"Main branch "master" could not be found in your repository" but it's right there!

[mikepqr]

Description of the bug

I get an error (warning?) that the main branch could not be found every time I git sync after landing a change. I'm left on a detached HEAD (possibly this is expected?) and git sl fails (definitely not expected!). If I then explicitly checkout master I get back to a working state.

Expected behavior

git sync and git sl work without an error.

Actual behavior

$ git fetch
origin: Extents updated: 1283 transactions
origin: Updating from https://git.twitter.biz/source/objects/journals/32.bin
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100  307k  100  307k    0     0   739k      0 --:--:-- --:--:-- --:--:--  739k
Replaying transactions: 100% (1283/1283), done.
cannot delete non-empty directory: reference-transaction.d

$ git branch
* master

$ git sync
Attempting rebase in-memory...
[1/1] Skipped commit (was already applied upstream): a618c8d3 TNB. Move overnight build to early morning
branchless: processing 1 rewritten commit
The application panicked (crashed).
Message:  A fatal error occurred:
   0: Could not find repository main branch
Location:
   /Users/mleewilliams/.cargo/registry/src/github.com-1ecc6299db9ec823/git-branchless-lib-0.3.12/src/git/repo.rs:404
  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ SPANTRACE ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
   0: branchless::git::repo::get_main_branch_oid with self=<Git repository at: "/Users/mleewilliams/workspace/source/.git/">
      at /Users/mleewilliams/.cargo/registry/src/github.com-1ecc6299db9ec823/git-branchless-lib-0.3.12/src/git/repo.rs:412
   1: branchless::core::rewrite::rewrite_hooks::warn_abandoned with effects=<Output fancy=false> repo=<Git repository at: "/Users/mleewilliams/workspace/source/.git/"> conn=Connection { path: Some("/Users/mleewilliams/workspace/source/.git/branchless/db.sqlite3") } event_log_db=<EventLogDb>
      at /Users/mleewilliams/.cargo/registry/src/github.com-1ecc6299db9ec823/git-branchless-lib-0.3.12/src/core/rewrite/rewrite_hooks.rs:193
   2: branchless::core::rewrite::rewrite_hooks::hook_post_rewrite with effects=<Output fancy=false> git_run_info=<GitRunInfo path_to_git="git" working_directory="/Users/mleewilliams/workspace/source" env=not shown> rewrite_type="rebase"
      at /Users/mleewilliams/.cargo/registry/src/github.com-1ecc6299db9ec823/git-branchless-lib-0.3.12/src/core/rewrite/rewrite_hooks.rs:105
Suggestion:
The main branch "master" could not be found in your repository
at path: "/Users/mleewilliams/workspace/source/.git/".
These branches exist: []
Either create it, or update the main branch setting by running:
    git config branchless.core.mainBranch <branch>
Backtrace omitted. Run with RUST_BACKTRACE=1 environment variable to display it.
Run with RUST_BACKTRACE=full to include source snippets.
Location: /Users/mleewilliams/.cargo/registry/src/github.com-1ecc6299db9ec823/git-branchless-0.3.12/src/commands/mod.rs:298
Backtrace omitted. Run with RUST_BACKTRACE=1 environment variable to display it.
Run with RUST_BACKTRACE=full to include source snippets.
branchless: running command: git checkout 10cacf4f994e837bf97e25f9d99760f9c2be49e9
⠖ Syncing commit stacks (5.0s)                                                                                       ░░░░░░░░░░░░░░░░░░░░ 0/1
Previous HEAD position was a618c8d3e49a4 TNB. Move overnight build to early morning
HEAD is now at 10cacf4f994e8 Docbird: Edit 12086 applied automatically from browser, without review. AUTOMATED_COMMIT=true
branchless: processing checkout
In-memory rebase succeeded.
Synced a618c8d3 TNB. Move overnight build to early morning
(HEAD detached at 10cacf4f994e8)

