convert: fix git convert using servers branches
The conversion from git to hg was reading the remote branch list directly from
the origin server. If the origin's branch had moved forward since the last git
fetch, it would return a git hash which didn't exist locally, and therefore the
branch was not converted.
This changes it to rely on the local repo's refs/remotes list of branches
instead, so it's completely cut off from the server.
#require git
$ echo "[core]" >> $HOME/.gitconfig
$ echo "autocrlf = false" >> $HOME/.gitconfig
$ echo "[core]" >> $HOME/.gitconfig
$ echo "autocrlf = false" >> $HOME/.gitconfig
$ echo "[extensions]" >> $HGRCPATH
$ echo "convert=" >> $HGRCPATH
$ GIT_AUTHOR_NAME='test'; export GIT_AUTHOR_NAME
$ GIT_AUTHOR_EMAIL='test@example.org'; export GIT_AUTHOR_EMAIL
$ GIT_AUTHOR_DATE="2007-01-01 00:00:00 +0000"; export GIT_AUTHOR_DATE
$ GIT_COMMITTER_NAME="$GIT_AUTHOR_NAME"; export GIT_COMMITTER_NAME
$ GIT_COMMITTER_EMAIL="$GIT_AUTHOR_EMAIL"; export GIT_COMMITTER_EMAIL
$ GIT_COMMITTER_DATE="$GIT_AUTHOR_DATE"; export GIT_COMMITTER_DATE
$ INVALIDID1=afd12345af
$ INVALIDID2=28173x36ddd1e67bf7098d541130558ef5534a86
$ VALIDID1=39b3d83f9a69a9ba4ebb111461071a0af0027357
$ VALIDID2=8dd6476bd09d9c7776355dc454dafe38efaec5da
$ count=10
$ commit()
> {
> GIT_AUTHOR_DATE="2007-01-01 00:00:$count +0000"
> GIT_COMMITTER_DATE="$GIT_AUTHOR_DATE"
> git commit "$@" >/dev/null 2>/dev/null || echo "git commit error"
> count=`expr $count + 1`
> }
$ mkdir git-repo
$ cd git-repo
$ git init-db >/dev/null 2>/dev/null
$ echo a > a
$ mkdir d
$ echo b > d/b
$ git add a d
$ commit -a -m t1
Remove the directory, then try to replace it with a file (issue754)
$ git rm -f d/b
rm 'd/b'
$ commit -m t2
$ echo d > d
$ git add d
$ commit -m t3
$ echo b >> a
$ commit -a -m t4.1
$ git checkout -b other HEAD~ >/dev/null 2>/dev/null
$ echo c > a
$ echo a >> a
$ commit -a -m t4.2
$ git checkout master >/dev/null 2>/dev/null
$ git pull --no-commit . other > /dev/null 2>/dev/null
$ commit -m 'Merge branch other'
$ cd ..
$ hg convert --config extensions.progress= --config progress.assume-tty=1 \
> --config progress.delay=0 --config progress.changedelay=0 \
> --config progress.refresh=0 --config progress.width=60 \
> --datesort git-repo
\r (no-eol) (esc)
scanning [======> ] 1/6\r (no-eol) (esc)
scanning [=============> ] 2/6\r (no-eol) (esc)
scanning [=====================> ] 3/6\r (no-eol) (esc)
scanning [============================> ] 4/6\r (no-eol) (esc)
scanning [===================================> ] 5/6\r (no-eol) (esc)
scanning [===========================================>] 6/6\r (no-eol) (esc)
\r (no-eol) (esc)
\r (no-eol) (esc)
converting [ ] 0/6\r (no-eol) (esc)
getting files [==================> ] 1/2\r (no-eol) (esc)
getting files [======================================>] 2/2\r (no-eol) (esc)
\r (no-eol) (esc)
\r (no-eol) (esc)
converting [======> ] 1/6\r (no-eol) (esc)
getting files [======================================>] 1/1\r (no-eol) (esc)
\r (no-eol) (esc)
\r (no-eol) (esc)
converting [=============> ] 2/6\r (no-eol) (esc)
getting files [======================================>] 1/1\r (no-eol) (esc)
\r (no-eol) (esc)
\r (no-eol) (esc)
converting [====================> ] 3/6\r (no-eol) (esc)
getting files [======================================>] 1/1\r (no-eol) (esc)
\r (no-eol) (esc)
\r (no-eol) (esc)
converting [===========================> ] 4/6\r (no-eol) (esc)
getting files [======================================>] 1/1\r (no-eol) (esc)
\r (no-eol) (esc)
\r (no-eol) (esc)
converting [==================================> ] 5/6\r (no-eol) (esc)
getting files [======================================>] 1/1\r (no-eol) (esc)
\r (no-eol) (esc)
assuming destination git-repo-hg
initializing destination git-repo-hg repository
scanning source...
sorting...
converting...
