hg2git-heads file is missing if working with bare repository

[asergunov]

To reproduce on 5b7ca5a (current master)

mkdir repo.git
(cd repo.git && git init --bare --quiet && git config --local --bool core.ignoreCase "false" && hg-fast-export.sh -r $HG_REPO_PATH)
if [ ! -f repo.git/hg2git-heads ]; then
    echo hg2git-heads file is missing in repo.git
    exit 1
fi

So second call gives me an error

Error: Branch [master] already exists and was not created by hg-fast-export, export would overwrite unrelated branch

[asergunov]

Same behaviour on non bare repo

[asergunov]

I found I had an error

error: cannot lock ref 'refs/heads/TA836_-_Add_checkbox_Export>Output>End_Wall_Profile_Extention': Unable to create 'repo.git/./refs/heads/TA836_-_Add_checkbox_Export>Output>End_Wall_Profile_Extention.lock': Invalid argument

[frej]

A branch mapping file -B is probably what you want for handling this. Feel free to close this issue if that resolves your problem.

[asergunov]

Thank you for reply @frej You right. This will solve that problem.

Usability wise: Was trying with branches.map (by error message)

"TA836_-_Add_checkbox_Export>Output>End_Wall_Profile_Extention"="TA836_-_Add_checkbox_Export-Output-End_Wall_Profile_Extention"```

But it needs original branch name. And only way to find which branch it was is to remove repo and start again. I mean it will be nice to have kind-of log file somewhere with branch mapping.

Also it's not clear what to do if it will happen again with other branch or other error. Documentation says I should use

hg-reset.sh -R <revision>

But is it any way to find out what revision I should reset to? I mean is the latest successful revision stored anywhere?

[frej]

Fast-export doesn't update its state files unless git fast-import terminates successfully, that's why you ended up with a missing hg2git-heads.

To create a branch-map, your best bet is to ask Mercurial about the name of the branches: hg branches in the Mercurial repo.

But is it any way to find out what revision I should reset to?

In this case you have not had a single successful conversion so your only solution is to start from scratch. Personally I have never used hg-reset as it is something I inherited with the project, sorry. I guess you could use the latest Mercurial revision (hg log) and see what it says.

[asergunov]

I want to use this script as migration solution to let developers work with mercurial but let CICD use git. So plan is to run jobs by timer. Job should :

• hg pull
• <hg-fast-export-magic-here>
• git push

So it's something like

SUCCESSFULL_REVISION=0
if [ -f $GIT_REPO_PATH/hg2git-mapping ]; then
    SUCCESSFULL_REVISION=$(tac $GIT_REPO_PATH/hg2git-mapping | awk '{print $2; exit}')
fi

(cd $GIT_REPO_PATH && $SCRIPT_DIR/fast-export/hg-fast-export.sh -r $HG_REPO_PATH -A $SCRIPT_DIR/authors.map -B $SCRIPT_DIR/branches.map --hgtags && git push $GIT_REMOTE_REPO --all || echo Rollback to revision $SUCCESSFULL_REVISION && $SCRIPT_DIR/fast-export/hg-reset.sh -R $SUCCESSFULL_REVISION) 

But you right again hg-reset.sh doesn't really work

Rollback to revision 6666
Using last hg repository "<>"
Traceback (most recent call last):
  File "<>\fast-export\hg-reset.py", line 118, in <module>
    stale,changed,unchanged=get_branches(ui,repo,heads_cache,marks_cache,mapping_cache,options.revision+1)
  File "<>\fast-export\hg-reset.py", line 46, in get_branches
    del stale[branch]
KeyError: b'<original branch name here>'

[asergunov]

So here it should be transformed branch name but used original one https://github.com/frej/fast-export/blob/5b7ca5aaece48e3d05b63a393f5011df1d8ec69d/hg-reset.py#L46

[asergunov]

So I'm using full copy of repo

echo "Backup repo..." && cp -r $GIT_REPO_PATH $GIT_REPO_PATH.backup && echo 

(\
    cd $GIT_REPO_PATH && \
    $SCRIPT_DIR/fast-export/hg-fast-export.sh -r $HG_REPO_PATH -A $SCRIPT_DIR/authors.map -B $SCRIPT_DIR/branches.map --hgtags && \
    git push $GIT_REMOTE_REPO --all && \
    rm -rf $GIT_REPO_PATH.backup \
) || \
(\
    echo Rollback... && \
    rm -rf $GIT_REPO_PATH && \
    mv $GIT_REPO_PATH.backup $GIT_REPO_PATH \
)