$ git sl
The application panicked (crashed).
Message:  A fatal error occurred:
   0: Could not find repository main branch
Location:
   /Users/mleewilliams/.cargo/registry/src/github.com-1ecc6299db9ec823/git-branchless-lib-0.3.12/src/git/repo.rs:404
  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ SPANTRACE ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
   0: branchless::git::repo::get_main_branch_oid with self=<Git repository at: "/Users/mleewilliams/workspace/source/.git/">
      at /Users/mleewilliams/.cargo/registry/src/github.com-1ecc6299db9ec823/git-branchless-lib-0.3.12/src/git/repo.rs:412
   1: git_branchless::commands::smartlog::smartlog with effects=<Output fancy=true> git_run_info=<GitRunInfo path_to_git="git" working_directory="/Users/mleewilliams/workspace/source" env=not shown> options=SmartlogOptions { show_hidden_commits: false, only_show_branches: false }
      at /Users/mleewilliams/.cargo/registry/src/github.com-1ecc6299db9ec823/git-branchless-0.3.12/src/commands/smartlog.rs:533
Suggestion:
The main branch "master" could not be found in your repository
at path: "/Users/mleewilliams/workspace/source/.git/".
These branches exist: []
Either create it, or update the main branch setting by running:
    git config branchless.core.mainBranch <branch>
Backtrace omitted. Run with RUST_BACKTRACE=1 environment variable to display it.
Run with RUST_BACKTRACE=full to include source snippets.
Location: /Users/mleewilliams/.cargo/registry/src/github.com-1ecc6299db9ec823/git-branchless-0.3.12/src/commands/mod.rs:298
Backtrace omitted. Run with RUST_BACKTRACE=1 environment variable to display it.
Run with RUST_BACKTRACE=full to include source snippets.
(HEAD detached at 10cacf4f994e8)

$ git checkout master
Branch 'master' set up to track remote branch 'master' from 'origin'.
Switched to a new branch 'master'
Your branch is up to date with 'origin/master'.
branchless: processing checkout

$ git sl
⋮
◆ 10cacf4 2m (remote origin/master, ᐅ master) Docbird: Edit 12086 applied automatically from browser, without review. AUTOMATED_COMMIT=true

Version of rustc

rustc 1.59.0

Automated bug report

#### Software version

git-branchless 0.3.12

#### Operating system

macOS 12.5 (Darwin 21.6.0)

#### Command-line

```bash
/Users/mleewilliams/.cargo/bin/git-branchless bug-report 

Environment variables

SHELL=/bin/bash
EDITOR=nvim

Git version

> git version 
git version 2.25.0.853.g5575ef6-twtrsrc

Events

Show 5 events

Event ID: 451, transaction ID: 475

1. RefUpdateEvent { timestamp: 1658965620.970999, event_tx_id: EventTransactionId(475), ref_name: "HEAD", old_oid: 10cacf4f994e837bf97e25f9d99760f9c2be49e9, new_oid: 10cacf4f994e837bf97e25f9d99760f9c2be49e9, message: None }

:
@ 10cacf4 24m (redacted-ref-0) xxxxxxxx xxxx xxxxx xxxxxxx xxxxxxxxxxxxx xxxx xxxxxxxx xxxxxxx xxxxxxx xxxxxxxxxxxxxxxxxxxxx
:
O 3d197ce 3m (remote origin/master) xxxxxxxxxxxxxxxxxx xxx xxxx xxxxx xxxxxxxx

Event ID: 449, transaction ID: 474

1. RewriteEvent { timestamp: 1658965570.51185, event_tx_id: EventTransactionId(474), old_commit_oid: a618c8d3e49a48df84c072281958c4059ce820d6, new_commit_oid: 0000000000000000000000000000000000000000 }
2. RefUpdateEvent { timestamp: 1658965596.124385, event_tx_id: EventTransactionId(474), ref_name: "HEAD", old_oid: a618c8d3e49a48df84c072281958c4059ce820d6, new_oid: 10cacf4f994e837bf97e25f9d99760f9c2be49e9, message: None }

:
@ 10cacf4 24m (redacted-ref-0) xxxxxxxx xxxx xxxxx xxxxxxx xxxxxxxxxxxxx xxxx xxxxxxxx xxxxxxx xxxxxxx xxxxxxxxxxxxxxxxxxxxx
:
O 3d197ce 3m (remote origin/master) xxxxxxxxxxxxxxxxxx xxx xxxx xxxxx xxxxxxxx

Event ID: 448, transaction ID: 472

1. RewriteEvent { timestamp: 1658944229.534632, event_tx_id: EventTransactionId(472), old_commit_oid: 2b250d3c4fd0fcf156cc8eaf5f4b95814c9fcc22, new_commit_oid: a618c8d3e49a48df84c072281958c4059ce820d6 }

:
@ 10cacf4 24m (redacted-ref-0) xxxxxxxx xxxx xxxxx xxxxxxx xxxxxxxxxxxxx xxxx xxxxxxxx xxxxxxx xxxxxxx xxxxxxxxxxxxxxxxxxxxx
:
O 3d197ce 3m (remote origin/master) xxxxxxxxxxxxxxxxxx xxx xxxx xxxxx xxxxxxxx

Event ID: 447, transaction ID: 471

1. CommitEvent { timestamp: 1658944228.0, event_tx_id: EventTransactionId(471), commit_oid: NonZeroOid(a618c8d3e49a48df84c072281958c4059ce820d6) }

:
@ 10cacf4 24m (redacted-ref-0) xxxxxxxx xxxx xxxxx xxxxxxx xxxxxxxxxxxxx xxxx xxxxxxxx xxxxxxx xxxxxxx xxxxxxxxxxxxxxxxxxxxx
:
O 3d197ce 3m (remote origin/master) xxxxxxxxxxxxxxxxxx xxx xxxx xxxxx xxxxxxxx

Event ID: 446, transaction ID: 470

1. CommitEvent { timestamp: 1658943942.0, event_tx_id: EventTransactionId(470), commit_oid: NonZeroOid(2b250d3c4fd0fcf156cc8eaf5f4b95814c9fcc22) }

:
@ 10cacf4 24m (redacted-ref-0) xxxxxxxx xxxx xxxxx xxxxxxx xxxxxxxxxxxxx xxxx xxxxxxxx xxxxxxx xxxxxxx xxxxxxxxxxxxxxxxxxxxx
:
O 3d197ce 3m (remote origin/master) xxxxxxxxxxxxxxxxxx xxx xxxx xxxxx xxxxxxxx

