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nixpkgs/pkgs/build-support/fetchgit/nix-prefetch-git
Jan Tojnar 28faf5bc86
nix-prefetch-git: Fix output mangling
`git repack` and `git gc` sometimes print “Nothing new to pack.”
to stdout, which breaks redirecting output to JSON file.

Let’s move the stdout of all git calls where it is not used to stderr
so that we still receive the info but it does not pollute our output.
2020-02-14 22:15:36 +01:00

447 lines
12 KiB
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Executable file

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