sglang-cherrypick

name	sglang-cherrypick
description	Trigger the bot-cherry-pick workflow for a batch of merged PRs onto a release branch and monitor each run to completion. Use when an SGLang release manager asks to cherry-pick a list of PRs to a release branch.

SGLang Cherry-Pick

Trigger .github/workflows/bot-cherry-pick.yml for each PR in a list, then monitor the resulting workflow runs and report per-PR success/failure with links to the created cherry-pick PRs (or the failure reason).

Slash Command

/sglang-cherrypick <target_branch> <pr1> [pr2 pr3 ...]

Examples:

• /sglang-cherrypick release/v0.5.7 25956 25958 25987
• /sglang-cherrypick release/v0.5.7 25956,25958,25987 (comma-separated also accepted)

Arguments

• target_branch (required): Release branch in the form release/vX.Y or release/vX.Y.Z. Must already exist on origin (i.e., sgl-project/sglang).
• pr_numbers (required, one or more): Merged PR numbers to cherry-pick. Each must be a positive integer.

Repository

Always targets the upstream repo sgl-project/sglang. The workflow's job guard (if: github.repository == 'sgl-project/sglang') means triggering it on a fork is a no-op.

Workflow

Step 1 — Validate arguments

Fail fast before triggering anything.

# target branch shape (matches the workflow's own validator)
[[ "$TARGET_BRANCH" =~ ^release/v[0-9]+\.[0-9]+(\.[0-9]+)?$ ]] || die "Invalid target_branch"

# branch exists on upstream
gh api "repos/sgl-project/sglang/branches/$TARGET_BRANCH" --jq '.name' >/dev/null || die "Branch not found"

# each PR is numeric, exists, MERGED, and has a recorded merge commit
declare -A PR_TO_SHA=()
declare -A PR_TO_TITLE=()
for PR in "${PRS[@]}"; do
  [[ "$PR" =~ ^[0-9]+$ ]] || die "PR '$PR' is not a positive integer"
  PR_JSON=$(gh pr view "$PR" --repo sgl-project/sglang --json state,mergeCommit,title) \
    || die "PR #$PR not found"
  STATE=$(jq -r .state <<<"$PR_JSON")
  [[ "$STATE" == "MERGED" ]] || die "PR #$PR is not MERGED (state=$STATE)"
  SHA=$(jq -r '.mergeCommit.oid // empty' <<<"$PR_JSON")
  [[ -n "$SHA" ]] || die "PR #$PR has no merge commit recorded"
  PR_TO_SHA[$PR]="$SHA"
  PR_TO_TITLE[$PR]=$(jq -r .title <<<"$PR_JSON")
done

Report any failures and stop — do not trigger partial batches.

Step 2 — Pre-flight: list changed files and detect conflicts locally

Before dispatching any workflow, simulate each cherry-pick locally with git merge-tree to (a) show the user which files would change and (b) catch conflicts before paying for a CI run. git merge-tree --write-tree is a side-effect-free 3-way merge — it touches neither the working tree nor any ref.

2a. Locate the upstream remote (sgl-project/sglang). Both the dual-remote (upstream + origin fork) and single-remote setups need to work.

UPSTREAM_REMOTE=$(git remote -v \
  | awk '$2 ~ /[:\/]sgl-project\/sglang(\.git)?$/ && $3 == "(fetch)" {print $1; exit}')
[[ -n "$UPSTREAM_REMOTE" ]] || die "No remote points to sgl-project/sglang"

2b. Fetch the target branch and each PR's merge commit. Fetch the commits by SHA (in case they're not on a ref the user has locally) and the target branch in one call.

git fetch "$UPSTREAM_REMOTE" "$TARGET_BRANCH" "${PR_TO_SHA[@]}" --quiet \
  || die "Failed to fetch from $UPSTREAM_REMOTE"

TARGET_REF="refs/remotes/$UPSTREAM_REMOTE/$TARGET_BRANCH"

2c. Index existing cherry-pick PRs on the target branch. One gh pr list call gets every cherry-pick PR ever filed against this branch (any state). For each input PR, we cross-reference by the title suffix (#<PR>) that the bot workflow always uses.

