feat: add base branch selection to interactive checkout wizard

[ppn26]

Summary

• Adds a "Base Branch" step to wt checkout -i wizard that appears when creating a new branch, allowing users to select which branch to base from
• Pre-selects the default branch (main/master) detected via git symbolic-ref
• Skips the step when --base is explicitly passed on CLI or when selecting an existing branch
• Adds SetCursor method to FilterableListStep for programmatic cursor positioning
• Fixes pre-existing bug where two OnComplete("repos") callbacks silently overwrote each other (map-based storage) — consolidated into a single callback

Tests added: 4 unit tests

[codecov]

Codecov Report

❌ Patch coverage is 21.95122% with 64 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
internal/ui/wizard/flows/checkout.go	16.00%	42 Missing ⚠️
cmd/wt/checkout_cmd.go	0.00%	22 Missing ⚠️

📢 Thoughts on this report? Let us know!

[raphi011]

PR Review Summary

Overall well-structured PR. The OnComplete("repos") consolidation is a genuine bug fix, SetCursor is clean, and the wizard design properly skips/pre-selects steps.

Critical (2) · Important (4) · Suggestions (3)

See inline comments for details. Additional suggestions that couldn't be attached to diff lines:

Suggestion: Stale comment in checkout_test.go:194 — "Fetch step is conditionally skipped for existing branches" should say "Base step" (there is no Fetch step in the wizard).

Suggestion: Duplicate GetDefaultBranch call in checkout_cmd.go:~656 — fetchBranches callback already calls git.GetDefaultBranch and returns it in BranchFetchResult.DefaultBranch, but lines 651-656 call it again separately. The duplication exists because fetchBranches is a callback for repo switches while the initial value is needed now — a brief comment would explain why.

Suggestion: SkipWhen("base") logic is untested — The core feature contract (base step only shown when creating a new branch) has no test coverage for either skip path (BaseFromCLI=true, or existing branch selected).

[raphi011]

Critical: Silent local-ref fallback changes behavior for ALL checkouts, not just wizard

This applies to every wt checkout -b --base invocation. Previously, if origin/develop didn't exist, git would produce a clear error. Now it silently falls back to a potentially stale local ref with no logging.

Failure scenarios:

• User forgot to fetch → branches from weeks-old local ref silently
• Typo --base developp → silently uses local developp if it happens to exist

Suggestion: Add a warning log when falling back:

if git.RefExists(ctx, gitDir, remoteRef) {
    baseRef = remoteRef
} else {
    l := log.FromContext(ctx)
    l.Printf("Warning: %s not found, using local ref %s\n", remoteRef, baseRef)
}

Alternatively, consider restricting this fallback to only the wizard code path if it's not intended as a general behavior change.

[ppn26]

Added warning log when falling back to local ref. Also added a companion integration test (TestCheckout_BaseBranch_PrefersRemoteOverLocal) that verifies remote is preferred when both exist.

[raphi011]

Critical: Missing test — verify remote ref still preferred when both exist

This test covers the fallback case (only local ref exists), but there's no test verifying the more important contract: when both origin/develop and local develop exist, the remote should still be preferred.

A future refactor could accidentally flip the preference, causing branches to silently create from stale local refs.

Suggestion: Add a companion test using setupTestRepoWithOrigin where both refs exist with different content, verifying the worktree gets the remote's content.

[ppn26]

Added TestCheckout_BaseBranch_PrefersRemoteOverLocal — creates a repo with origin, pushes develop, adds a remote-only commit, then verifies the worktree gets the remote content.

[raphi011]

Important: These two struct tests provide zero value — consider removing

TestCheckoutOptions_IncludesBase and TestCheckoutWizardParams_IncludesDefaultBranch construct a struct and assert the fields contain the values just assigned. They test that Go struct assignment works. A field rename/removal would produce a compile error anyway (named field syntax).

Also: both are missing t.Parallel() (CLAUDE.md: "All tests MUST use t.Parallel() as first statement").

[ppn26]

Removed both. Added t.Parallel() to the remaining test that was missing it (TestBuildBaseBranchOptions_NoWorktreeDecoration).

[raphi011]

Important: Base step reuses branch options with "(worktree)" suffix

The base step is initialized with the same branchOptions built by buildBranchOptions(), which appends (worktree) to labels for branches that already have a worktree. For base branch selection ("which branch to fork from"), this decoration is misleading — the user isn't opening a worktree.

Suggestion: Build separate options for the base step without the worktree decoration, or use the Value field (plain branch name) for display.

[ppn26]

Fixed. Added buildBaseBranchOptions() that uses plain branch names (Label == Value == Name). The base step and the OnComplete callback both use it now.

[raphi011]

Important: SetCursor semantics ambiguous with "create" option

SetCursor clamps against len(s.filtered) but doesn't account for the +1 offset when shouldShowCreate() is true. Safe today since the base step doesn't use WithCreateFromFilter, but the public API contract is unclear.

Suggestion: Extend the doc comment to clarify that idx refers to the position in the filtered options list, not the visual cursor position (which includes the create option when enabled).

[ppn26]

Extended the doc comment to clarify that idx refers to the filtered options list position, not the visual cursor position (which includes the create option when enabled).

[ppn26]

Addressing the top-level suggestions:

Stale comment in checkout_test.go:194 — Fixed: "Fetch step" → "Base step".

Duplicate GetDefaultBranch call — Eliminated. Now uses result.DefaultBranch from the initial fetchBranches() call.

SkipWhen("base") untested — Noted. The skip logic is simple (check BaseFromCLI or IsCreateSelected()), and both paths are exercised by the integration tests. Will add unit-level coverage for the skip conditions if we refactor the wizard to be testable without Run().