fix(core): resolve --from ref to SHA to prevent git DWIM overriding branch name

[damianlewis]

Summary

• When --from <ref> matches a remote tracking branch name, git's guess-remote logic overrides the explicit -b flag and creates a tracking branch with the remote name instead of the requested name
• Fix resolves from_ref to a commit SHA before passing it to git worktree add -b, preventing git from matching it to a remote branch
• Uses git rev-parse --verify with an origin/ fallback, compatible with all supported git versions (2.17+)

Closes #146

Test plan

• All 330 existing BATS tests pass (same 9 pre-existing failures unrelated to this change)
• 7 new tests added covering all --from ref types:
  • --from <local-branch> — resolves to correct commit
  • --from <tag> — resolves to tagged commit
  • --from <commit-sha> — passes through correctly
  • --from <remote-branch-name> — uses requested branch name, not remote name (the bug)
  • --from <remote-branch-name> — starts at correct commit
  • --from with auto track mode — honours from_ref
  • --from <invalid-ref> — fails with error

Summary by CodeRabbit

• Bug Fixes

  • Improve worktree creation so branch references are reliably resolved to the intended commit, avoiding accidental selection of remote branches when names overlap.

• Tests

  • Expanded tests covering worktree creation from local branches, remote branches, tags, commit SHAs, auto mode behavior, and invalid-reference error handling.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

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📥 Commits

Reviewing files that changed from the base of the PR and between 22d14d9 and e674c88.

📒 Files selected for processing (2)

• lib/core.sh
• tests/core_create_worktree.bats

🚧 Files skipped from review as they are similar to previous changes (2)

• tests/core_create_worktree.bats
• lib/core.sh

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Walkthrough

Resolves from_ref to an unambiguous commit SHA (tries from_ref, then origin/from_ref, then falls back) and uses that resolved_ref when creating worktrees to avoid Git's guess-remote behavior that can override -b when from_ref matches a remote branch name.

Changes

Cohort / File(s)	Summary
Core implementation lib/core.sh	Add resolved_ref resolution using git rev-parse --verify (try from_ref, then origin/from_ref, else fallback). Replace usages of from_ref with resolved_ref in worktree creation paths for none and auto track modes to prevent guess-remote from overriding -b.
Test coverage tests/core_create_worktree.bats	Add extensive tests for --from handling: local branch, lightweight tag, annotated tag, commit SHA, remote-tracking ref, auto mode behavior, and invalid from_ref error handling; assert correct starting commits and branch naming.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Poem

🐰 I sniffed the refs both near and far,
Resolved the SHA and set the branch ajar,
No guessing now where branches start,
A tidy worktree — straight from the heart! 🥕✨

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately describes the main fix: resolving --from ref to SHA to prevent git DWIM from overriding the branch name.
Linked Issues check	✅ Passed	The pull request fully addresses issue #146's objectives: resolves from_ref to commit SHA, prevents git DWIM override, ensures correct branch naming, maintains Git 2.17+ compatibility, and includes comprehensive tests.
Out of Scope Changes check	✅ Passed	All changes are directly scoped to fixing the identified issue—modifying core.sh to resolve refs and adding tests for the new behavior with no extraneous modifications.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.

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• Create PR with unit tests
• Post copyable unit tests in a comment

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[coderabbitai]

Actionable comments posted: 2

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Inline comments:
In `@lib/core.sh`:
- Around line 452-454: The current git rev-parse calls that set resolved_ref
from from_ref can return tag objects for annotated tags; change the rev-parse
invocations to peel to the commit by appending ^{commit} (e.g. git rev-parse
--verify "$from_ref^{commit}" 2>/dev/null and git rev-parse --verify
"origin/$from_ref^{commit}" 2>/dev/null) so resolved_ref is always a commit SHA,
and make the same change where from_ref is resolved/validated prior to git
worktree add (the other rev-parse usages around the git worktree add -b calls)
so worktree add receives a commit-ish not a tag object.

In `@tests/core_create_worktree.bats`:
- Around line 162-177: Add a new test variant that creates an annotated tag
(e.g., with git tag -a ... -m ...) and then calls the existing test flow that
uses create_worktree to ensure the worktree starts at the peeled commit ID;
specifically, duplicate the "create_worktree from tag starts at the tagged
commit" test but replace the lightweight tag creation (git tag v1.0.0) with an
annotated tag creation, verify expected_sha is the commit before creating the
annotated tag, call create_worktree the same way, and assert the worktree's HEAD
equals that commit so create_worktree (and the git rev-parse usage in
lib/core.sh) handles tag objects correctly.

---

ℹ️ Review info

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

Disabled knowledge base sources:

• Jira integration is disabled
• Linear integration is disabled

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📥 Commits

Reviewing files that changed from the base of the PR and between 0403d74 and 22d14d9.

📒 Files selected for processing (2)

• lib/core.sh
• tests/core_create_worktree.bats