5 t1
4 t2
3 t3
2 t4.1
1 t4.2
0 Merge branch other
updating bookmarks
$ hg up -q -R git-repo-hg
$ hg -R git-repo-hg tip -v
changeset: 5:c78094926be2
bookmark: master
tag: tip
parent: 3:f5f5cb45432b
parent: 4:4e174f80c67c
user: test <test@example.org>
date: Mon Jan 01 00:00:15 2007 +0000
files: a
description:
Merge branch other
$ count=10
$ mkdir git-repo2
$ cd git-repo2
$ git init-db >/dev/null 2>/dev/null
$ echo foo > foo
$ git add foo
$ commit -a -m 'add foo'
$ echo >> foo
$ commit -a -m 'change foo'
$ git checkout -b Bar HEAD~ >/dev/null 2>/dev/null
$ echo quux >> quux
$ git add quux
$ commit -a -m 'add quux'
$ echo bar > bar
$ git add bar
$ commit -a -m 'add bar'
$ git checkout -b Baz HEAD~ >/dev/null 2>/dev/null
$ echo baz > baz
$ git add baz
$ commit -a -m 'add baz'
$ git checkout master >/dev/null 2>/dev/null
$ git pull --no-commit . Bar Baz > /dev/null 2>/dev/null
$ commit -m 'Octopus merge'
$ echo bar >> bar
$ commit -a -m 'change bar'
$ git checkout -b Foo HEAD~ >/dev/null 2>/dev/null
$ echo >> foo
$ commit -a -m 'change foo'
$ git checkout master >/dev/null 2>/dev/null
$ git pull --no-commit -s ours . Foo > /dev/null 2>/dev/null
$ commit -m 'Discard change to foo'
$ cd ..
$ glog()
> {
> hg log -G --template '{rev} "{desc|firstline}" files: {files}\n' "$@"
> }
$ splitrepo()
> {
> msg="$1"
> files="$2"
> opts=$3
> echo "% $files: $msg"
> prefix=`echo "$files" | sed -e 's/ /-/g'`
> fmap="$prefix.fmap"
> repo="$prefix.repo"
> for i in $files; do
> echo "include $i" >> "$fmap"
> done
> hg -q convert $opts --filemap "$fmap" --datesort git-repo2 "$repo"
> hg up -q -R "$repo"
> glog -R "$repo"
> hg -R "$repo" manifest --debug
> }
full conversion
$ hg convert --datesort git-repo2 fullrepo \
> --config extensions.progress= --config progress.assume-tty=1 \
> --config progress.delay=0 --config progress.changedelay=0 \
> --config progress.refresh=0 --config progress.width=60
\r (no-eol) (esc)
scanning [===> ] 1/9\r (no-eol) (esc)
scanning [========> ] 2/9\r (no-eol) (esc)
scanning [=============> ] 3/9\r (no-eol) (esc)
scanning [==================> ] 4/9\r (no-eol) (esc)
scanning [=======================> ] 5/9\r (no-eol) (esc)
scanning [============================> ] 6/9\r (no-eol) (esc)
scanning [=================================> ] 7/9\r (no-eol) (esc)
scanning [======================================> ] 8/9\r (no-eol) (esc)
scanning [===========================================>] 9/9\r (no-eol) (esc)
\r (no-eol) (esc)
\r (no-eol) (esc)
converting [ ] 0/9\r (no-eol) (esc)
getting files [======================================>] 1/1\r (no-eol) (esc)
\r (no-eol) (esc)
\r (no-eol) (esc)
converting [===> ] 1/9\r (no-eol) (esc)
getting files [======================================>] 1/1\r (no-eol) (esc)
\r (no-eol) (esc)
\r (no-eol) (esc)
converting [========> ] 2/9\r (no-eol) (esc)
getting files [======================================>] 1/1\r (no-eol) (esc)
\r (no-eol) (esc)
\r (no-eol) (esc)
converting [=============> ] 3/9\r (no-eol) (esc)
getting files [======================================>] 1/1\r (no-eol) (esc)
\r (no-eol) (esc)
\r (no-eol) (esc)
converting [=================> ] 4/9\r (no-eol) (esc)
getting files [======================================>] 1/1\r (no-eol) (esc)
\r (no-eol) (esc)
\r (no-eol) (esc)
converting [======================> ] 5/9\r (no-eol) (esc)
