https://github.com/git/git
Revision 8d2244ba74f5207b9f7f9f1b4efbcccacbbb2c7b authored by Andy Parkins on 02 July 2007, 12:56:58 UTC, committed by Junio C Hamano on 02 July 2007, 23:41:18 UTC
I ran git-prune on a repository and got this: $ git-prune error: Object 228f8065b930120e35fc0c154c237487ab02d64a is a blob, not a commit Segmentation fault (core dumped) This repository was a strange one in that it was being used to provide its own submodule. That is, the repository was cloned into a subdirectory, an independent branch checked out in that subdirectory, and then it was marked as a submodule. git-prune then failed in the above manner. The problem was that git-prune was not submodule aware in two areas. Linus said: > So what happens is that something traverses a tree object, looks at each > entry, sees that it's not a tree, and tries to look it up as a blob. But > subprojects are commits, not blobs, and then when you look at the object > more closely, you get the above kind of object type confusion. and included a patch to add an S_ISGITLINK() test to reachable.c's process_tree() function. That fixed the first git-prune error, and stopped it from trying to process the gitlink entries in trees as if they were pointers to other trees (and of course failing, because gitlinks _aren't_ trees). That part of this patch is his. The second area is add_cache_refs(). This is called before starting the reachability analysis, and was calling lookup_blob() on every object hash found in the index. However, it is no longer true that every hash in the index is a pointer to a blob, some of them are gitlinks, and are not backed by any object at all, they are commits in another repository. Normally this bug was not causing any problems, but in the case of the self-referencing repository described above, it meant that the gitlink hash was being marked as being of type OBJ_BLOB by add_cache_refs() call to lookup_blob(). Then later, because that hash was also pointed to by a ref, add_one_ref() would treat it as a commit; lookup_commit() would return a NULL because that object was already noted as being an OBJ_BLOB, not an OBJ_COMMIT; and parse_commit_buffer() would SEGFAULT on that NULL pointer. The fix made by this patch is to not blindly call lookup_blob() in reachable.c's add_cache_refs(), and instead skip any index entries that are S_ISGITLINK(). Signed-off-by: Andy Parkins <andyparkins@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
1 parent 5788744
Tip revision: 8d2244ba74f5207b9f7f9f1b4efbcccacbbb2c7b authored by Andy Parkins on 02 July 2007, 12:56:58 UTC
Make git-prune submodule aware (and fix a SEGFAULT in the process)
Make git-prune submodule aware (and fix a SEGFAULT in the process)
Tip revision: 8d2244b
git-merge.sh
#!/bin/sh
#
# Copyright (c) 2005 Junio C Hamano
#
USAGE='[-n] [--no-commit] [--squash] [-s <strategy>] [-m=<merge-message>] <commit>+'
SUBDIRECTORY_OK=Yes
. git-sh-setup
require_work_tree
cd_to_toplevel
test -z "$(git ls-files -u)" ||
die "You are in the middle of a conflicted merge."
LF='
'
all_strategies='recur recursive octopus resolve stupid ours subtree'
default_twohead_strategies='recursive'
default_octopus_strategies='octopus'
no_trivial_merge_strategies='ours subtree'
