> On 19 Jun 2017, at 10:46, Patrick Lehmann <patrick.lehm...@plc2.de> wrote: > > Hello, > > I wrote a Bash script to recover branch names after Git operations have > create detached HEADs in a Git repository containing lots of Git submodules. > The script works recursively.
I did run into this situation myself and therefore I understand your motivation. I've CC'ed Stefan as he is a Submodule expert! > I would like to see: > a) that script or algorithm being integrated into Git by default > b) that as a default behavior for all Git operations creating detached HEADs > > That's the command: > -------------------------------- > git submodule foreach --recursive 'HEAD=$(git branch --list | head -n 1); if > [[ "$HEAD" == *HEAD* ]]; then REF=$(git rev-parse HEAD); FOUND=0; for Branch > in $(git branch --list | grep "^ " | sed -e "s/ //" ); do if [[ "$(git > rev-parse "$Branch")" == $REF ]]; then echo -e " \e[36mCheckout > $Branch...\e[0m"; git checkout $Branch; FOUND=1; break; fi done; if [[ $FOUND > -eq 0 ]]; then echo -e " \e[31mNo matching branch found.\e[0m"; fi else echo > -e " \e[36mNothing to do.\e[0m"; fi' > -------------------------------- > > How does it work: > 1. It uses git submodule foreach to dive into each Git submodule and execute > a series of Bash commands. > 2. It's reading the list of branches and checks if the submodule is in > detached mode. The first line contains the string HEAD. > 3. Retrieve the hash of the detached HEAD > 4. Iterate all local branches and get their hashes > 5. Compare the branch hashes with the detached HEAD's hash. If it matches do > a checkout. If there are multiple branches with the same hash then your script would pick the first one. Can you imagine a situation where this would be a problem? Plus, you are looking only at local branches. Wouldn't it make sense to look at remote branches, too? > 6. Report if no branch name was found or if a HEAD was not in detached mode. > > The Bash code with line breaks and indentation: > -------------------------------- > HEAD=$(git branch --list | head -n 1) > if [[ "$HEAD" == *HEAD* ]]; then > REF=$(git rev-parse HEAD) > FOUND=0 > for Branch in $(git branch --list | grep "^ " | sed -e "s/ //" ); do There is a convenient "git for-each-ref" function to iterate over branches in scripts. See here an example: https://github.com/larsxschneider/scotty/blob/master/admin/oss-fork.sh#L88 > if [[ "$(git rev-parse "$Branch")" == $REF ]]; then > echo -e " \e[36mCheckout $Branch...\e[0m" > git checkout $Branch > FOUND=1 > break > fi > done > if [[ $FOUND -eq 0 ]]; then > echo -e " \e[31mNo matching branch found.\e[0m" > fi > else > echo -e " \e[36mNothing to do.\e[0m" > fi > -------------------------------- > > Are their any chances to get it integrated into Git? > > I tried to register that code as a Git alias, but git config complains about > quote problem not showing where. It neither specifies if it's a single or > double quote problem. Any advice on how to register that piece of code as an > alias? Try to escape ". See here for an example: https://github.com/Autodesk/enterprise-config-for-git/blob/master/config.include#L76-L94 > If wished, I think I could expand the script to also recover hash values to > Git tags if no branch was found. It would be indeed nice to see the tagged version on my prompt. -- Submodule processing is already quite slow if you have many of them. I wonder how much this approach would affect the performance. - Lars