getting files [===> ] 1/8\r (no-eol) (esc)
getting files [========> ] 2/8\r (no-eol) (esc)
getting files [=============> ] 3/8\r (no-eol) (esc)
getting files [==================> ] 4/8\r (no-eol) (esc)
getting files [=======================> ] 5/8\r (no-eol) (esc)
getting files [============================> ] 6/8\r (no-eol) (esc)
getting files [=================================> ] 7/8\r (no-eol) (esc)
getting files [======================================>] 8/8\r (no-eol) (esc)
\r (no-eol) (esc)
\r (no-eol) (esc)
converting [===========================> ] 6/9\r (no-eol) (esc)
getting files [======================================>] 1/1\r (no-eol) (esc)
\r (no-eol) (esc)
\r (no-eol) (esc)
converting [===============================> ] 7/9\r (no-eol) (esc)
getting files [======================================>] 1/1\r (no-eol) (esc)
\r (no-eol) (esc)
\r (no-eol) (esc)
converting [====================================> ] 8/9\r (no-eol) (esc)
getting files [==================> ] 1/2\r (no-eol) (esc)
getting files [======================================>] 2/2\r (no-eol) (esc)
\r (no-eol) (esc)
initializing destination fullrepo repository
scanning source...
sorting...
converting...
8 add foo
7 change foo
6 add quux
5 add bar
4 add baz
3 Octopus merge
2 change bar
1 change foo
0 Discard change to foo
updating bookmarks
$ hg up -q -R fullrepo
$ glog -R fullrepo
@ 9 "Discard change to foo" files: foo
|\
| o 8 "change foo" files: foo
| |
o | 7 "change bar" files: bar
|/
o 6 "(octopus merge fixup)" files:
|\
| o 5 "Octopus merge" files: baz
| |\
o | | 4 "add baz" files: baz
| | |
+---o 3 "add bar" files: bar
| |
o | 2 "add quux" files: quux
| |
| o 1 "change foo" files: foo
|/
o 0 "add foo" files: foo
$ hg -R fullrepo manifest --debug
245a3b8bc653999c2b22cdabd517ccb47aecafdf 644 bar
354ae8da6e890359ef49ade27b68bbc361f3ca88 644 baz
9277c9cc8dd4576fc01a17939b4351e5ada93466 644 foo
88dfeab657e8cf2cef3dec67b914f49791ae76b1 644 quux
$ splitrepo 'octopus merge' 'foo bar baz'
% foo bar baz: octopus merge
@ 8 "Discard change to foo" files: foo
|\
| o 7 "change foo" files: foo
| |
o | 6 "change bar" files: bar
|/
o 5 "(octopus merge fixup)" files:
|\
| o 4 "Octopus merge" files: baz
| |\
o | | 3 "add baz" files: baz
| | |
+---o 2 "add bar" files: bar
| |
| o 1 "change foo" files: foo
|/
o 0 "add foo" files: foo
245a3b8bc653999c2b22cdabd517ccb47aecafdf 644 bar
354ae8da6e890359ef49ade27b68bbc361f3ca88 644 baz
9277c9cc8dd4576fc01a17939b4351e5ada93466 644 foo
$ splitrepo 'only some parents of an octopus merge; "discard" a head' 'foo baz quux'
% foo baz quux: only some parents of an octopus merge; "discard" a head
@ 6 "Discard change to foo" files: foo
|
o 5 "change foo" files: foo
|
o 4 "Octopus merge" files:
|\
| o 3 "add baz" files: baz
| |
| o 2 "add quux" files: quux
| |
o | 1 "change foo" files: foo
|/
o 0 "add foo" files: foo
354ae8da6e890359ef49ade27b68bbc361f3ca88 644 baz
9277c9cc8dd4576fc01a17939b4351e5ada93466 644 foo
88dfeab657e8cf2cef3dec67b914f49791ae76b1 644 quux
test importing git renames and copies
$ cd git-repo2
$ git mv foo foo-renamed
since bar is not touched in this commit, this copy will not be detected
$ cp bar bar-copied
$ cp baz baz-copied
$ cp baz baz-copied2
$ echo baz2 >> baz
$ git add bar-copied baz-copied baz-copied2
$ commit -a -m 'rename and copy'
$ cd ..
