git-import-srpm: add script to create source branches from srpm repository.

[casasnovas]

On Debian derivatives, you'll need:
sudo apt-get install rpm

Simply run it inside a SRPM git repository and give it a revision (can be tag, branch, sha1, ...), e.g.:

CODE_REPO_PATH=/path/to/linux/repo SRPM_REPO_PATH=/path/kernel/srpm/repo git-import-srpm XS-8.2.1

To import all releases as branches, just pass --all:

git-import-srpm --all

By default, the SRPM_REPO_PATH is the current working directory. If no CODE_REPO_PATH is given, a default path is inferred that is ${SRPM_REPO_PATH}/../(linux|xen|qemu) (depending on the package being imported).

The script was used import all branches of qemu, xen and the Linux kernel released in current and prior XCP versions, e.g.:

• xen branch example: https://github.com/xcp-ng/xen/tree/xen/xcpng-4.17.5-23.1/base
• qemu branch example: https://github.com/xcp-ng/qemu-dp/tree/qemu/xcpng-4.2.1-5.2.15.2/base
• linux branch example: https://github.com/xcp-ng/linux/tree/linux/xcpng-4.19.19-8.0.32.1/base

The script gives idempotent runs, reconstructed git sha1 will stay the same across runs for a given srpm revision. The script will not touch any of your repository worktrees or indexes, so it is safe to run any time even if you are working in the source repo (patches are applied separately in a temporary worktree).

Note that for each srpm revision, the script will create two branches in the source repository, in the form:

/(xcpng|xenserver)-/(pre-base|base)

The pre-base ref will point to the upstream commit that was used as basis by the source RPM before applying patches. Effectively, the patch-set applied by a source rpm can be rev-listed with git log /pre-base../base which allows see-ing how the patchset evolved over time.

You can use git-review-rebase easily on two imports to see the changes in the patch-queues.

Original pull-request was on the
xcp repository but after discussion with the OS&Platform team, it was agreed it is better to have it here. Sub-sequent work could try and add github workflows to run this script automatically when we notice new SRPMs from XenServer, but right now it is a manual process (so is running import_srpm.py).

[fallen]

This is a PR to merge in another non-main branch?
Is this on purpose?

[casasnovas]

This is a PR to merge in another non-main branch? Is this on purpose?

This is to merge to main, but I didn't find a nicer way to stack PR on top of each other than chosing its parent branch. If this gets approved before the others, I'll just rebase that one commit on top of main before pushing.

[fallen]

This is a PR to merge in another non-main branch? Is this on purpose?

This is to merge to main, but I didn't find a nicer way to stack PR on top of each other than chosing its parent branch. If this gets approved before the others, I'll just rebase that one commit on top of main before pushing.

Oh, ok!

[casasnovas]

This is a PR to merge in another non-main branch? Is this on purpose?

This is to merge to main, but I didn't find a nicer way to stack PR on top of each other than chosing its parent branch. If this gets approved before the others, I'll just rebase that one commit on top of main before pushing.

Oh, ok!

I did the rebase now to make it less confusing. edit: for the other branches, that one actually depends on the prior two as it changes the README.md file, so I prefer to wait for the other two PRs to be merged to avoid having to deal with conflicts in the README.md.