.github/workflows/sync-labels.yml

@@ -0,0 +1,71 @@
+name: Sync labels to mirror
+
+# Labels do not travel with a mirror push -- mirroring copies files, not
+# repository settings -- but they matter on the GitHub side anyway, because
+# GitHub reads the same .github/ISSUE_TEMPLATE/ files and silently drops a
+# labels: entry naming a label it does not have. Gitea is the source of
+# truth; this makes the mirror match.
+
+on:
+  schedule:
+    # 06:00 UTC daily. Label churn is rare, so a slower cadence than this
+    # would leave the mirror wrong for most of a working day after an edit.
+    - cron: "0 6 * * *"
+  push:
+    branches:
+      - main
+    paths:
+      # Exercise the sync as soon as its own logic changes, rather than
+      # waiting for the next scheduled run to find out it is broken.
+      - "scripts/sync-labels.py"
+      - ".github/workflows/sync-labels.yml"
+  workflow_dispatch:
+    inputs:
+      dry_run:
+        description: "Report the plan without changing anything"
+        required: false
+        default: false
+        type: boolean
+
+jobs:
+  sync-labels:
+    # This file is mirrored to GitHub as-is. The runner label below only
+    # exists on the Gitea instance, so on GitHub the job would sit queued
+    # forever against a runner that will never pick it up -- the same
+    # problem the github-mirror stand-in in ci.yml exists to solve. A
+    # skipped job costs nothing and produces no stuck status.
+    if: github.server_url != 'https://github.com'
+    runs-on: racknerd-mini
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          token: ${{ secrets.GITEA_TOKEN }}
+
+      - name: Install Python
+        run: |
+          sudo apt-get -o Acquire::Retries=3 update -qq
+          sudo DEBIAN_FRONTEND=noninteractive apt-get install \
+            --no-install-recommends -y python3
+
+      # Cheap, offline, and no token needed. Catches a broken diff before
+      # anything is allowed to mutate labels on the mirror.
+      - name: Check the diff logic
+        run: python3 scripts/sync-labels.py --self-test
+
+      - name: Sync labels
+        env:
+          GH_MIRROR_TOKEN: ${{ secrets.GH_MIRROR_TOKEN }}
+        run: |
+          if [ -z "$GH_MIRROR_TOKEN" ]; then
+            echo "::error::GH_MIRROR_TOKEN is not set in this repository's Actions secrets."
+            echo "Create a fine-grained GitHub token scoped to rootiest/fish-config with"
+            echo "Issues: read and write, plus Pull requests: read, and add it as"
+            echo "GH_MIRROR_TOKEN under Settings -> Actions -> Secrets."
+            exit 1
+          fi
+          if [ "${{ inputs.dry_run }}" = "true" ]; then
+            python3 scripts/sync-labels.py --dry-run
+          else
+            python3 scripts/sync-labels.py
+          fi

scripts/sync-labels.py

@@ -0,0 +1,425 @@
+#!/usr/bin/env python3
+# Copyright (C) 2026 Rootiest
+# SPDX-License-Identifier: AGPL-3.0-or-later
+#
+# SYNOPSIS
+#   sync-labels.py [--dry-run] [--self-test]
+#
+# DESCRIPTION
+#   Syncs the label taxonomy from the canonical Gitea repo to the GitHub
+#   mirror. Gitea is the source of truth: labels are managed there, in the
+#   web UI or via its API, and this script makes GitHub match.
+#
+#   Mirroring copies files, not repository settings, so labels do not travel
+#   with a push. They matter on the mirror anyway, because GitHub reads the
+#   same .github/ISSUE_TEMPLATE/ files and silently drops a labels: entry
+#   naming a label that does not exist there.
+#
+#   Three actions, decided by comparing the two sets by label name:
+#
+#     missing on GitHub          created
+#     color or description drift updated
+#     extra on GitHub            deleted only if no issue or PR carries it,
+#                                otherwise left alone and reported
+#
+#   The usage check is what keeps an unattended scheduled run from stripping
+#   a label off somebody's issue. An extra label that is in use is reported
+#   with its count and requires a human decision.
+#
+# ARGUMENTS
+#   --dry-run    Print the plan and exit without changing anything. Works
+#                without a token, using GitHub's unauthenticated read quota.
+#   --self-test  Check the diff logic against in-memory fixtures and exit.
+#                Runs offline; makes no network calls.
