It is difficult to find the parent-branch in git ...

My current solution:

git show-branch -a 2>/dev/null \
| grep '\*' \
| grep -v `git rev-parse --abbrev-ref HEAD` \
| head -n1 \
| perl -ple 's/\[[A-Za-z] -\d \][^\]] $//; s/^.*\[([^~^\]] ).*$/$1/'

Source: https://stackoverflow.com/a/74314172/633961

Why is it difficult to find the parent-branch in git?

This question is not about "how to solve this?". It is about "why is it not straight forward?"

CodePudding user response：

It's worth reading; https://git-scm.com/book/en/v2/Git-Internals-Git-References.

Then take a look at the content of .git/refs/heads/master or any equivalent file in that folder. It's just a file containing a commit hash. That's what a branch is.

The point is that the original commit hash or ref is not stored for a branch. Only the current commit hash is stored for the branch.

CodePudding user response：

git doesn't store anything about branches.

A commit is an object which points to its parent, and you will have a relation ship between commits, but a branch is just a name that points to a commit.

In standard git, there is no information stored which keep track of : "branch x was initially created from y, then was merged with branch z on june 16th, then was reset on that day, then ...".

You can only do guess work based on the current commit graph, and the current state of other branches.

This guess work leads to commands such as the one you quoted.

You should also note that depending on the way you manage branches in your own repository, some of these proxies may work for someone else but not for you.