input validation
$ hg convert --config convert.git.similarity=foo --datesort git-repo2 fullrepo
abort: convert.git.similarity is not an integer ('foo')
[255]
$ hg convert --config convert.git.similarity=-1 --datesort git-repo2 fullrepo
abort: similarity must be between 0 and 100
[255]
$ hg convert --config convert.git.similarity=101 --datesort git-repo2 fullrepo
abort: similarity must be between 0 and 100
[255]
$ hg -q convert --config convert.git.similarity=100 --datesort git-repo2 fullrepo
$ hg -R fullrepo status -C --change master
M baz
A bar-copied
A baz-copied
baz
A baz-copied2
baz
A foo-renamed
foo
R foo
$ cd git-repo2
$ echo bar2 >> bar
$ commit -a -m 'change bar'
$ cp bar bar-copied2
$ git add bar-copied2
$ commit -a -m 'copy with no changes'
$ cd ..
$ hg -q convert --config convert.git.similarity=100 \
> --config convert.git.findcopiesharder=1 --datesort git-repo2 fullrepo
$ hg -R fullrepo status -C --change master
A bar-copied2
bar
test binary conversion (issue1359)
$ count=19
$ mkdir git-repo3
$ cd git-repo3
$ git init-db >/dev/null 2>/dev/null
$ $PYTHON -c 'file("b", "wb").write("".join([chr(i) for i in range(256)])*16)'
$ git add b
$ commit -a -m addbinary
$ cd ..
convert binary file
$ hg convert git-repo3 git-repo3-hg
initializing destination git-repo3-hg repository
scanning source...
sorting...
converting...
0 addbinary
updating bookmarks
$ cd git-repo3-hg
$ hg up -C
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ $PYTHON -c 'print len(file("b", "rb").read())'
4096
$ cd ..
test author vs committer
$ mkdir git-repo4
$ cd git-repo4
$ git init-db >/dev/null 2>/dev/null
$ echo >> foo
$ git add foo
$ commit -a -m addfoo
$ echo >> foo
$ GIT_AUTHOR_NAME="nottest"
$ commit -a -m addfoo2
$ cd ..
convert author committer
$ hg convert git-repo4 git-repo4-hg
initializing destination git-repo4-hg repository
scanning source...
sorting...
converting...
1 addfoo
0 addfoo2
updating bookmarks
$ hg -R git-repo4-hg log -v
changeset: 1:d63e967f93da
bookmark: master
tag: tip
user: nottest <test@example.org>
date: Mon Jan 01 00:00:21 2007 +0000
files: foo
description:
addfoo2
committer: test <test@example.org>
changeset: 0:0735477b0224
user: test <test@example.org>
date: Mon Jan 01 00:00:20 2007 +0000
files: foo
description:
addfoo
--sourceorder should fail
$ hg convert --sourcesort git-repo4 git-repo4-sourcesort-hg
initializing destination git-repo4-sourcesort-hg repository
abort: --sourcesort is not supported by this data source
[255]
test converting certain branches
$ mkdir git-testrevs
$ cd git-testrevs
$ git init
Initialized empty Git repository in $TESTTMP/git-testrevs/.git/
$ echo a >> a ; git add a > /dev/null; git commit -m 'first' > /dev/null
$ echo a >> a ; git add a > /dev/null; git commit -m 'master commit' > /dev/null
$ git checkout -b goodbranch 'HEAD^'
Switched to a new branch 'goodbranch'
$ echo a >> b ; git add b > /dev/null; git commit -m 'good branch commit' > /dev/null
$ git checkout -b badbranch 'HEAD^'
Switched to a new branch 'badbranch'
$ echo a >> c ; git add c > /dev/null; git commit -m 'bad branch commit' > /dev/null
$ cd ..
$ hg convert git-testrevs hg-testrevs --rev master --rev goodbranch
initializing destination hg-testrevs repository
scanning source...
sorting...
converting...