+#
+# ENVIRONMENT
+#   GH_MIRROR_TOKEN  GitHub token with Issues: read and write (labels live
+#                    under Issues) and Pull requests: read (so the usage
+#                    check sees labels attached to PRs). Required unless
+#                    --dry-run or --self-test.
+#
+# EXIT STATUS
+#   0  Success, or a dry run that completed.
+#   1  An API call failed, the token is missing, or a self-test failed.
+#
+# NOTES
+#   Labels are matched by name, so renaming one on Gitea reads here as a
+#   delete plus a create: the new name is created, and the old one is pruned
+#   only if unused. The two forges share no stable label ID, so a rename
+#   cannot be tracked across them.
+#
+#   GitHub has no exclusive labels. Gitea's one-of enforcement on Priority/,
+#   Reviewed/, and Status/ does not survive the trip and holds by convention
+#   on the mirror.
+
+import argparse
+import json
+import os
+import sys
+import urllib.error
+import urllib.parse
+import urllib.request
+
+GITEA_API = "https://git.rootiest.dev/api/v1"
+GITEA_REPO = "Rootiest/fish-config"
+GITHUB_API = "https://api.github.com"
+GITHUB_REPO = "rootiest/fish-config"
+TOKEN_ENV = "GH_MIRROR_TOKEN"
+TIMEOUT = 30
+
+
+class SyncError(RuntimeError):
+    """An API call failed, or the environment is not usable."""
+
+
+# --------------------------------------------------------------------------
+# Pure diff core. No I/O lives below this line until the HTTP section, so
+# --self-test can exercise the decision logic offline.
+# --------------------------------------------------------------------------
+
+
+def normalize(label):
+    """Reduce a forge's label dict to (name, color, description).
+
+    Gitea returns colors bare ("00838f"), GitHub sometimes with a leading
+    "#", and either may use mixed case; a description may be null on GitHub
+    but "" on Gitea. Without this the two sets never compare equal and every
+    run would rewrite every label.
+    """
+    return (
+        label["name"],
+        (label.get("color") or "").lstrip("#").lower(),
+        label.get("description") or "",
+    )
+
+
+def plan(source, target):
+    """Compare two label lists and return the work to do.
+
+    Returns (to_create, to_update, extras): two lists of label dicts and a
+    list of names present on the target but not the source. Deciding whether
+    an extra is safe to delete needs the network, so that is left to the
+    caller.
+    """
+    src = {name: (color, desc) for name, color, desc in map(normalize, source)}
+    tgt = {name: (color, desc) for name, color, desc in map(normalize, target)}
+
+    to_create = [
+        {"name": name, "color": src[name][0], "description": src[name][1]}
+        for name in sorted(src.keys() - tgt.keys())
+    ]
+    to_update = [
+        {
+            "name": name,
+            "color": src[name][0],
+            "description": src[name][1],
+            "was": tgt[name],
+        }
+        for name in sorted(src.keys() & tgt.keys())
+        if src[name] != tgt[name]
+    ]
+    extras = sorted(tgt.keys() - src.keys())
+    return to_create, to_update, extras
+
+
+# --------------------------------------------------------------------------
+# HTTP
+# --------------------------------------------------------------------------
+
+
+def request(url, token=None, method="GET", payload=None):
+    body = json.dumps(payload).encode() if payload is not None else None
+    req = urllib.request.Request(url, data=body, method=method)
+    req.add_header("Accept", "application/json")
+    if body is not None:
+        req.add_header("Content-Type", "application/json")
+    if token:
+        req.add_header("Authorization", f"Bearer {token}")
+    try:
+        with urllib.request.urlopen(req, timeout=TIMEOUT) as response:
+            raw = response.read()
+            return json.loads(raw) if raw else None
+    except urllib.error.HTTPError as exc:
+        detail = exc.read().decode("utf-8", "replace")[:300]
+        raise SyncError(f"{method} {url} -> HTTP {exc.code}: {detail}") from None
+    except urllib.error.URLError as exc:
+        raise SyncError(f"{method} {url} -> {exc.reason}") from None
+
+
+def paginate(url_template, token=None, per_page=50):
+    """Collect every page of a list endpoint.
+
+    url_template takes {page} and {per_page}. Both forges stop returning
+    full pages at the end, which is the signal used here rather than trying
+    to parse differing Link headers.
+    """
+    collected = []
+    page = 1
+    while True:
+        batch = request(
+            url_template.format(page=page, per_page=per_page), token=token
+        )
+        if not batch:
+            break
+        collected.extend(batch)
+        if len(batch) < per_page:
+            break
+        page += 1
+    return collected
+
+
+def quoted(name):
+    """URL-encode a label name. Names carry '/', ' ', '&' and apostrophes."""
