Handle get_default_branch failure with fallback to HEAD

[blooop]

Summary

• Wrap get_default_branch() in try/except in ensure_branch() so workspace creation remains robust when the default branch cannot be resolved (network issues, misconfigured repos)
• Fall back to "HEAD" on error or empty/falsy return value
• Tighten test_branch_custom_start_point to assert no remote push occurs when create_remote=False

Addresses review feedback from #31:

• sourcery-ai comment 1: handle failures from get_default_branch
• sourcery-ai comment 2: assert no remote operations in custom start_point test

Test plan

• Added test for get_default_branch raising an exception → falls back to "HEAD"
• Added test for get_default_branch returning empty string → falls back to "HEAD"
• Added mock_push.assert_not_called() to test_branch_custom_start_point
• All 70 affected tests pass

🤖 Generated with Claude Code

Summary by Sourcery

Handle failures when resolving a repository’s default branch during workspace branch setup and tighten test coverage around branch creation behavior.

Bug Fixes:

• Ensure workspace branch creation falls back to using HEAD when resolving the default branch fails or returns an empty value, preventing errors during ensure_branch.

Tests:

• Add tests verifying ensure_branch falls back to HEAD when get_default_branch raises or returns an empty string.
• Strengthen branch manager tests to assert no remote push occurs when create_remote is False for custom start points.

[sourcery-ai]

Reviewer's Guide

Adds robust handling around default-branch resolution in workspace cloning by falling back to HEAD when the default branch cannot be determined, and strengthens branch manager tests to verify no remote push occurs when create_remote is False.

Sequence diagram for ensure_branch default_branch fallback handling

sequenceDiagram
    participant WorkspaceClone
    participant RepoManager
    participant WorktreeBranchManager

    WorkspaceClone->>RepoManager: get_default_branch(owner, repo)
    alt get_default_branch succeeds with non_empty_branch
        RepoManager-->>WorkspaceClone: default_branch
        WorkspaceClone->>WorktreeBranchManager: ensure_branch_exists(bare_path, branch, create_remote=False, start_point=default_branch, use_local_refs=True)
    else get_default_branch raises_exception
        RepoManager--xWorkspaceClone: Exception
        WorkspaceClone->>WorkspaceClone: log warning Failed to resolve default branch
        WorkspaceClone->>WorktreeBranchManager: ensure_branch_exists(bare_path, branch, create_remote=False, start_point="HEAD", use_local_refs=True)
    else get_default_branch returns_empty_or_falsy
        RepoManager-->>WorkspaceClone: ""
        WorkspaceClone->>WorktreeBranchManager: ensure_branch_exists(bare_path, branch, create_remote=False, start_point="HEAD", use_local_refs=True)
    end

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Class diagram for WorkspaceClone ensure_branch collaborators

classDiagram
    class WorkspaceClone {
        repo_manager
        branch_manager
        ensure_branch(owner, repo, branch) void
    }

    class RepoManager {
        get_default_branch(owner, repo) str
    }

    class WorktreeBranchManager {
        ensure_branch_exists(bare_path, branch, create_remote, start_point, use_local_refs) void
    }

    WorkspaceClone --> RepoManager : uses
    WorkspaceClone --> WorktreeBranchManager : uses

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File-Level Changes

Change	Details	Files
Harden ensure_branch default-branch resolution to tolerate failures and empty responses, falling back to HEAD.	Wrap get_default_branch invocation in try/except and log a warning when resolution fails. Allow default_branch to be None on error and pass default_branch or 'HEAD' as the start_point to branch creation. Preserve existing fetch-before-ensure behavior and local-refs usage while making start point selection more robust.	devlaunch/worktree/workspace_clone.py
Add regression tests for default-branch failure/empty handling and for ensuring no remote push when create_remote is False with a custom start point.	Add tests that verify ensure_branch falls back to 'HEAD' when get_default_branch raises or returns an empty string. Extend test_branch_custom_start_point to mock push_branch_to_remote and assert it is not called when create_remote is False. Keep existing expectations on branch creation calls to ensure behavior remains consistent aside from the new guarantees.	test/test_workspace_clone.py test/test_worktree_branch_manager.py

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[sourcery-ai]

Hey - I've left some high level feedback:

• In ensure_branch, consider narrowing the except Exception around get_default_branch to the specific error types you expect (or at least repository-related ones) so that unexpected failures don’t get silently masked with a fallback to HEAD.
• When logging Failed to resolve default branch, it may be useful to include owner/repo in the log message to make troubleshooting easier when multiple repositories are being managed.

Prompt for AI Agents

Please address the comments from this code review:

## Overall Comments
- In `ensure_branch`, consider narrowing the `except Exception` around `get_default_branch` to the specific error types you expect (or at least repository-related ones) so that unexpected failures don’t get silently masked with a fallback to `HEAD`.
- When logging `Failed to resolve default branch`, it may be useful to include `owner`/`repo` in the log message to make troubleshooting easier when multiple repositories are being managed.

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 83.09%. Comparing base (54ce575) to head (85aa2eb).

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #35      +/-   ##
==========================================
+ Coverage   83.04%   83.09%   +0.05%     
==========================================
  Files           9        9              
  Lines        1197     1201       +4     
==========================================
+ Hits          994      998       +4     
  Misses        203      203              

Files with missing lines	Coverage Δ
devlaunch/worktree/workspace_clone.py	89.38% <100.00%> (+0.38%)	⬆️

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[blooop]

Closing as superseded — the fallback landed, in a better place.

This PR wraps the call site so a raising get_default_branch degrades to start_point="HEAD". On current main that try/except would be dead code: get_default_branch (devlaunch/worktree/repo_manager.py:320-350) no longer raises for those exceptions. It catches (OSError, SubprocessError, TimeoutExpired) itself and ends with an unconditional return "main", so every caller gets a branch name or nothing at all.

Different design from the one proposed, and strictly better: one fallback inside the function rather than one per caller, so a new caller cannot forget it.

Mechanically it also cannot merge — 209 commits behind main, conflicting, and its CI predates the gate job that is now a required check, so the required check never appears at all.