# Fetch all cherry-pick PRs against this branch (any state), then bucket by
# source-PR number using the title pattern "(#<source_pr>)".
EXISTING_CP_JSON=$(gh pr list --repo sgl-project/sglang \
  --base "$TARGET_BRANCH" \
  --label cherry-pick \
  --state all \
  --limit 200 \
  --json number,title,url,state)

declare -A PR_TO_EXISTING_CP=()   # source_pr -> JSON array of existing cherry-pick PRs
for PR in "${PRS[@]}"; do
  PR_TO_EXISTING_CP[$PR]=$(jq -c \
    "[.[] | select(.title | contains(\"(#${PR})\"))]" <<<"$EXISTING_CP_JSON")
done

For each input PR, classify the existing cherry-picks:

• MERGED present → the cherry-pick already landed. Skip this PR in Step 3.
• OPEN present (and no MERGED) → a previous dispatch is still in flight. Warn, ask the user whether to skip or re-dispatch, but default to skip (re-dispatching creates a duplicate).
• Only CLOSED (no merged, no open) → previous attempts were abandoned; safe to re-dispatch.
• Empty → no prior attempt; proceed normally.

2d. For each PR, run git merge-tree and diff the result. The semantics of cherry-pick are: 3-way-merge with base = parent of source commit, ours = target tip, theirs = source commit. For merge commits the workflow uses -m 1, which means base = first parent — ${SHA}^ resolves to ${SHA}^1 for both regular and merge commits, so one form covers both.

declare -A PR_TO_CONFLICTS=()
declare -A PR_TO_FILES=()

for PR in "${PRS[@]}"; do
  SHA="${PR_TO_SHA[$PR]}"

  # --write-tree: print the resulting tree SHA on success
  # Exit 0 = clean merge; exit 1 = conflicts
  if MERGE_OUT=$(git merge-tree --write-tree \
                   --merge-base="${SHA}^" \
                   "$TARGET_REF" "$SHA" 2>&1); then
    RESULT_TREE=$(head -1 <<<"$MERGE_OUT")
    PR_TO_CONFLICTS[$PR]=""
    # Show files that actually differ between target tip and the merged tree.
    # This is more accurate than `git show --name-status $SHA` because it
    # accounts for changes already present on the release branch. As a
    # side-effect, an already-cherry-picked commit shows up here as "0 files".
    PR_TO_FILES[$PR]=$(git diff --name-status "$TARGET_REF" "$RESULT_TREE")
  else
    # Conflict output format (git ≥2.40): first line is the (partial) tree,
    # remaining lines list conflicted paths and informational messages.
    # We just capture and surface it; user decides what to do.
    PR_TO_CONFLICTS[$PR]="$MERGE_OUT"
    PR_TO_FILES[$PR]=$(git show --name-status --format= "$SHA" 2>/dev/null)
  fi
done

2e. Print a pre-flight report. One table summarizing each PR, followed by per-PR file lists. The "Prior cherry-pick" column uses the classification from 2c.

## Cherry-Pick Pre-Flight — `release/vX.Y.Z`

| PR     | Title                    | Merge SHA | Prior cherry-pick    | Conflicts    | # files |
|--------|--------------------------|-----------|----------------------|--------------|---------|
| #25733 | [Bug] Fix V4-Pro NaN ... | 79ea30d1  | ✅ merged as #26063  | clean        | 0       |
| #25562 | [bugfix] Fix wrong ...   | b19052c9  | none                 | **CONFLICT** | —       |
| #25585 | [Bugfix] Fix missing ... | 86c6c77f  | none                 | clean        | 2       |

### Files (PR #25585 — clean)
M  python/sglang/srt/layers/communicator.py
M  python/sglang/srt/models/deepseek_v4.py

### Conflict detail (PR #25562)
<merge-tree output: conflicted paths and reasons>

2f. Gate before dispatching. Stop and report if any PR is in either of these states:

• git merge-tree reports a conflict — the workflow would just fail; let the user fix or remove that PR.
• Already has a MERGED cherry-pick PR on the target branch — re-dispatching would create a redundant PR. Skip it (or, if the user really wants a re-run, they can pass an explicit override list).
• Has an OPEN cherry-pick PR with no merged one — default to skipping with a warning; surface the open PR's URL so the user can review/merge/close it before re-dispatching.

Only PRs that are clean AND have no merged-or-open prior cherry-pick should proceed to Step 3.

As a sanity check, a clean pre-flight that shows 0 files changed is the structural signature of "this commit is already on the branch" — if you see it without an existing merged cherry-pick PR being detected (rare, e.g. the original PR was force-merged onto the release branch directly), surface that too and skip the dispatch.