+    return urllib.parse.quote(name, safe="")
+
+
+def fetch_gitea_labels():
+    return paginate(
+        f"{GITEA_API}/repos/{GITEA_REPO}/labels?limit={{per_page}}&page={{page}}"
+    )
+
+
+def fetch_github_labels(token):
+    return paginate(
+        f"{GITHUB_API}/repos/{GITHUB_REPO}/labels?per_page={{per_page}}&page={{page}}",
+        token=token,
+    )
+
+
+def usage_count(name, token):
+    """How many issues or PRs on the mirror carry this label.
+
+    Caps at 100; the exact number past that does not change the decision,
+    which is only ever "zero" versus "not zero".
+    """
+    items = request(
+        f"{GITHUB_API}/repos/{GITHUB_REPO}/issues"
+        f"?labels={quoted(name)}&state=all&per_page=100",
+        token=token,
+    )
+    return len(items or [])
+
+
+def create_label(label, token):
+    request(
+        f"{GITHUB_API}/repos/{GITHUB_REPO}/labels",
+        token=token,
+        method="POST",
+        payload={
+            "name": label["name"],
+            "color": label["color"],
+            "description": label["description"],
+        },
+    )
+
+
+def update_label(label, token):
+    request(
+        f"{GITHUB_API}/repos/{GITHUB_REPO}/labels/{quoted(label['name'])}",
+        token=token,
+        method="PATCH",
+        payload={
+            "new_name": label["name"],
+            "color": label["color"],
+            "description": label["description"],
+        },
+    )
+
+
+def delete_label(name, token):
+    request(
+        f"{GITHUB_API}/repos/{GITHUB_REPO}/labels/{quoted(name)}",
+        token=token,
+        method="DELETE",
+    )
+
+
+# --------------------------------------------------------------------------
+# Reporting
+# --------------------------------------------------------------------------
+
+
+def emit_summary(lines):
+    """Append a run summary to the CI step summary, when running under CI."""
+    path = os.environ.get("GITHUB_STEP_SUMMARY")
+    if not path:
+        return
+    try:
+        with open(path, "a", encoding="utf-8") as handle:
+            handle.write("\n".join(lines) + "\n")
+    except OSError as exc:
+        print(f"note: could not write step summary: {exc}", file=sys.stderr)
+
+
+# --------------------------------------------------------------------------
+# Self-test
+# --------------------------------------------------------------------------
+
+
+def self_test():
+    checks = 0
+
+    def check(condition, message):
+        nonlocal checks
+        checks += 1
+        if not condition:
+            raise AssertionError(message)
+
+    # Identical sets produce no work. This is the case every scheduled run
+    # hits once the two forges agree, so it must be exactly empty rather
+    # than merely small.
+    same = [{"name": "Kind/Bug", "color": "ee0701", "description": "Broken"}]
+    create, update, extras = plan(same, list(same))
+    check(create == [] and update == [] and extras == [], "identical sets differ")
+
+    # Cosmetic representation differences are not drift. A "#" prefix,
+    # uppercase hex, and null-versus-empty description all appear in real
+    # API responses.
+    create, update, extras = plan(
+        [{"name": "A", "color": "00838F", "description": ""}],
+        [{"name": "A", "color": "#00838f", "description": None}],
+    )
+    check(update == [], "cosmetic color/description difference reported as drift")
+
+    # A real difference in either field is drift.
+    _, update, _ = plan(
+        [{"name": "A", "color": "111111", "description": "new"}],
+        [{"name": "A", "color": "222222", "description": "old"}],
+    )
+    check(len(update) == 1 and update[0]["color"] == "111111", "color drift missed")
+    _, update, _ = plan(
+        [{"name": "A", "color": "111111", "description": "new"}],
+        [{"name": "A", "color": "111111", "description": "old"}],
+    )
+    check(len(update) == 1, "description drift missed")
+
+    # Missing and extra are classified by direction, not lumped together.
+    create, update, extras = plan(
+        [{"name": "keep", "color": "1", "description": ""},
+         {"name": "add", "color": "2", "description": ""}],
+        [{"name": "keep", "color": "1", "description": ""},
+         {"name": "stale", "color": "3", "description": ""}],
+    )
+    check([c["name"] for c in create] == ["add"], "missing label not queued")
+    check(extras == ["stale"], "extra label not detected")
+    check(update == [], "unchanged label queued for update")
+
+    # An empty source must not be read as "delete everything silently" --
+    # extras still route through the caller's usage check.
