detect-upstream-base

name	detect-upstream-base
description	Detect the upstream vllm tag (v1) that the current branch is based on. Ensures the upstream remote is configured, fetches tags, and finds the nearest upstream tag reachable from the fork point. Use when you need to identify the upstream base version of the current branch, or when another skill needs v1 detection.

Detect Upstream Base Tag

Determine which upstream vllm tag the current branch is forked from.

Usage

Step 1: Ensure upstream remote

if ! git remote get-url upstream &>/dev/null; then
  git remote add upstream [e-mail]:vllm-project/vllm.git
fi
git fetch upstream --tags

Step 2: Detect v1

V1_BASE=$(git merge-base HEAD upstream/main)
V1=$(git describe --tags --abbrev=0 --match="v*" "$V1_BASE" 2>/dev/null)

If git describe fails (no reachable tag), fall back to the merge-base SHA:

V1=${V1:-$V1_BASE}

Step 3: Confirm with user

Present to user: "The current upstream base tag appears to be $V1. Is this correct, or would you like to specify a different tag?"

Wait for explicit confirmation before returning the value.

Output

The confirmed value of V1 (an upstream tag like v0.19.1 or a commit SHA).