[peyton-alt]

https://entire.com/gh/entireio/-/trails/2514/changes/cli/1677

Problem

With no --base, entire trail create used the clone's origin/HEAD, and when the clone had none (origin added or re-pointed by hand, older git) it guessed main whenever origin/main existed. It sent that guess, so the server never applied the repo's real default branch (trail.base || repo.default_branch).

In a repo whose default isn't main:

• the trail gets base main, Entire's draft targets main, and the user's own PR into the real default can't settle the trail (merge matching needs the same base) — it stays open and the draft keeps re-running CI. This is the root cause behind a customer report of a duplicate draft on already-merged work (entire-api trail 1094 guards a different path to the same symptom).
• when the user is on the default branch, the wrong guess also makes the trail reuse the default branch itself, so the draft proposes merging the whole default branch into main.

Fix

Base = --base, else origin/HEAD, else origin's HEAD from git ls-remote --symref origin HEAD (10s bound, non-interactive, output parsed strictly and validated as a branch name), else nothing — the server then uses the repo's default branch. Both create paths (repo trails and project trails) use it. Branch naming keeps the old local main/master guess when the base is unknown; that guess is never sent.

The lookup is a package seam stubbed to "unknown" in TestMain, so no unit test reaches a real remote.

Evidence (live, real entire trail create)

Throwaway GitHub repo with default branch release, clone without origin/HEAD, on release:

	installed nightly	this branch
trail base	main	release
trail branch	release (the default itself)	base-fix-new-binary (from the title)
Entire's draft	release → main	base-fix-new-binary → release
after merging the PR	—	trail merged

git ls-remote --symref origin HEAD also verified against a private GitHub remote (release) and an entire:// remote (main).

Notes / follow-ups

• A stale local origin/HEAD (default renamed after clone) still wins over the server, as before.
• Other GetDefaultBranchName users (explain, import, resume) keep the old guess; out of scope (see ENT-129 duplication).
• If the lookup fails and the user is on a non-main default with a title, naming may reuse the current branch and the server rejects it ("branch is base"); pass --branch or --base.

Testing

• Unit: symref parsing, a local bare remote whose HEAD is release, unreachable remote, base selection (explicit / origin/HEAD / remote / unknown / invalid), and the project create payload omitting an unknown base.
• mise run check passes (the claudecode timing test failed only under machine load and passes on rerun).

🤖 Generated with Claude Code

---

Note

Medium Risk
Changes default trail base sent to the API and branch naming inputs for trail create; wrong behavior could mis-target drafts or branches, but logic is bounded, validated, and well-tested.

Overview
Trail create no longer sends a guessed main as the API base when --base is omitted and the real default branch cannot be determined confidently.

Resolution is split into what goes to the server vs what drives branch naming. The sent base is --base, else local origin/HEAD, else git ls-remote --symref (10s timeout, strict parsing, branch-name validation), else empty so the server applies the repo default. The old local main/master guess is kept only for namingBase (e.g. resolveCreateBranch) and is never posted.

resolveTrailCreateBase moves to trail_base.go; entire trail create and project trail publish both use it. Package tests stub remote lookup in TestMain; new unit tests cover symref parsing, remote HEAD, and base-selection cases; project create tests expect an omitted base when lookup is unknown.

^{Reviewed by Cursor Bugbot for commit 6bd3aeb. Configure here.}

[Copilot]

🟡 Changes recommended

Unchecked local symref targets can still produce incorrect trail bases, and subprocess output capture remains unbounded.

2 open issues

• Handle missing remote prefix instead of using the full ref · New
• Limit stdout and stderr while capturing command output · New

What changed in this PR

This PR separates trail base selection from branch naming so trail creation no longer sends a guessed main that overrides the server’s repository default.

Changes:

• Resolve the base from --base, local origin/HEAD, or a bounded remote lookup; otherwise omit it.
• Apply the shared resolver to repository and project trails, keeping local guesses only for branch naming.
• Add resolver tests and stub remote lookup in package tests.

File	Description
cmd/​entire/​cli/​trail_cmd.go	Separates the API base from branch-naming input.
cmd/​entire/​cli/​trail_base.go	Adds shared local and remote default-branch resolution.
cmd/​entire/​cli/​trail_base_test.go	Tests parsing, remote lookup, and base-selection precedence.
cmd/​entire/​cli/​project_trail_publish.go	Applies separate base and naming values to project trails.
cmd/​entire/​cli/​project_trail_publish_test.go	Expects an omitted base when detection is inconclusive.
cmd/​entire/​cli/​global_test.go	Stubs remote default-branch lookup for package tests.

_{Review effort: Balanced}