2 first
1 good branch commit
0 master commit
updating bookmarks
$ cd hg-testrevs
$ hg log -G -T '{rev} {bookmarks}'
o 2 master
|
| o 1 goodbranch
|/
o 0
$ cd ..
test sub modules
$ mkdir git-repo5
$ cd git-repo5
$ git init-db >/dev/null 2>/dev/null
$ echo 'sub' >> foo
$ git add foo
$ commit -a -m 'addfoo'
$ BASE=`pwd`
$ cd ..
$ mkdir git-repo6
$ cd git-repo6
$ git init-db >/dev/null 2>/dev/null
$ git submodule add ${BASE} >/dev/null 2>/dev/null
$ commit -a -m 'addsubmodule' >/dev/null 2>/dev/null
test non-tab whitespace .gitmodules
$ cat >> .gitmodules <<EOF
> [submodule "git-repo5"]
> path = git-repo5
> url = git-repo5
> EOF
$ git commit -q -a -m "weird white space submodule"
$ cd ..
$ hg convert git-repo6 hg-repo6
initializing destination hg-repo6 repository
scanning source...
sorting...
converting...
1 addsubmodule
0 weird white space submodule
updating bookmarks
$ rm -rf hg-repo6
$ cd git-repo6
$ git reset --hard 'HEAD^' > /dev/null
test missing .gitmodules
$ git submodule add ../git-repo4 >/dev/null 2>/dev/null
$ git checkout HEAD .gitmodules
$ git rm .gitmodules
rm '.gitmodules'
$ git commit -q -m "remove .gitmodules" .gitmodules
$ git commit -q -m "missing .gitmodules"
$ cd ..
$ hg convert git-repo6 hg-repo6 --traceback
fatal: Path '.gitmodules' does not exist in '*' (glob)
initializing destination hg-repo6 repository
scanning source...
sorting...
converting...
2 addsubmodule
1 remove .gitmodules
0 missing .gitmodules
warning: cannot read submodules config file in * (glob)
updating bookmarks
$ rm -rf hg-repo6
$ cd git-repo6
$ rm -rf git-repo4
$ git reset --hard 'HEAD^^' > /dev/null
$ cd ..
test invalid splicemap1
$ cat > splicemap <<EOF
> $VALIDID1
> EOF
$ hg convert --splicemap splicemap git-repo2 git-repo2-splicemap1-hg
initializing destination git-repo2-splicemap1-hg repository
abort: syntax error in splicemap(1): child parent1[,parent2] expected
[255]
test invalid splicemap2
$ cat > splicemap <<EOF
> $VALIDID1 $VALIDID2, $VALIDID2, $VALIDID2
> EOF
$ hg convert --splicemap splicemap git-repo2 git-repo2-splicemap2-hg
initializing destination git-repo2-splicemap2-hg repository
abort: syntax error in splicemap(1): child parent1[,parent2] expected
[255]
test invalid splicemap3
$ cat > splicemap <<EOF
> $INVALIDID1 $INVALIDID2
> EOF
$ hg convert --splicemap splicemap git-repo2 git-repo2-splicemap3-hg
initializing destination git-repo2-splicemap3-hg repository
abort: splicemap entry afd12345af is not a valid revision identifier
[255]
convert sub modules
$ hg convert git-repo6 git-repo6-hg
initializing destination git-repo6-hg repository
scanning source...
sorting...
converting...
0 addsubmodule
updating bookmarks
$ hg -R git-repo6-hg log -v
changeset: 0:* (glob)
bookmark: master
tag: tip
user: nottest <test@example.org>
date: Mon Jan 01 00:00:23 2007 +0000
files: .hgsub .hgsubstate
description:
addsubmodule
committer: test <test@example.org>
$ cd git-repo6-hg
$ hg up >/dev/null 2>/dev/null
$ cat .hgsubstate
* git-repo5 (glob)
$ cd git-repo5
$ cat foo
sub
$ cd ../..
make sure rename detection doesn't break removing and adding gitmodules
$ cd git-repo6
$ git mv .gitmodules .gitmodules-renamed
$ commit -a -m 'rename .gitmodules'
$ git mv .gitmodules-renamed .gitmodules
$ commit -a -m 'rename .gitmodules back'
$ cd ..