use_strategies=
index_merge=t
dropsave() {
rm -f -- "$GIT_DIR/MERGE_HEAD" "$GIT_DIR/MERGE_MSG" \
"$GIT_DIR/MERGE_SAVE" || exit 1
}
savestate() {
# Stash away any local modifications.
git-diff-index -z --name-only $head |
cpio -0 -o >"$GIT_DIR/MERGE_SAVE"
}
restorestate() {
if test -f "$GIT_DIR/MERGE_SAVE"
then
git reset --hard $head >/dev/null
cpio -iuv <"$GIT_DIR/MERGE_SAVE"
git-update-index --refresh >/dev/null
fi
}
finish_up_to_date () {
case "$squash" in
t)
echo "$1 (nothing to squash)" ;;
'')
echo "$1" ;;
esac
dropsave
}
squash_message () {
echo Squashed commit of the following:
echo
git-log --no-merges ^"$head" $remote
}
finish () {
if test '' = "$2"
then
rlogm="$GIT_REFLOG_ACTION"
else
echo "$2"
rlogm="$GIT_REFLOG_ACTION: $2"
fi
case "$squash" in
t)
echo "Squash commit -- not updating HEAD"
squash_message >"$GIT_DIR/SQUASH_MSG"
;;
'')
case "$merge_msg" in
'')
echo "No merge message -- not updating HEAD"
;;
*)
git-update-ref -m "$rlogm" HEAD "$1" "$head" || exit 1
;;
esac
;;
esac
case "$1" in
'')
;;
?*)
case "$no_summary" in
'')
git-diff-tree --stat --summary -M "$head" "$1"
;;
esac
;;
esac
}
merge_name () {
remote="$1"
rh=$(git-rev-parse --verify "$remote^0" 2>/dev/null) || return
bh=$(git-show-ref -s --verify "refs/heads/$remote" 2>/dev/null)
if test "$rh" = "$bh"
then
echo "$rh branch '$remote' of ."
elif truname=$(expr "$remote" : '\(.*\)~[1-9][0-9]*$') &&
git-show-ref -q --verify "refs/heads/$truname" 2>/dev/null
then
echo "$rh branch '$truname' (early part) of ."
elif test "$remote" = "FETCH_HEAD" -a -r "$GIT_DIR/FETCH_HEAD"
then
sed -e 's/ not-for-merge / /' -e 1q \
"$GIT_DIR/FETCH_HEAD"
else
echo "$rh commit '$remote'"
fi
}
case "$#" in 0) usage ;; esac
have_message=
while case "$#" in 0) break ;; esac
do
case "$1" in
-n|--n|--no|--no-|--no-s|--no-su|--no-sum|--no-summ|\
--no-summa|--no-summar|--no-summary)
no_summary=t ;;
--sq|--squ|--squa|--squas|--squash)
squash=t no_commit=t ;;
--no-c|--no-co|--no-com|--no-comm|--no-commi|--no-commit)
no_commit=t ;;
-s=*|--s=*|--st=*|--str=*|--stra=*|--strat=*|--strate=*|\
--strateg=*|--strategy=*|\
-s|--s|--st|--str|--stra|--strat|--strate|--strateg|--strategy)
case "$#,$1" in
*,*=*)
strategy=`expr "z$1" : 'z-[^=]*=\(.*\)'` ;;
1,*)
usage ;;
*)
strategy="$2"
shift ;;
esac
case " $all_strategies " in
*" $strategy "*)
use_strategies="$use_strategies$strategy " ;;
*)
die "available strategies are: $all_strategies" ;;
esac
;;
-m=*|--m=*|--me=*|--mes=*|--mess=*|--messa=*|--messag=*|--message=*)
merge_msg=`expr "z$1" : 'z-[^=]*=\(.*\)'`
have_message=t
;;
-m|--m|--me|--mes|--mess|--messa|--messag|--message)
shift
case "$#" in
1) usage ;;
esac
merge_msg="$1"
have_message=t
;;
-*) usage ;;
*) break ;;
esac
shift
done
# This could be traditional "merge <msg> HEAD <commit>..." and the
# way we can tell it is to see if the second token is HEAD, but some
# people might have misused the interface and used a committish that
# is the same as HEAD there instead. Traditional format never would
# have "-m" so it is an additional safety measure to check for it.
if test -z "$have_message" &&
second_token=$(git-rev-parse --verify "$2^0" 2>/dev/null) &&
head_commit=$(git-rev-parse --verify "HEAD" 2>/dev/null) &&
test "$second_token" = "$head_commit"
then
merge_msg="$1"
shift
head_arg="$1"