+    create, update, extras = plan([], [{"name": "x", "color": "1", "description": ""}])
+    check(create == [] and update == [] and extras == ["x"], "empty source mishandled")
+
+    # Names that need URL encoding survive the round trip.
+    check(quoted("Area/Prompt & Theme") == "Area%2FPrompt%20%26%20Theme", "bad quoting")
+    check(quoted("Reviewed/Won't Fix") == "Reviewed%2FWon%27t%20Fix", "bad quoting")
+    checks += 2
+
+    # Output ordering is stable, so a run's log is diffable against the last.
+    create, _, extras = plan(
+        [{"name": "b", "color": "1", "description": ""},
+         {"name": "a", "color": "1", "description": ""}],
+        [{"name": "z", "color": "1", "description": ""},
+         {"name": "y", "color": "1", "description": ""}],
+    )
+    check([c["name"] for c in create] == ["a", "b"], "creates not sorted")
+    check(extras == ["y", "z"], "extras not sorted")
+
+    print(f"self-test: {checks} checks passed")
+    return 0
+
+
+# --------------------------------------------------------------------------
+# Entry point
+# --------------------------------------------------------------------------
+
+
+def run(dry_run):
+    token = os.environ.get(TOKEN_ENV)
+    if not token and not dry_run:
+        raise SyncError(
+            f"{TOKEN_ENV} is not set. Add a GitHub token to the Gitea repo's "
+            f"Actions secrets as {TOKEN_ENV}, with Issues: read and write "
+            "plus Pull requests: read, scoped to " + GITHUB_REPO + "."
+        )
+
+    source = fetch_gitea_labels()
+    if not source:
+        raise SyncError(
+            "Gitea returned no labels. Refusing to continue, since treating "
+            "that as the source of truth would propose deleting every label "
+            "on the mirror."
+        )
+    target = fetch_github_labels(token)
+    to_create, to_update, extras = plan(source, target)
+
+    prefix = "would " if dry_run else ""
+    log = [f"Gitea: {len(source)} labels    GitHub: {len(target)} labels", ""]
+
+    for label in to_create:
+        log.append(f"  {prefix}create  {label['name']}")
+        if not dry_run:
+            create_label(label, token)
+
+    for label in to_update:
+        old_color, old_desc = label["was"]
+        changed = []
+        if old_color != label["color"]:
+            changed.append(f"color {old_color} -> {label['color']}")
+        if old_desc != label["description"]:
+            changed.append("description")
+        log.append(f"  {prefix}update  {label['name']}  ({', '.join(changed)})")
+        if not dry_run:
+            update_label(label, token)
+
+    skipped = []
+    for name in extras:
+        count = usage_count(name, token)
+        if count:
+            skipped.append((name, count))
+            log.append(
+                f"  KEPT     {name}  (in use by {count} issue/PR"
+                f"{'s' if count != 1 else ''} -- delete by hand if intended)"
+            )
+        else:
+            log.append(f"  {prefix}delete  {name}  (unused)")
+            if not dry_run:
+                delete_label(name, token)
+
+    total = len(to_create) + len(to_update) + len(extras) - len(skipped)
+    if total == 0 and not skipped:
+        log.append("  no changes -- the mirror already matches Gitea")
+    log.append("")
+    log.append(
+        f"{'planned' if dry_run else 'applied'}: "
+        f"{len(to_create)} created, {len(to_update)} updated, "
+        f"{len(extras) - len(skipped)} deleted, {len(skipped)} kept in use"
+    )
+
+    print("\n".join(log))
+    emit_summary(["## Label sync", "", "```", *log, "```"])
+    return 0
+
+
+def main(argv=None):
+    parser = argparse.ArgumentParser(
+        description="Sync the label taxonomy from Gitea to the GitHub mirror."
+    )
+    parser.add_argument(
+        "--dry-run", action="store_true", help="print the plan, change nothing"
+    )
+    parser.add_argument(
+        "--self-test", action="store_true", help="check the diff logic offline"
+    )
+    args = parser.parse_args(argv)
+
+    if args.self_test:
+        return self_test()
+    try:
+        return run(args.dry_run)
+    except SyncError as exc:
+        print(f"error: {exc}", file=sys.stderr)
+        return 1
+
+
+if __name__ == "__main__":
+    sys.exit(main())