$ hg --config convert.git.similarity=100 convert -q git-repo6 git-repo6-hg
$ hg -R git-repo6-hg log -r 'tip^' -T "{desc|firstline}\n"
rename .gitmodules
$ hg -R git-repo6-hg status -C --change 'tip^'
A .gitmodules-renamed
R .hgsub
R .hgsubstate
$ hg -R git-repo6-hg log -r tip -T "{desc|firstline}\n"
rename .gitmodules back
$ hg -R git-repo6-hg status -C --change tip
A .hgsub
A .hgsubstate
R .gitmodules-renamed
convert the revision removing '.gitmodules' itself (and related
submodules)
$ cd git-repo6
$ git rm .gitmodules
rm '.gitmodules'
$ git rm --cached git-repo5
rm 'git-repo5'
$ commit -a -m 'remove .gitmodules and submodule git-repo5'
$ cd ..
$ hg convert -q git-repo6 git-repo6-hg
$ hg -R git-repo6-hg tip -T "{desc|firstline}\n"
remove .gitmodules and submodule git-repo5
$ hg -R git-repo6-hg tip -T "{file_dels}\n"
.hgsub .hgsubstate
convert using a different remote prefix
$ git init git-repo7
Initialized empty Git repository in $TESTTMP/git-repo7/.git/
$ cd git-repo7
$ touch a && git add a && git commit -am "commit a"
[master (root-commit) 8ae5f69] commit a
Author: nottest <test@example.org>
1 file changed, 0 insertions(+), 0 deletions(-)
create mode 100644 a
$ cd ..
$ git clone git-repo7 git-repo7-client
Cloning into 'git-repo7-client'...
done.
$ hg convert --config convert.git.remoteprefix=origin git-repo7-client hg-repo7
initializing destination hg-repo7 repository
scanning source...
sorting...
converting...
0 commit a
updating bookmarks
$ hg -R hg-repo7 bookmarks
master 0:03bf38caa4c6
origin/master 0:03bf38caa4c6
Run convert when the remote branches have changed
(there was an old bug where the local convert read branches from the server)
$ cd git-repo7
$ echo a >> a
$ git commit -am "move master forward"
[master 0c81947] move master forward
Author: nottest <test@example.org>
1 file changed, 1 insertion(+)
$ cd ..
$ rm -rf hg-repo7
$ hg convert --config convert.git.remoteprefix=origin git-repo7-client hg-repo7
initializing destination hg-repo7 repository
scanning source...
sorting...
converting...
0 commit a
updating bookmarks
$ hg -R hg-repo7 bookmarks
master 0:03bf38caa4c6
origin/master 0:03bf38caa4c6
damaged git repository tests:
In case the hard-coded hashes change, the following commands can be used to
list the hashes and their corresponding types in the repository:
cd git-repo4/.git/objects
find . -type f | cut -c 3- | sed 's_/__' | xargs -n 1 -t git cat-file -t
cd ../../..
damage git repository by renaming a commit object
$ COMMIT_OBJ=1c/0ce3c5886f83a1d78a7b517cdff5cf9ca17bdd
$ mv git-repo4/.git/objects/$COMMIT_OBJ git-repo4/.git/objects/$COMMIT_OBJ.tmp
$ hg convert git-repo4 git-repo4-broken-hg 2>&1 | grep 'abort:'
abort: cannot read tags from git-repo4/.git
$ mv git-repo4/.git/objects/$COMMIT_OBJ.tmp git-repo4/.git/objects/$COMMIT_OBJ
damage git repository by renaming a blob object
$ BLOB_OBJ=8b/137891791fe96927ad78e64b0aad7bded08bdc
$ mv git-repo4/.git/objects/$BLOB_OBJ git-repo4/.git/objects/$BLOB_OBJ.tmp
$ hg convert git-repo4 git-repo4-broken-hg 2>&1 | grep 'abort:'
abort: cannot read 'blob' object at 8b137891791fe96927ad78e64b0aad7bded08bdc
$ mv git-repo4/.git/objects/$BLOB_OBJ.tmp git-repo4/.git/objects/$BLOB_OBJ
damage git repository by renaming a tree object
$ TREE_OBJ=72/49f083d2a63a41cc737764a86981eb5f3e4635
$ mv git-repo4/.git/objects/$TREE_OBJ git-repo4/.git/objects/$TREE_OBJ.tmp
$ hg convert git-repo4 git-repo4-broken-hg 2>&1 | grep 'abort:'
abort: cannot read changes in 1c0ce3c5886f83a1d78a7b517cdff5cf9ca17bdd