shift
elif ! git-rev-parse --verify HEAD >/dev/null 2>&1
then
# If the merged head is a valid one there is no reason to
# forbid "git merge" into a branch yet to be born. We do
# the same for "git pull".
if test 1 -ne $#
then
echo >&2 "Can merge only exactly one commit into empty head"
exit 1
fi
rh=$(git rev-parse --verify "$1^0") ||
die "$1 - not something we can merge"
git-update-ref -m "initial pull" HEAD "$rh" "" &&
git-read-tree --reset -u HEAD
exit
else
# We are invoked directly as the first-class UI.
head_arg=HEAD
# All the rest are the commits being merged; prepare
# the standard merge summary message to be appended to
# the given message. If remote is invalid we will die
# later in the common codepath so we discard the error
# in this loop.
merge_name=$(for remote
do
merge_name "$remote"
done | git-fmt-merge-msg
)
merge_msg="${merge_msg:+$merge_msg$LF$LF}$merge_name"
fi
head=$(git-rev-parse --verify "$head_arg"^0) || usage
# All the rest are remote heads
test "$#" = 0 && usage ;# we need at least one remote head.
set_reflog_action "merge $*"
remoteheads=
for remote
do
remotehead=$(git-rev-parse --verify "$remote"^0 2>/dev/null) ||
die "$remote - not something we can merge"
remoteheads="${remoteheads}$remotehead "
eval GITHEAD_$remotehead='"$remote"'
export GITHEAD_$remotehead
done
set x $remoteheads ; shift
case "$use_strategies" in
'')
case "$#" in
1)
var="`git-config --get pull.twohead`"
if test -n "$var"
then
use_strategies="$var"
else
use_strategies="$default_twohead_strategies"
fi ;;
*)
var="`git-config --get pull.octopus`"
if test -n "$var"
then
use_strategies="$var"
else
use_strategies="$default_octopus_strategies"
fi ;;
esac
;;
esac
for s in $use_strategies
do
for nt in $no_trivial_merge_strategies
do
case " $s " in
*" $nt "*)
index_merge=f
break
;;
esac
done
done
case "$#" in
1)
common=$(git-merge-base --all $head "$@")
;;
*)
common=$(git-show-branch --merge-base $head "$@")
;;
esac
echo "$head" >"$GIT_DIR/ORIG_HEAD"
case "$index_merge,$#,$common,$no_commit" in
f,*)
# We've been told not to try anything clever. Skip to real merge.
;;
?,*,'',*)
# No common ancestors found. We need a real merge.
;;
?,1,"$1",*)
# If head can reach all the merge then we are up to date.
# but first the most common case of merging one remote.
finish_up_to_date "Already up-to-date."
exit 0
;;
?,1,"$head",*)
# Again the most common case of merging one remote.
echo "Updating $(git-rev-parse --short $head)..$(git-rev-parse --short $1)"
git-update-index --refresh 2>/dev/null
msg="Fast forward"
if test -n "$have_message"
then
msg="$msg (no commit created; -m option ignored)"
fi
new_head=$(git-rev-parse --verify "$1^0") &&
git-read-tree -v -m -u --exclude-per-directory=.gitignore $head "$new_head" &&
finish "$new_head" "$msg" || exit
dropsave
exit 0
;;
?,1,?*"$LF"?*,*)
# We are not doing octopus and not fast forward. Need a
# real merge.
;;
?,1,*,)
# We are not doing octopus, not fast forward, and have only
# one common.
git-update-index --refresh 2>/dev/null
case " $use_strategies " in
*' recursive '*|*' recur '*)
: run merge later
;;
*)
# See if it is really trivial.
git var GIT_COMMITTER_IDENT >/dev/null || exit
echo "Trying really trivial in-index merge..."
if git-read-tree --trivial -m -u -v $common $head "$1" &&
result_tree=$(git-write-tree)
then
echo "Wonderful."
result_commit=$(
printf '%s\n' "$merge_msg" |
git-commit-tree $result_tree -p HEAD -p "$1"
) || exit
finish "$result_commit" "In-index merge"
dropsave
exit 0
fi
echo "Nope."
