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git/t/t5500-fetch-pack.sh
Junio C Hamano 3d5c418ff5 git-clone: aggressively optimize local clone behaviour.
This changes the behaviour of cloning from a repository on the
local machine, by defaulting to "-l" (use hardlinks to share
files under .git/objects) and making "-l" a no-op.  A new
option, --no-hardlinks, is also added to cause file-level copy
of files under .git/objects while still avoiding the normal
"pack to pipe, then receive and index pack" network transfer
overhead.  The old behaviour of local cloning without -l nor -s
is availble by specifying the source repository with the newly
introduced file:///path/to/repo.git/ syntax (i.e. "same as
network" cloning).

 * With --no-hardlinks (i.e. have all .git/objects/ copied via
   cpio) would not catch the source repository corruption, and
   also risks corrupted recipient repository if an
   alpha-particle hits memory cell while indexing and resolving
   deltas.  As long as the recipient is created uncorrupted, you
   have a good back-up.

 * same-as-network is expensive, but it would catch the breakage
   of the source repository.  It still risks corrupted recipient
   repository due to hardware failure.  As long as the recipient
   is created uncorrupted, you have a good back-up.

 * The new default on the same filesystem, as long as the source
   repository is healthy, it is very likely that the recipient
   would be, too.  Also it is very cheap.  You do not get any
   back-up benefit, though.

None of the method is resilient against the source repository
corruption, so let's discount that from the comparison.  Then
the difference with and without --no-hardlinks matters primarily
if you value the back-up benefit or not.  If you want to use the
cloned repository as a back-up, then it is cheaper to do a clone
with --no-hardlinks and two git-fsck (source before clone,
recipient after clone) than same-as-network clone, especially as
you are likely to do a git-fsck on the recipient if you are so
paranoid anyway.

Which leads me to believe that being able to use file:/// is
probably a good idea, if only for testability, but probably of
little practical value.  We default to hardlinked clone for
everyday use, and paranoids can use --no-hardlinks as a way to
make a back-up.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2007-08-01 23:42:36 -07:00

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#!/bin/sh
#
# Copyright (c) 2005 Johannes Schindelin
#
test_description='Testing multi_ack pack fetching
'
. ./test-lib.sh
# Test fetch-pack/upload-pack pair.
# Some convenience functions
add () {
name=$1
text="$@"
branch=`echo $name | sed -e 's/^\(.\).*$/\1/'`
parents=""
shift
while test $1; do
parents="$parents -p $1"
shift
done
echo "$text" > test.txt
git update-index --add test.txt
tree=$(git write-tree)
# make sure timestamps are in correct order
sec=$(($sec+1))
commit=$(echo "$text" | GIT_AUTHOR_DATE=$sec \
git commit-tree $tree $parents 2>>log2.txt)
export $name=$commit
echo $commit > .git/refs/heads/$branch
eval ${branch}TIP=$commit
}
count_objects () {
ls .git/objects/??/* 2>>log2.txt | wc -l | tr -d " "
}
test_expect_object_count () {
message=$1
count=$2
output="$(count_objects)"
test_expect_success \
"new object count $message" \
"test $count = $output"
}
pull_to_client () {
number=$1
heads=$2
count=$3
no_strict_count_check=$4
cd client
test_expect_success "$number pull" \
"git-fetch-pack -k -v .. $heads"
case "$heads" in *A*) echo $ATIP > .git/refs/heads/A;; esac
case "$heads" in *B*) echo $BTIP > .git/refs/heads/B;; esac
git symbolic-ref HEAD refs/heads/`echo $heads | sed -e 's/^\(.\).*$/\1/'`
test_expect_success "fsck" 'git fsck --full > fsck.txt 2>&1'
test_expect_success 'check downloaded results' \
'mv .git/objects/pack/pack-* . &&
p=`ls -1 pack-*.pack` &&
git unpack-objects <$p &&
git fsck --full'
test_expect_success "new object count after $number pull" \
'idx=`echo pack-*.idx` &&
pack_count=`git show-index <$idx | wc -l` &&
test $pack_count = $count'
test -z "$pack_count" && pack_count=0
if [ -z "$no_strict_count_check" ]; then
test_expect_success "minimal count" "test $count = $pack_count"
else
test $count != $pack_count && \
echo "WARNING: $pack_count objects transmitted, only $count of which were needed"
fi
rm -f pack-*
cd ..
}
# Here begins the actual testing
# A1 - ... - A20 - A21
# \
# B1 - B2 - .. - B70
# client pulls A20, B1. Then tracks only B. Then pulls A.
(
mkdir client &&
cd client &&
git init 2>> log2.txt &&
git config transfer.unpacklimit 0
)
add A1
prev=1; cur=2; while [ $cur -le 10 ]; do
add A$cur $(eval echo \$A$prev)
prev=$cur
cur=$(($cur+1))
done
add B1 $A1
echo $ATIP > .git/refs/heads/A
echo $BTIP > .git/refs/heads/B
git symbolic-ref HEAD refs/heads/B
pull_to_client 1st "B A" $((11*3))
add A11 $A10
prev=1; cur=2; while [ $cur -le 65 ]; do
add B$cur $(eval echo \$B$prev)
prev=$cur
cur=$(($cur+1))
done
pull_to_client 2nd "B" $((64*3))
pull_to_client 3rd "A" $((1*3)) # old fails
test_expect_success "clone shallow" "git-clone --depth 2 file://`pwd`/. shallow"
(cd shallow; git count-objects -v) > count.shallow
test_expect_success "clone shallow object count" \
"test \"in-pack: 18\" = \"$(grep in-pack count.shallow)\""
count_output () {
sed -e '/^in-pack:/d' -e '/^packs:/d' -e '/: 0$/d' "$1"
}
test_expect_success "clone shallow object count (part 2)" '
test -z "$(count_output count.shallow)"
'
test_expect_success "fsck in shallow repo" \
"(cd shallow; git fsck --full)"
#test_done; exit
add B66 $B65
add B67 $B66
test_expect_success "pull in shallow repo" \
"(cd shallow; git pull .. B)"
(cd shallow; git count-objects -v) > count.shallow
test_expect_success "clone shallow object count" \
"test \"count: 6\" = \"$(grep count count.shallow)\""
add B68 $B67
add B69 $B68
test_expect_success "deepening pull in shallow repo" \
"(cd shallow; git pull --depth 4 .. B)"
(cd shallow; git count-objects -v) > count.shallow
test_expect_success "clone shallow object count" \
"test \"count: 12\" = \"$(grep count count.shallow)\""
test_expect_success "deepening fetch in shallow repo" \
"(cd shallow; git fetch --depth 4 .. A:A)"
(cd shallow; git count-objects -v) > count.shallow
test_expect_success "clone shallow object count" \
"test \"count: 18\" = \"$(grep count count.shallow)\""
test_expect_failure "pull in shallow repo with missing merge base" \
"(cd shallow; git pull --depth 4 .. A)"
test_done