Step 3 — Dispatch each PR's workflow run

gh workflow run (gh ≥2.45) prints the dispatched run's URL on stdout — parse it directly. Fall back to the snapshot/diff polling only if the URL isn't returned (older gh).

# Snapshot once up front in case we need the fallback path.
mapfile -t SEEN < <(gh run list \
  --workflow=bot-cherry-pick.yml \
  --repo sgl-project/sglang \
  --limit 50 \
  --json databaseId --jq '.[].databaseId')

declare -A PR_TO_RUN=()  # pr_number -> run_id

for PR in "${PRS[@]}"; do
  DISPATCH_OUT=$(gh workflow run bot-cherry-pick.yml \
    --repo sgl-project/sglang \
    -f pr_number="$PR" \
    -f target_branch="$TARGET_BRANCH" 2>&1) || { echo "$DISPATCH_OUT"; die "dispatch failed for PR #$PR"; }

  # Preferred path: gh prints the run URL like
  #   https://github.com/sgl-project/sglang/actions/runs/26275460359
  RUN_URL=$(grep -oE 'https://github.com/[^[:space:]]+/actions/runs/[0-9]+' \
              <<<"$DISPATCH_OUT" | head -1)
  RUN_ID="${RUN_URL##*/}"

  # Fallback for older gh that doesn't print the URL: poll the runs list,
  # filter to workflow_dispatch events we haven't seen yet.
  if [[ -z "$RUN_ID" ]]; then
    for _ in $(seq 1 30); do
      sleep 2
      CANDIDATE=$(gh run list \
        --workflow=bot-cherry-pick.yml \
        --repo sgl-project/sglang \
        --limit 10 \
        --json databaseId,event \
        --jq '[.[] | select(.event=="workflow_dispatch") | .databaseId] | .[0]')
      if [[ -n "$CANDIDATE" ]] \
         && ! printf '%s\n' "${SEEN[@]}" | grep -qx "$CANDIDATE" \
         && ! printf '%s\n' "${PR_TO_RUN[@]}" | grep -qx "$CANDIDATE"; then
        RUN_ID="$CANDIDATE"
        break
      fi
    done
  fi

  if [[ -z "$RUN_ID" ]]; then
    echo "::warning::No new workflow run detected for PR #$PR within 60s"
    PR_TO_RUN[$PR]="UNKNOWN"
  else
    PR_TO_RUN[$PR]="$RUN_ID"
  fi
done

Notes:

• The workflow has concurrency: cherry-pick-${{ target_branch }} with cancel-in-progress: false. So multiple dispatches against the same target branch queue serially, not in parallel. That's fine — we batch the triggers and the GitHub side serializes execution.
• gh workflow run is fire-and-forget; the dispatched run shows up in gh run list within a few seconds.

Step 4 — Monitor each run to completion

Use gh run watch per run id, sequentially (since they execute serially anyway).

for PR in "${PRS[@]}"; do
  RUN_ID="${PR_TO_RUN[$PR]}"
  [[ "$RUN_ID" == "UNKNOWN" ]] && continue

  gh run watch "$RUN_ID" \
    --repo sgl-project/sglang \
    --exit-status \
    --interval 15 \
    >/dev/null 2>&1 || true   # we read conclusion below; don't abort the loop on fail
done

gh run watch blocks until the run completes. Use --interval 15 to be polite on rate limits.

Step 5 — Collect outcomes per PR

For each PR, fetch the run conclusion and (if successful) the URL of the created cherry-pick PR.

for PR in "${PRS[@]}"; do
  RUN_ID="${PR_TO_RUN[$PR]}"

  if [[ "$RUN_ID" == "UNKNOWN" ]]; then
    echo "PR #$PR: UNKNOWN (no run found)"
    continue
  fi

  CONCLUSION=$(gh run view "$RUN_ID" --repo sgl-project/sglang \
    --json conclusion,status,url \
    --jq '"\(.status) \(.conclusion) \(.url)"')

  STATUS=$(awk '{print $1}' <<<"$CONCLUSION")
  RESULT=$(awk '{print $2}' <<<"$CONCLUSION")
  RUN_URL=$(awk '{print $3}' <<<"$CONCLUSION")

  if [[ "$RESULT" == "success" ]]; then
    # Find the cherry-pick PR created by this run. Title format from the workflow:
    #   "[Cherry-pick to <BRANCH>] <ORIG TITLE> (#<PR>)"
    CP_PR=$(gh pr list --repo sgl-project/sglang \
      --base "$TARGET_BRANCH" \
      --label cherry-pick \
      --state all \
      --limit 30 \
      --json number,title,url,createdAt \
      --jq "[.[] | select(.title | contains(\"(#${PR})\"))][0]")

