.org), we simply fall back to the old method.
468 lines
12 KiB
Bash
Executable file
468 lines
12 KiB
Bash
Executable file
#! /usr/bin/env bash
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set -e -o pipefail
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url=
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rev=
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expHash=
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hashType=$NIX_HASH_ALGO
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deepClone=$NIX_PREFETCH_GIT_DEEP_CLONE
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leaveDotGit=$NIX_PREFETCH_GIT_LEAVE_DOT_GIT
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fetchSubmodules=
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fetchLFS=
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builder=
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branchName=$NIX_PREFETCH_GIT_BRANCH_NAME
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# ENV params
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out=${out:-}
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http_proxy=${http_proxy:-}
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# populated by clone_user_rev()
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fullRev=
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humanReadableRev=
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commitDate=
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commitDateStrict8601=
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if test -n "$deepClone"; then
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deepClone=true
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else
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deepClone=
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fi
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if test "$leaveDotGit" != 1; then
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leaveDotGit=
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else
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leaveDotGit=true
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fi
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usage(){
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echo >&2 "syntax: nix-prefetch-git [options] [URL [REVISION [EXPECTED-HASH]]]
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Options:
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--out path Path where the output would be stored.
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--url url Any url understood by 'git clone'.
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--rev ref Any sha1 or references (such as refs/heads/master)
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--hash h Expected hash.
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--branch-name Branch name to check out into
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--deepClone Clone the entire repository.
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--no-deepClone Make a shallow clone of just the required ref.
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--leave-dotGit Keep the .git directories.
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--fetch-lfs Fetch git Large File Storage (LFS) files.
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--fetch-submodules Fetch submodules.
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--builder Clone as fetchgit does, but url, rev, and out option are mandatory.
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--quiet Only print the final json summary.
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"
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exit 1
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}
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# some git commands print to stdout, which would contaminate our JSON output
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clean_git(){
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git "$@" >&2
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}
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argi=0
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argfun=""
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for arg; do
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if test -z "$argfun"; then
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case $arg in
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--out) argfun=set_out;;
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--url) argfun=set_url;;
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--rev) argfun=set_rev;;
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--hash) argfun=set_hashType;;
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--branch-name) argfun=set_branchName;;
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--deepClone) deepClone=true;;
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--quiet) QUIET=true;;
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--no-deepClone) deepClone=;;
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--leave-dotGit) leaveDotGit=true;;
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--fetch-lfs) fetchLFS=true;;
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--fetch-submodules) fetchSubmodules=true;;
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--builder) builder=true;;
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-h|--help) usage; exit;;
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*)
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: $((++argi))
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case $argi in
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1) url=$arg;;
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2) rev=$arg;;
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3) expHash=$arg;;
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*) exit 1;;
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esac
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;;
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esac
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else
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case $argfun in
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set_*)
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var=${argfun#set_}
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eval $var=$arg
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;;
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esac
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argfun=""
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fi
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done
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if test -z "$url"; then
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usage
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fi
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init_remote(){
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local url=$1
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clean_git init --initial-branch=master
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clean_git remote add origin "$url"
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( [ -n "$http_proxy" ] && clean_git config http.proxy "$http_proxy" ) || true
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}
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# Return the reference of an hash if it exists on the remote repository.
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ref_from_hash(){
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local hash=$1
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git ls-remote origin | sed -n "\,$hash\t, { s,\(.*\)\t\(.*\),\2,; p; q}"
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}
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# Return the hash of a reference if it exists on the remote repository.
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hash_from_ref(){
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local ref=$1
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git ls-remote origin | sed -n "\,\t$ref, { s,\(.*\)\t\(.*\),\1,; p; q}"
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}
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# Returns a name based on the url and reference
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#
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# This function needs to be in sync with nix's fetchgit implementation
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# of urlToName() to re-use the same nix store paths.
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url_to_name(){
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local url=$1
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local ref=$2
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local base
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base=$(basename "$url" .git | cut -d: -f2)
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if [[ $ref =~ ^[a-z0-9]+$ ]]; then
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echo "$base-${ref:0:7}"
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else
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echo "$base"
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fi
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}
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# Fetch and checkout the right sha1
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checkout_hash(){
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local hash="$1"
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local ref="$2"
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if test -z "$hash"; then
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hash=$(hash_from_ref "$ref")
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fi
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clean_git fetch ${builder:+--progress} --depth=1 origin "$hash" || \
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clean_git fetch -t ${builder:+--progress} origin || return 1
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local object_type=$(git cat-file -t "$hash")
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if [[ "$object_type" == "commit" ]]; then
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clean_git checkout -b "$branchName" "$hash" || return 1
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elif [[ "$object_type" == "tree" ]]; then
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clean_git config user.email "nix-prefetch-git@localhost"
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clean_git config user.name "nix-prefetch-git"
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local commit_id=$(git commit-tree "$hash" -m "Commit created from tree hash $hash")
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clean_git checkout -b "$branchName" "$commit_id" || return 1
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else
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echo "Unrecognized git object type: $object_type"
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return 1
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fi
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}
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# Fetch only a branch/tag and checkout it.
