main branch rewritten as 00000000

[ppwwyyxx]

Description of the bug

1. Create a commit locally with a branch name and create a PR from it
2. Merge the PR on github. With fast-forward merge (no merge commit)
3. In the local repo, do git commit --amend, then immediately save and exit. Do not apply any actual changes in the amend window.
4. do git restack
5. do git sync --pull

Expected behavior

No "rewritten as 000000" appears

Actual behavior

Version of rustc

rustc 1.73.0 (cc66ad468 2023-10-03)

Automated bug report

#### Software version

git-branchless 0.8.0

#### Command-line

```bash
/home/XXX/.cargo/bin/git-branchless bug-report 

Environment variables

SHELL=/bin/zsh
EDITOR=nvim

Git version

> git version 
git version 2.25.1

Hooks

Show 7 hooks

Hook post-applypatch

#!/bin/sh
## START BRANCHLESS CONFIG

git branchless hook post-applypatch "$@"

## END BRANCHLESS CONFIG

Hook post-checkout

#!/bin/sh
## START BRANCHLESS CONFIG

git branchless hook post-checkout "$@"

## END BRANCHLESS CONFIG

Hook post-commit

#!/bin/sh
## START BRANCHLESS CONFIG

git branchless hook post-commit "$@"

## END BRANCHLESS CONFIG

Hook post-merge

#!/bin/sh
## START BRANCHLESS CONFIG

git branchless hook post-merge "$@"

## END BRANCHLESS CONFIG

Hook post-rewrite

#!/bin/sh
## START BRANCHLESS CONFIG

git branchless hook post-rewrite "$@"

## END BRANCHLESS CONFIG

Hook pre-auto-gc

#!/bin/sh
## START BRANCHLESS CONFIG

git branchless hook pre-auto-gc "$@"

## END BRANCHLESS CONFIG

Hook reference-transaction

#!/bin/sh
## START BRANCHLESS CONFIG

# Avoid canceling the reference transaction in the case that `branchless` fails
# for whatever reason.
git branchless hook reference-transaction "$@" || (
echo 'branchless: Failed to process reference transaction!'
echo 'branchless: Some events (e.g. branch updates) may have been lost.'
echo 'branchless: This is a bug. Please report it.'
)

## END BRANCHLESS CONFIG

Events

Show 5 events

Event ID: 38, transaction ID: 25 (message: sync)

1. RefUpdateEvent { timestamp: 1707671477.1453016, event_tx_id: EventTransactionId(25), ref_name: ReferenceName("refs/heads/redacted-ref-0"), old_oid: 79b98014e60919903c48c9971b3966322f994fa9, new_oid: 0000000000000000000000000000000000000000, message: None }
2. RewriteEvent { timestamp: 1707671477.1720936, event_tx_id: EventTransactionId(25), old_commit_oid: 79b98014e60919903c48c9971b3966322f994fa9, new_commit_oid: 0000000000000000000000000000000000000000 }
3. WorkingCopySnapshot { timestamp: 1707671477.1937, event_tx_id: EventTransactionId(25), head_oid: 79b98014e60919903c48c9971b3966322f994fa9, commit_oid: NonZeroOid(d07687388112a95fb07afb1cfaaba9dfc1a2b1e1), ref_name: None }
4. RefUpdateEvent { timestamp: 1707671477.2118502, event_tx_id: EventTransactionId(25), ref_name: ReferenceName("HEAD"), old_oid: 79b98014e60919903c48c9971b3966322f994fa9, new_oid: 0c219685cd7ef34f297fc191650a03a8ca69df68, message: None }

:
% 0c21968 6m (rewritten as 00000000) (master) xxxxxxxx

Event ID: 37, transaction ID: 23 (message: restack)

1. RefUpdateEvent { timestamp: 1707671457.734186, event_tx_id: EventTransactionId(23), ref_name: ReferenceName("refs/heads/redacted-ref-0"), old_oid: 154b1cbbbf6a8b2767e14aaef85976799d1459b0, new_oid: 79b98014e60919903c48c9971b3966322f994fa9, message: None }

:
% 0c21968 6m (rewritten as 79b98014) (master) xxxxxxxx

Event ID: 36, transaction ID: 22 (message: hook-post-rewrite)

1. RewriteEvent { timestamp: 1707671457.6811366, event_tx_id: EventTransactionId(22), old_commit_oid: 154b1cbbbf6a8b2767e14aaef85976799d1459b0, new_commit_oid: 79b98014e60919903c48c9971b3966322f994fa9 }

:
% 0c21968 6m (rewritten as 79b98014) (master) xxxxxxxx

Event ID: 35, transaction ID: 21 (message: post-commit)

1. CommitEvent { timestamp: 1707671456.0, event_tx_id: EventTransactionId(21), commit_oid: NonZeroOid(79b98014e60919903c48c9971b3966322f994fa9) }

:
% 0c21968 6m (rewritten as 154b1cbb) (master) xxxxxxxx

Event ID: 31, transaction ID: 20 (message: reword)

1. RefUpdateEvent { timestamp: 1707671451.2447162, event_tx_id: EventTransactionId(20), ref_name: ReferenceName("refs/heads/redacted-ref-0"), old_oid: 0c219685cd7ef34f297fc191650a03a8ca69df68, new_oid: 154b1cbbbf6a8b2767e14aaef85976799d1459b0, message: None }
2. RewriteEvent { timestamp: 1707671451.2619314, event_tx_id: EventTransactionId(20), old_commit_oid: 0c219685cd7ef34f297fc191650a03a8ca69df68, new_commit_oid: 154b1cbbbf6a8b2767e14aaef85976799d1459b0 }
3. WorkingCopySnapshot { timestamp: 1707671451.2790852, event_tx_id: EventTransactionId(20), head_oid: 0c219685cd7ef34f297fc191650a03a8ca69df68, commit_oid: NonZeroOid(71683f298583a6df722ff286ae5dc6cd18a7a250), ref_name: None }
4. RefUpdateEvent { timestamp: 1707671451.2962728, event_tx_id: EventTransactionId(20), ref_name: ReferenceName("HEAD"), old_oid: 0c219685cd7ef34f297fc191650a03a8ca69df68, new_oid: 154b1cbbbf6a8b2767e14aaef85976799d1459b0, message: None }

:
% 0c21968 6m (rewritten as 154b1cbb) (master) xxxxxxxx

```

Version of git-branchless

No response

Version of git

No response