CI: add PR labeler + label sync

scripts/sync-labels.ts

@@ -0,0 +1,91 @@
+import { execFileSync } from "node:child_process";
+import { readFileSync } from "node:fs";
+import { resolve } from "node:path";
+import yaml from "yaml";
+
+type LabelConfig = Record<string, unknown>;
+
+type RepoLabel = {
+  name: string;
+  color?: string;
+};
+
+const COLOR_BY_PREFIX = new Map<string, string>([
+  ["channel", "1d76db"],
+  ["app", "6f42c1"],
+  ["extensions", "0e8a16"],
+  ["docs", "0075ca"],
+  ["cli", "f9d0c4"],
+  ["gateway", "d4c5f9"],
+]);
+
+const configPath = resolve(".github/labeler.yml");
+const config = yaml.parse(readFileSync(configPath, "utf8")) as LabelConfig;
+
+if (!config || typeof config !== "object") {
+  throw new Error("labeler.yml must be a mapping of label names to globs.");
+}
+
+const labelNames = Object.keys(config).filter(Boolean);
+const repo = resolveRepo();
+const existing = fetchExistingLabels(repo);
+
+const missing = labelNames.filter((label) => !existing.has(label));
+if (!missing.length) {
+  console.log("All labeler labels already exist.");
+  process.exit(0);
+}
+
+for (const label of missing) {
+  const color = pickColor(label);
+  execFileSync(
+    "gh",
+    [
+      "api",
+      "-X",
+      "POST",
+      `repos/${repo}/labels`,
+      "-f",
+      `name=${label}`,
+      "-f",
+      `color=${color}`,
+    ],
+    { stdio: "inherit" },
+  );
+  console.log(`Created label: ${label}`);
+}
+
+function pickColor(label: string): string {
+  const prefix = label.includes(":") ? label.split(":", 1)[0].trim() : label.trim();
+  return COLOR_BY_PREFIX.get(prefix) ?? "ededed";
+}
+
+function resolveRepo(): string {
+  const remote = execFileSync("git", ["config", "--get", "remote.origin.url"], {
+    encoding: "utf8",
+  }).trim();
+
+  if (!remote) {
+    throw new Error("Unable to determine repository from git remote.");
+  }
+
+  if (remote.startsWith("git@github.com:")) {
+    return remote.replace("git@github.com:", "").replace(/\.git$/, "");
+  }
+
+  if (remote.startsWith("https://github.com/")) {
+    return remote.replace("https://github.com/", "").replace(/\.git$/, "");
+  }
+
+  throw new Error(`Unsupported GitHub remote: ${remote}`);
+}
+
+function fetchExistingLabels(repo: string): Map<string, RepoLabel> {
+  const raw = execFileSync(
+    "gh",
+    ["api", `repos/${repo}/labels?per_page=100`, "--paginate"],
+    { encoding: "utf8" },
+  );
+  const labels = JSON.parse(raw) as RepoLabel[];
+  return new Map(labels.map((label) => [label.name, label]));
+}