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checkout_ref(){
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local hash="$1"
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local ref="$2"
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if [[ -n "$deepClone" ]]; then
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# The caller explicitly asked for a deep clone. Deep clones
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# allow "git describe" and similar tools to work. See
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# https://marc.info/?l=nix-dev&m=139641582514772
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# for a discussion.
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return 1
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fi
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if test -z "$ref"; then
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ref=$(ref_from_hash "$hash")
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fi
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if test -n "$ref"; then
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# --depth option is ignored on http repository.
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clean_git fetch ${builder:+--progress} --depth 1 origin +"$ref" || return 1
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clean_git checkout -b "$branchName" FETCH_HEAD || return 1
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else
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return 1
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fi
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}
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# Update submodules
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init_submodules(){
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# Add urls into .git/config file
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clean_git submodule init
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# list submodule directories and their hashes
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git submodule status |
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while read -r l; do
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local hash
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local dir
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local name
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local url
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# checkout each submodule
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hash=$(echo "$l" | awk '{print $1}' | tr -d '-')
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dir=$(echo "$l" | sed -n 's/^.[0-9a-f]\+ \(.*[^)]*\)\( (.*)\)\?$/\1/p')
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name=$(
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git config -f .gitmodules --get-regexp submodule\..*\.path |
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sed -n "s,^\(.*\)\.path $dir\$,\\1,p")
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url=$(git config --get "${name}.url")
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clone "$dir" "$url" "$hash" ""
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done
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}
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clone(){
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local top=$PWD
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local dir="$1"
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local url="$2"
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local hash="$3"
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local ref="$4"
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cd "$dir"
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# Initialize the repository.
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init_remote "$url"
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# Download data from the repository.
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checkout_ref "$hash" "$ref" ||
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checkout_hash "$hash" "$ref" || (
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echo 1>&2 "Unable to checkout $hash$ref from $url."
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exit 1
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)
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# Checkout linked sources.
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if test -n "$fetchSubmodules"; then
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init_submodules
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fi
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if [ -z "$builder" ] && [ -f .topdeps ]; then
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if tg help &>/dev/null; then
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echo "populating TopGit branches..."
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tg remote --populate origin
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else
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echo "WARNING: would populate TopGit branches but TopGit is not available" >&2
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echo "WARNING: install TopGit to fix the problem" >&2
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fi
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fi
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cd "$top"
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}
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# Remove all remote branches, remove tags not reachable from HEAD, do a full
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# repack and then garbage collect unreferenced objects.
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make_deterministic_repo(){
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local repo="$1"
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# run in sub-shell to not touch current working directory
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(
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cd "$repo"
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# Remove files that contain timestamps or otherwise have non-deterministic
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# properties.
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rm -rf .git/logs/ .git/hooks/ .git/index .git/FETCH_HEAD .git/ORIG_HEAD \
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.git/refs/remotes/origin/HEAD .git/config
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# Remove all remote branches.
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git branch -r | while read -r branch; do
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clean_git branch -rD "$branch"
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done
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# Remove tags not reachable from HEAD. If we're exactly on a tag, don't
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# delete it.
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maybe_tag=$(git tag --points-at HEAD)
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git tag --contains HEAD | while read -r tag; do
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if [ "$tag" != "$maybe_tag" ]; then
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clean_git tag -d "$tag"
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fi
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done
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# Do a full repack. Must run single-threaded, or else we lose determinism.
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clean_git config pack.threads 1
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clean_git repack -A -d -f
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rm -f .git/config
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# Garbage collect unreferenced objects.
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# Note: --keep-largest-pack prevents non-deterministic ordering of packs
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# listed in .git/objects/info/packs by only using a single pack
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clean_git gc --prune=all --keep-largest-pack
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)
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}
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clone_user_rev() {
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local dir="$1"
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local url="$2"
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local rev="${3:-HEAD}"
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if [ -n "$fetchLFS" ]; then
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HOME=$TMPDIR
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git lfs install
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fi
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# Perform the checkout.