esac
;;
*)
# An octopus. If we can reach all the remote we are up to date.
up_to_date=t
for remote
do
common_one=$(git-merge-base --all $head $remote)
if test "$common_one" != "$remote"
then
up_to_date=f
break
fi
done
if test "$up_to_date" = t
then
finish_up_to_date "Already up-to-date. Yeeah!"
exit 0
fi
;;
esac
# We are going to make a new commit.
git var GIT_COMMITTER_IDENT >/dev/null || exit
# At this point, we need a real merge. No matter what strategy
# we use, it would operate on the index, possibly affecting the
# working tree, and when resolved cleanly, have the desired tree
# in the index -- this means that the index must be in sync with
# the $head commit. The strategies are responsible to ensure this.
case "$use_strategies" in
?*' '?*)
# Stash away the local changes so that we can try more than one.
savestate
single_strategy=no
;;
*)
rm -f "$GIT_DIR/MERGE_SAVE"
single_strategy=yes
;;
esac
result_tree= best_cnt=-1 best_strategy= wt_strategy=
merge_was_ok=
for strategy in $use_strategies
do
test "$wt_strategy" = '' || {
echo "Rewinding the tree to pristine..."
restorestate
}
case "$single_strategy" in
no)
echo "Trying merge strategy $strategy..."
;;
esac
# Remember which strategy left the state in the working tree
wt_strategy=$strategy
git-merge-$strategy $common -- "$head_arg" "$@"
exit=$?
if test "$no_commit" = t && test "$exit" = 0
then
merge_was_ok=t
exit=1 ;# pretend it left conflicts.
fi
test "$exit" = 0 || {
# The backend exits with 1 when conflicts are left to be resolved,
# with 2 when it does not handle the given merge at all.
if test "$exit" -eq 1
then
cnt=`{
git-diff-files --name-only
git-ls-files --unmerged
} | wc -l`
if test $best_cnt -le 0 -o $cnt -le $best_cnt
then
best_strategy=$strategy
best_cnt=$cnt
fi
fi
continue
}
# Automerge succeeded.
result_tree=$(git-write-tree) && break
done
# If we have a resulting tree, that means the strategy module
# auto resolved the merge cleanly.
if test '' != "$result_tree"
then
parents=$(git-show-branch --independent "$head" "$@" | sed -e 's/^/-p /')
result_commit=$(printf '%s\n' "$merge_msg" | git-commit-tree $result_tree $parents) || exit
finish "$result_commit" "Merge made by $wt_strategy."
dropsave
exit 0
fi
# Pick the result from the best strategy and have the user fix it up.
case "$best_strategy" in
'')
restorestate
case "$use_strategies" in
?*' '?*)
echo >&2 "No merge strategy handled the merge."
;;
*)
echo >&2 "Merge with strategy $use_strategies failed."
;;
esac
exit 2
;;
"$wt_strategy")
# We already have its result in the working tree.
;;
*)
echo "Rewinding the tree to pristine..."
restorestate
echo "Using the $best_strategy to prepare resolving by hand."
git-merge-$best_strategy $common -- "$head_arg" "$@"
;;
esac
if test "$squash" = t
then
finish
else
for remote
do
echo $remote
done >"$GIT_DIR/MERGE_HEAD"
printf '%s\n' "$merge_msg" >"$GIT_DIR/MERGE_MSG"
fi
if test "$merge_was_ok" = t
then
echo >&2 \
"Automatic merge went well; stopped before committing as requested"
exit 0
else
{
echo '
Conflicts:
'
git ls-files --unmerged |
sed -e 's/^[^ ]* / /' |
uniq
} >>"$GIT_DIR/MERGE_MSG"
if test -d "$GIT_DIR/rr-cache"
then
git-rerere
fi
die "Automatic merge failed; fix conflicts and then commit the result."
fi
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