annotate tests/test-convert-git.t @ 25787:d9133e89d39d

convert: allow customizing git remote prefix

Previously all git remotes were created as "remote/foo". This patch adds a
configuration option for deciding what the prefix should be. This is useful if
you want the bookmarks to be "origin/foo" like they are in git, or if you're
integrating with the remotenames extension and don't want the local remote/foo
bookmarks to overlap with the remote foo bookmarks.

#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='[e-mail]'; 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 <[e-mail]>
  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 <[e-mail]>
  date:        Mon Jan 01 00:00:21 2007 +0000
  files:       foo
  description:
  addfoo2
  
  committer: test <[e-mail]>
  
  
  changeset:   0:0735477b0224
  user:        test <[e-mail]>
  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 <[e-mail]>
  date:        Mon Jan 01 00:00:23 2007 +0000
  files:       .hgsub .hgsubstate
  description:
  addsubmodule
  
  committer: test <[e-mail]>
  
  

  $ 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 <[e-mail]>
   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

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