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[PATCH] Multi-head fetch.
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Traditionally, fetch takes these forms:

    $ git fetch <remote>
    $ git fetch <remote> <head>
    $ git fetch <remote> tag <tag>

This patch updates it to take

    $ git fetch <remote> <refspec>...

where:

    - A <refspec> of form "<src>:<dst>" is to fetch the objects
      needed for the remote ref that matches <src>, and if <dst>
      is not empty, store it as a local <dst>.

    - "tag" followed by <next> is just an old way of saying
      "refs/tags/<next>:refs/tags/<next>"; this mimics the
      current behaviour of the third form above and means "fetch
      that tag and store it under the same name".

    - A single token <refspec> without colon is a shorthand for
      "<refspec>:"  That is, "fetch that ref but do not store
      anywhere".

    - when there is no <refspec> specified

      - if <remote> is the name of a file under $GIT_DIR/remotes/
	(i.e. a new-style shorthand), then it is the same as giving
	the <refspec>s listed on Pull: line in that file.

      - if <remote> is the name of a file under $GIT_DIR/branches/
	(i.e. an old-style shorthand, without trailing path), then it
	is the same as giving a single <refspec>
	"<remote-name>:refs/heads/<remote>" on the command line, where
	<remote-name> is the remote branch name (defaults to HEAD, but
	can be overridden by .git/branches/<remote> file having the
	URL fragment notation).  That is, "fetch that branch head and
	store it in refs/heads/<remote>".

      - otherwise, it is the same as giving a single <refspec>
        that is "HEAD:".

The SHA1 object names of fetched refs are stored in FETCH_HEAD,
one name per line, with a comment to describe where it came from.
This is later used by "git resolve" and "git octopus".

Signed-off-by: Junio C Hamano <junkio@cox.net>
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Junio C Hamano committed Aug 24, 2005
1 parent ac4b0cf commit 853a369
Showing 1 changed file with 147 additions and 42 deletions.
189 changes: 147 additions & 42 deletions git-fetch-script
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Original file line number Diff line number Diff line change
@@ -1,54 +1,159 @@
#!/bin/sh
#
. git-sh-setup-script || die "Not a git archive"
. git-parse-remote "$@"
merge_repo="$_remote_repo"
merge_head="$_remote_head"
merge_store="$_remote_store"

TMP_HEAD="$GIT_DIR/TMP_HEAD"

case "$merge_repo" in
http://* | https://*)
if [ -n "$GIT_SSL_NO_VERIFY" ]; then
curl_extra_args="-k"
fi
_x40='[0-9a-f][0-9a-f][0-9a-f][0-9a-f][0-9a-f]' &&
_x40="$_x40$_x40$_x40$_x40$_x40$_x40$_x40$_x40" &&
head=$(curl -nsf $curl_extra_args "$merge_repo/$merge_head") &&
expr "$head" : "$_x40\$" >/dev/null || {
echo >&2 "Failed to fetch $merge_head from $merge_repo"
exit 1
}
echo Fetching "$merge_head" using http
git-http-pull -v -a "$head" "$merge_repo/" || exit
;;
rsync://*)
rsync -L "$merge_repo/$merge_head" "$TMP_HEAD" || exit 1
head=$(git-rev-parse TMP_HEAD)
rm -f "$TMP_HEAD"
rsync -avz --ignore-existing "$merge_repo/objects/" "$GIT_OBJECT_DIRECTORY/"
;;
. git-parse-remote-script
_x40='[0-9a-f][0-9a-f][0-9a-f][0-9a-f][0-9a-f]'
_x40="$_x40$_x40$_x40$_x40$_x40$_x40$_x40$_x40"

append=
case "$#" in
0)
die "Where do you want to fetch from?" ;;
*)
head=$(git-fetch-pack "$merge_repo" "$merge_head")
if h=`expr "$head" : '\([^ ][^ ]*\) '`
case "$1" in
-a|--a|--ap|--app|--appe|--appen|--append)
append=t
shift ;;
esac
esac
remote_nick="$1"
remote=$(get_remote_url "$@")
refs=
rref=
rsync_slurped_objects=

if test "" = "$append"
then
: >$GIT_DIR/FETCH_HEAD
fi

append_fetch_head () {
head_="$1"
remote_="$2"
remote_name_="$3"
remote_nick_="$4"
local_name_="$5"