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case "$rev" in
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HEAD|refs/*)
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clone "$dir" "$url" "" "$rev" 1>&2;;
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*)
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if test -z "$(echo "$rev" | tr -d 0123456789abcdef)"; then
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clone "$dir" "$url" "$rev" "" 1>&2
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else
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# if revision is not hexadecimal it might be a tag
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clone "$dir" "$url" "" "refs/tags/$rev" 1>&2
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fi;;
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esac
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pushd "$dir" >/dev/null
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fullRev=$( (git rev-parse "$rev" 2>/dev/null || git rev-parse "refs/heads/$branchName") | tail -n1)
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humanReadableRev=$(git describe "$fullRev" 2> /dev/null || git describe --tags "$fullRev" 2> /dev/null || echo -- none --)
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commitDate=$(git show -1 --no-patch --pretty=%ci "$fullRev")
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commitDateStrict8601=$(git show -1 --no-patch --pretty=%cI "$fullRev")
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popd >/dev/null
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# Allow doing additional processing before .git removal
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eval "$NIX_PREFETCH_GIT_CHECKOUT_HOOK"
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if test -z "$leaveDotGit"; then
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echo "removing \`.git'..." >&2
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find "$dir" -name .git -print0 | xargs -0 rm -rf
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else
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find "$dir" -name .git | while read -r gitdir; do
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make_deterministic_repo "$(readlink -f "$gitdir/..")"
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done
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fi
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}
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exit_handlers=()
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run_exit_handlers() {
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exit_status=$?
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for handler in "${exit_handlers[@]}"; do
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eval "$handler $exit_status"
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done
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}
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trap run_exit_handlers EXIT
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quiet_exit_handler() {
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exec 2>&3 3>&-
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if [ $1 -ne 0 ]; then
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cat "$errfile" >&2
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fi
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rm -f "$errfile"
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}
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quiet_mode() {
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errfile="$(mktemp "${TMPDIR:-/tmp}/git-checkout-err-XXXXXXXX")"
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exit_handlers+=(quiet_exit_handler)
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exec 3>&2 2>"$errfile"
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}
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json_escape() {
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local s="$1"
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s="${s//\\/\\\\}" # \
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s="${s//\"/\\\"}" # "
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s="${s//^H/\\\b}" # \b (backspace)
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s="${s//^L/\\\f}" # \f (form feed)
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s="${s//
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/\\\n}" # \n (newline)
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s="${s//^M/\\\r}" # \r (carriage return)
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s="${s// /\\t}" # \t (tab)
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echo "$s"
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}
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print_results() {
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hash="$1"
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if ! test -n "$QUIET"; then
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echo "" >&2
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echo "git revision is $fullRev" >&2
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if test -n "$finalPath"; then
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echo "path is $finalPath" >&2
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fi
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echo "git human-readable version is $humanReadableRev" >&2
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echo "Commit date is $commitDate" >&2
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if test -n "$hash"; then
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echo "hash is $hash" >&2
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fi
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fi
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if test -n "$hash"; then
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cat <<EOF
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{
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"url": "$(json_escape "$url")",
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"rev": "$(json_escape "$fullRev")",
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"date": "$(json_escape "$commitDateStrict8601")",
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"path": "$(json_escape "$finalPath")",
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"$(json_escape "$hashType")": "$(json_escape "$hash")",
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"fetchSubmodules": $([[ -n "$fetchSubmodules" ]] && echo true || echo false),
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"deepClone": $([[ -n "$deepClone" ]] && echo true || echo false),
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"leaveDotGit": $([[ -n "$leaveDotGit" ]] && echo true || echo false)
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}
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EOF
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fi
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}
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remove_tmpPath() {
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rm -rf "$tmpPath"
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}
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if test -n "$QUIET"; then
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quiet_mode
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fi
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if test -z "$branchName"; then
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branchName=fetchgit
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fi
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if test -n "$builder"; then
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test -n "$out" -a -n "$url" -a -n "$rev" || usage
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mkdir -p "$out"
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clone_user_rev "$out" "$url" "$rev"
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else
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if test -z "$hashType"; then
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hashType=sha256
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fi
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# If the hash was given, a file with that hash may already be in the
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# store.
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if test -n "$expHash"; then
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finalPath=$(nix-store --print-fixed-path --recursive "$hashType" "$expHash" "$(url_to_name "$url" "$rev")")
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if ! nix-store --check-validity "$finalPath" 2> /dev/null; then
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finalPath=
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fi
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hash=$expHash
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fi
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# If we don't know the hash or a path with that hash doesn't exist,
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# download the file and add it to the store.
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if test -z "$finalPath"; then
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tmpPath="$(mktemp -d "${TMPDIR:-/tmp}/git-checkout-tmp-XXXXXXXX")"
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exit_handlers+=(remove_tmpPath)
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tmpFile="$tmpPath/$(url_to_name "$url" "$rev")"
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mkdir -p "$tmpFile"
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# Perform the checkout.
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clone_user_rev "$tmpFile" "$url" "$rev"
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# Compute the hash.
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hash=$(nix-hash --type $hashType --base32 "$tmpFile")
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# Add the downloaded file to the Nix store.
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finalPath=$(nix-store --add-fixed --recursive "$hashType" "$tmpFile")
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if test -n "$expHash" -a "$expHash" != "$hash"; then
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echo "hash mismatch for URL \`$url'. Got \`$hash'; expected \`$expHash'." >&2
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exit 1
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fi
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fi
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print_results "$hash"
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if test -n "$PRINT_PATH"; then
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echo "$finalPath"
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fi
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fi
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