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heartwood/radicle-cli/examples/git/git-push-diverge.md
T
Fintan Halpenny 82a53e3a53 radicle: UserInfo for Repository::create
The fetch V2 improvements introduced a `UserInfo` type that is used to
set the Git config's name and email when cloning a repository. This
`UserInfo` can also be used when creating a new `Repository`.

The `Storage` type now takes a `UserInfo` so that it can be passed to
`Repository::create`, for creating a new repository.

For testing, this requires adding a new `fixtures::user` so that
testing `Storage` instances can be easily constructed.

It also means that the `radicle-cli` tests all changed with new SHAs
since the name and email are used as part of the hashing input.

N.b. the order of the timelines while testing the identity cob
changed. It's not clear why that is.

Signed-off-by: Fintan Halpenny <fintan.halpenny@gmail.com>
X-Clacks-Overhead: GNU Terry Pratchett
2023-11-09 16:43:34 +01:00

3.0 KiB

Let's see what happens if we try to push a head which diverges from the canonical head.

First we add a second delegate, Bob, to our repo:

$ rad id update --title "Add Bob" --description "" --delegate did:key:z6Mkt67GdsW7715MEfRuP4pSZxJRJh6kj6Y48WRqVv4N1tRk --repo rad:z42hL2jL4XNk6K8oHQaSWfMgCL7ji -q
c036c0d89ce26aef3ad7da402157dba16b5163b4
$ rad remote add did:key:z6Mkt67GdsW7715MEfRuP4pSZxJRJh6kj6Y48WRqVv4N1tRk
✓ Remote bob@z6Mkt67GdsW7715MEfRuP4pSZxJRJh6kj6Y48WRqVv4N1tRk added
✓ Remote-tracking branch bob@z6Mkt67GdsW7715MEfRuP4pSZxJRJh6kj6Y48WRqVv4N1tRk/master created for z6Mkt67…v4N1tRk

Then, as Bob, we commit some code on top of the canonical head:

$ rad sync --fetch
✓ Fetching rad:z42hL2jL4XNk6K8oHQaSWfMgCL7ji from z6MknSL…StBU8Vi..
✓ Fetched repository from 1 seed(s)
$ rad inspect --delegates
did:key:z6MknSLrJoTcukLrE435hVNQT4JUhbvWLX4kUzqkEStBU8Vi (alice)
did:key:z6Mkt67GdsW7715MEfRuP4pSZxJRJh6kj6Y48WRqVv4N1tRk (bob)
$ git commit -m "Third commit" --allow-empty -q
$ git push rad
$ git branch -arv
  alice@z6MknSLrJoTcukLrE435hVNQT4JUhbvWLX4kUzqkEStBU8Vi/master f2de534 Second commit
  rad/master                                                    319a7dc Third commit

As Alice, we fetch that code, but commit on top of our own master, which is no longer canonical, since Bob pushed a more recent commit, and the threshold is 1:

$ git fetch bob@z6Mkt67GdsW7715MEfRuP4pSZxJRJh6kj6Y48WRqVv4N1tRk
$ git branch -arv
  bob@z6Mkt67GdsW7715MEfRuP4pSZxJRJh6kj6Y48WRqVv4N1tRk/master 319a7dc Third commit
  rad/master                                                  f2de534 Second commit
$ git commit -m "Third commit by Alice" --allow-empty -q

If we try to push now, we get an error with a hint, telling us that we need to integrate Bob's changes before pushing ours:

$ git push rad
hint: you are attempting to push a commit that would cause your upstream to diverge from the canonical head
hint: to integrate the remote changes, run `git pull --rebase` and try again
error: refusing to update branch to commit that is not a descendant of canonical head
error: failed to push some refs to 'rad://z42hL2jL4XNk6K8oHQaSWfMgCL7ji/z6MknSLrJoTcukLrE435hVNQT4JUhbvWLX4kUzqkEStBU8Vi'

We do that, and notice that we're now able to push our code:

$ git pull --rebase
$ git log --oneline
f6cff86 Third commit by Alice
319a7dc Third commit
f2de534 Second commit
08c788d Initial commit
$ git push rad
To rad://z42hL2jL4XNk6K8oHQaSWfMgCL7ji/z6MknSLrJoTcukLrE435hVNQT4JUhbvWLX4kUzqkEStBU8Vi
   f2de534..f6cff86  master -> master

One thing of note is that we can't push an older commit either, by default:

$ git reset --hard HEAD^ -q
$ git push -f

We have to use the allow.rollback option:

$ git push -f -o allow.rollback
To rad://z42hL2jL4XNk6K8oHQaSWfMgCL7ji/z6MknSLrJoTcukLrE435hVNQT4JUhbvWLX4kUzqkEStBU8Vi
 + f6cff86...319a7dc master -> master (forced update)