# 2.6.11-tree tag would not be happy to be fed to resolve.
if git-cat-file commit "$head_" >/dev/null 2>&1
then
head_=$(git-rev-parse --verify "$head_^0") || exit
note_="$head_ $remote_name_ from $remote_nick_"
echo "$note_" >>$GIT_DIR/FETCH_HEAD
echo >&2 "* committish: $note_"
else
echo >&2 "* non-commit: $note_"
fi
if test "$local_name_" != ""
then
# We are storing the head locally. Make sure that it is
# a fast forward (aka "reverse push").
fast_forward_local "$local_name_" "$head_" "$remote_" "$remote_name_"
fi
}

fast_forward_local () {
case "$1" in
refs/tags/*)
# Tags need not be pointing at commits so there
# is no way to guarantee "fast-forward" anyway.
echo "$2" >"$GIT_DIR/$1" ;;
refs/heads/*)
# NEEDSWORK: use the same cmpxchg protocol here.
echo "$2" >"$GIT_DIR/$1.lock"
if test -f "$GIT_DIR/$1"
then
head=$h
local=$(git-rev-parse --verify "$1^0") &&
mb=$(git-merge-base "$local" "$2") &&
case "$2,$mb" in
$local,*)
echo >&2 "* $1: same as $4"
echo >&2 " from $3"
;;
*,$local)
echo >&2 "* $1: fast forward to $4"
echo >&2 " from $3"
;;
*)
false
;;
esac || {
mv "$GIT_DIR/$1.lock" "$GIT_DIR/$1.remote"
echo >&2 "* $1: does not fast forward to $4"
echo >&2 " from $3; leaving it in '$1.remote'"
}
else
echo >&2 "* $1: storing $4"
echo >&2 " from $3."
fi
test -f "$GIT_DIR/$1.lock" &&
mv "$GIT_DIR/$1.lock" "$GIT_DIR/$1"
;;
esac || exit 1
esac
}

for ref in $(get_remote_refs_for_fetch "$@")
do
refs="$refs $ref"

git-rev-parse --verify "$head" > /dev/null || exit 1
# These are relative path from $GIT_DIR, typically starting at refs/
# but may be HEAD
remote_name=$(expr "$ref" : '\([^:]*\):')
local_name=$(expr "$ref" : '[^:]*:\(.*\)')

case "$merge_store" in
'')
rref="$rref $remote_name"

# There are transports that can fetch only one head at a time...
case "$remote" in
http://* | https://*)
if [ -n "$GIT_SSL_NO_VERIFY" ]; then
curl_extra_args="-k"
fi
head=$(curl -nsf $curl_extra_args "$remote/$remote_name") &&
expr "$head" : "$_x40\$" >/dev/null ||
die "Failed to fetch $remote_name from $remote"
echo Fetching "$remote_name from $remote" using http
git-http-pull -v -a "$head" "$remote/" || exit
;;
*)
echo "$head" > "$GIT_DIR/$merge_store"
esac &&
rsync://*)
TMP_HEAD="$GIT_DIR/TMP_HEAD"
rsync -L "$remote/$remote_name" "$TMP_HEAD" || exit 1
head=$(git-rev-parse TMP_HEAD)
rm -f "$TMP_HEAD"
test "$rsync_slurped_objects" || {
rsync -avz --ignore-existing "$remote/objects/" \
"$GIT_OBJECT_DIRECTORY/" || exit
rsync_slurped_objects=t
}
;;
*)
# We will do git native transport with just one call later.
continue ;;
esac

append_fetch_head "$head" "$remote" "$remote_name" "$remote_nick" "$local_name"

# FETCH_HEAD is fed to git-resolve-script which will eventually be
# passed to git-commit-tree as one of the parents. Make sure we do
# not give a tag object ID.
done

case "$remote" in
http://* | https://* | rsync://* )
;; # we are already done.
*)
git-fetch-pack "$remote" $rref |
while read sha1 remote_name
do
found=
for ref in $refs
do
case "$ref" in
$remote_name:*)
found="$ref"
break ;;
esac
done

git-rev-parse "$head^0" >"$GIT_DIR/FETCH_HEAD"
local_name=$(expr "$found" : '[^:]*:\(.*\)')
append_fetch_head "$sha1" "$remote" "$remote_name" "$remote_nick" "$local_name"
done
;;
esac

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