```

Version of git-branchless

No response

Version of git

No response

[arxanas]

Hi @mikepqr, thanks for reporting! I was able to reproduce the issue and put up a fix in https://github.com/arxanas/git-branchless/pull/485. Can you test it out (instructions) and confirm that it resolves the bug?

[mikepqr]

Awesome! Happy to test but I'm afraid I need a little basic cargo support to unblock:

$ cargo install --locked --git https://github.com/arxanas/git-branchless --branch arxanas/sync git-branchless --force
    Updating git repository `https://github.com/arxanas/git-branchless`
  Installing git-branchless v0.3.12 (https://github.com/arxanas/git-branchless?branch=arxanas/sync#e3ccc646)
    Updating crates.io index
error: failed to select a version for the requirement `libgit2-sys = "^0.14.0"`
candidate versions found which didn't match: 0.13.2+1.4.2, 0.13.1+1.4.2, 0.13.0+1.4.1, ...
location searched: crates.io index
required by package `git2 v0.15.0`
    ... which satisfies dependency `git2 = "^0.15.0"` (locked to 0.15.0) of package `git-branchless-lib v0.3.12 (/Users/mleewilliams/.cargo/git/checkouts/git-branchless-f6bbbe393421e02f/e3ccc64/git-branchless-lib)`
    ... which satisfies path dependency `lib` (locked to 0.3.12) of package `git-branchless v0.3.12 (/Users/mleewilliams/.cargo/git/checkouts/git-branchless-f6bbbe393421e02f/e3ccc64/git-branchless)`

[arxanas]

@mikepqr sorry about that, the error message is quite bad here. You need to update your version of Rust/Cargo. cargo in an older version can't resolve these dependencies properly, which produces this error message. git-branchless is marked as requiring Rust 1.61.0 or later, but cargo tries to resolve dependencies before it can check for this. I'll add a note to this Troubleshooting section too.

[arxanas]

By the way, as a workaround, you can try committing to branches other than master, or try not committing to master at all and using a branchless strategy (i.e. run git checkout --detach before committing). This seems to be happening when you make changes to master and then apply them upstream and run git sync.

[mikepqr]

Thanks! I've upgraded to #485 and will let you know how I get on.

[arxanas]

Closed in #593.