    CP_URL=$(jq -r '.url // "N/A"' <<<"$CP_PR")
    CP_NUM=$(jq -r '.number // "?"' <<<"$CP_PR")
    echo "PR #$PR  -> SUCCESS  cherry-pick PR #$CP_NUM ($CP_URL)  [run: $RUN_URL]"
  else
    # Failure: pull the cherry-pick step's last error line so the user sees why.
    REASON=$(gh run view "$RUN_ID" --repo sgl-project/sglang --log-failed 2>/dev/null \
      | grep -m1 -E "::error::" \
      | sed -E 's/^[^:]*::error::?//' \
      || echo "(see run logs)")
    echo "PR #$PR  -> $RESULT  reason: $REASON  [run: $RUN_URL]"
  fi
done

Step 6 — Final summary

Print one table sorted by input order:

## Cherry-Pick Batch Summary — `release/v0.5.7`

| PR  | Status   | Cherry-pick PR | Run | Notes |
|-----|----------|----------------|-----|-------|
| #25956 | success | #26031 | run/12345 | — |
| #25958 | failure | —      | run/12346 | Cherry-pick of <SHA> onto release/v0.5.7 failed due to conflicts |
| #25987 | success | #26032 | run/12347 | — |

**Totals:** N succeeded, M failed, K unknown.

For any failure, suggest the manual fallback from the workflow's own error message:

Resolve locally: git checkout release/v0.5.7 && git cherry-pick <SHA>, fix conflicts, push a branch, and open the PR by hand.

Common Failure Modes

Symptom	Cause	Action
PR #X is not merged (state=OPEN)	PR not yet merged	Wait for merge or pass --commit-sha (not supported by this slash command)
Target branch '...' does not exist	Typo or branch not cut yet	Confirm branch name; release manager may not have cut it
Cherry-pick of <SHA> onto <BRANCH> failed due to conflicts	Code drift on release branch (should already have been caught in Step 2 pre-flight)	Do it manually as instructed above
Pre-flight git merge-tree reports a conflict	Same as above, caught locally before any CI run	Remove that PR from the batch and resolve manually
No remote points to sgl-project/sglang	Skill invoked from a checkout that only has a fork remote	Add the upstream remote: git remote add upstream https://github.com/sgl-project/sglang.git
Pre-flight git merge-tree errors with unknown option	git < 2.38	Upgrade git, or run the skill on a machine with a modern git
Pre-flight reports Prior cherry-pick: merged as #N	The PR has already been cherry-picked and merged onto this release branch	Skip this PR — re-dispatching would create a duplicate PR. Verify #N is the right one before removing from the list.
Pre-flight reports Prior cherry-pick: OPEN as #N	A previous dispatch is still in flight (PR not yet merged or closed)	Default: skip and ask the user to land or close #N first. Re-dispatching creates a parallel duplicate that needs to be cleaned up afterwards.
Pre-flight is clean but # files = 0 and no prior cherry-pick PR was found	Commit landed on the release branch by direct merge (not via the bot), or via a rebase that rewrote the SHA	Skip the dispatch — the change is already there. Surface this anomaly so the user knows the bot wasn't the source.
Multiple runs but only one detected	Two dispatches landed in the same gh run list poll cycle	Re-run for the missing PR, or look up its run by hand: gh run list --workflow=bot-cherry-pick.yml --event workflow_dispatch -L 20
403 on gh workflow run	Missing actions:write on the token	Use a token that has workflow dispatch rights on sgl-project/sglang

Notes

• The skill never modifies the workflow file. It only dispatches it.
• The skill operates on the upstream repo only (sgl-project/sglang); the user's fork is irrelevant here.
• Per-branch concurrency means picking 20 PRs to the same release branch will take ~20× the runtime of one. There is no parallelism to be gained client-side. If the user batches across different target branches, those run concurrently.
• Do not skip the merged-state precheck — the workflow will reject unmerged PRs, but we want a single batched validation report up front rather than N individual workflow failures.
• The skill should be invoked with gh auth status already passing; if not, surface the auth error and stop.