remote: classify a remoteless repo as checkpoint-ref absence, not outage

[peyton-alt]

https://entire.io/gh/entireio/cli/trails/963

Main is currently red: TestRunExplainAuto_GeneratePersistsHexOnBranchUnderRefsPrimary fails on the tip (see #1885's test-core run — that PR only touches trail show, and the failure reproduces on pristine main with its diff stashed).

Root cause

A semantic conflict between the last two merges — each green alone:

• fix(checkpoint): kind-route backfill writes to the store holding the checkpoint #1811 routes backfill writes (e.g. explain --generate summary persistence) through the git-refs store.
• fix(checkpoint): fetch a locally-missing ref before declaring a backfill target absent #1824's on-demand fetch probes the remote when the local ref is missing, with the (correct) contract that transport failure is never mapped to absence.

In a fully local repository — no origin remote, no checkpoint_remote — the probe's origin-name fallback runs git ls-remote origin, gets exit 128 ('origin' does not appear to be a git repository), and the contract turns "this repo has no remotes" into a hard error. Backfill routing then fails instead of falling through to the branch store.

Fix

Before probing: if the fetch target is the non-authoritative origin fallback, no checkpoint_remote is configured, and origin has no URL, return the ref's absence (plumbing.ErrReferenceNotFound) — a repo with no remotes has no remote that could host checkpoint refs. Deliberately narrow:

• checkpoint_remote configured but unresolvable → unchanged (fallback emptiness still refuses to classify as absence)
• genuine transport failures → unchanged (still never absence)

New regression test TestFetchCheckpointRef_NoRemoteAtAllIsAbsence alongside the existing probe-contract tests, all green; the failing explain test passes with this fix.

🤖 Generated with Claude Code

---

Note

Low Risk
Small, scoped change to checkpoint ref fetch error classification with a regression test; does not relax transport-vs-absence rules for configured or reachable remotes.

Overview
Fixes backfill / explain --generate routing in fully local repos where on-demand checkpoint ref probing would hit the non-authoritative origin fallback and surface git ls-remote exit 128 as a transport error instead of “ref not found.”

FetchCheckpointRef adds a narrow pre-probe guard: when the target is the origin fallback, checkpoint_remote is not configured, and origin has no URL, it returns plumbing.ErrReferenceNotFound (wrapped) without calling ls-remote. Behavior is unchanged when checkpoint_remote is set (including unresolvable) or when a real remote exists but is unreachable.

Adds regression test TestFetchCheckpointRef_NoRemoteAtAllIsAbsence for a repo with no remotes.

^{Reviewed by Cursor Bugbot for commit 66c06c5. Configure here.}

[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

^{❌ Bugbot Autofix is OFF. To automatically fix reported issues with cloud agents, enable autofix in the Cursor dashboard.}

Comment @cursor review or bugbot run to trigger another review on this PR

^{Reviewed by Cursor Bugbot for commit 66c06c5. Configure here.}

[Copilot]

Pull request overview

This PR fixes a regression in checkpoint ref fetching for fully local Git repositories (no origin remote and no checkpoint_remote configured) by classifying the situation as “ref absent” instead of a transport outage, unblocking backfill flows like entire checkpoint explain --generate under git-refs primary.

Changes:

• Add a narrow pre-probe guard in FetchCheckpointRef to treat “no remotes at all” as plumbing.ErrReferenceNotFound rather than running git ls-remote origin and surfacing exit 128.
• Add a regression test covering the fully-local (no remotes) repo case.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
cmd/entire/cli/checkpoint/remote/checkpoint_ref.go	Adds a guard to classify remoteless repos as checkpoint-ref absence before probing/fetching.
cmd/entire/cli/checkpoint/remote/checkpoint_ref_test.go	Adds a regression test ensuring remoteless repos are treated as absence, not transport failure.