ci: consolidate PR labeling into unified workflows (#36042)

Consolidate four separate PR labeling workflows (`pr_labeler_file.yml`,
`pr_labeler_title.yml`, `pr_size_labeler.yml`, and the PR-handling half
of `tag-external-contributions.yml`) into a single `pr_labeler.yml`
workflow. The old workflows raced against each other — concurrent label
mutations could drop or duplicate labels depending on execution order. A
unified workflow with concurrency grouping eliminates that class of bug.

.github/scripts/pr-labeler-config.json

@@ -0,0 +1,84 @@
+{
+  "trustedThreshold": 5,
+  "labelColor": "b76e79",
+  "sizeThresholds": [
+    { "label": "size: XS", "max": 50 },
+    { "label": "size: S", "max": 200 },
+    { "label": "size: M", "max": 500 },
+    { "label": "size: L", "max": 1000 },
+    { "label": "size: XL" }
+  ],
+  "excludedFiles": ["uv.lock"],
+  "excludedPaths": ["docs/"],
+  "typeToLabel": {
+    "feat": "feature",
+    "fix": "fix",
+    "docs": "documentation",
+    "style": "linting",
+    "refactor": "refactor",
+    "perf": "performance",
+    "test": "tests",
+    "build": "infra",
+    "ci": "infra",
+    "chore": "infra",
+    "revert": "revert",
+    "release": "release",
+    "hotfix": "hotfix",
+    "breaking": "breaking"
+  },
+  "scopeToLabel": {
+    "core": "core",
+    "langchain": "langchain",
+    "langchain-classic": "langchain-classic",
+    "model-profiles": "model-profiles",
+    "standard-tests": "standard-tests",
+    "text-splitters": "text-splitters",
+    "anthropic": "anthropic",
+    "chroma": "chroma",
+    "deepseek": "deepseek",
+    "exa": "exa",
+    "fireworks": "fireworks",
+    "groq": "groq",
+    "huggingface": "huggingface",
+    "mistralai": "mistralai",
+    "nomic": "nomic",
+    "ollama": "ollama",
+    "openai": "openai",
+    "openrouter": "openrouter",
+    "perplexity": "perplexity",
+    "qdrant": "qdrant",
+    "xai": "xai",
+    "deps": "dependencies",
+    "docs": "documentation",
+    "infra": "infra"
+  },
+  "fileRules": [
+    { "label": "core", "prefix": "libs/core/" },
+    { "label": "langchain-classic", "prefix": "libs/langchain/" },
+    { "label": "langchain", "prefix": "libs/langchain_v1/" },
+    { "label": "standard-tests", "prefix": "libs/standard-tests/" },
+    { "label": "model-profiles", "prefix": "libs/model-profiles/" },
+    { "label": "text-splitters", "prefix": "libs/text-splitters/" },
+    { "label": "integration", "prefix": "libs/partners/" },
+    { "label": "anthropic", "prefix": "libs/partners/anthropic/" },
+    { "label": "chroma", "prefix": "libs/partners/chroma/" },
+    { "label": "deepseek", "prefix": "libs/partners/deepseek/" },
+    { "label": "exa", "prefix": "libs/partners/exa/" },
+    { "label": "fireworks", "prefix": "libs/partners/fireworks/" },
+    { "label": "groq", "prefix": "libs/partners/groq/" },
+    { "label": "huggingface", "prefix": "libs/partners/huggingface/" },
+    { "label": "mistralai", "prefix": "libs/partners/mistralai/" },
+    { "label": "nomic", "prefix": "libs/partners/nomic/" },
+    { "label": "ollama", "prefix": "libs/partners/ollama/" },
+    { "label": "openai", "prefix": "libs/partners/openai/" },
+    { "label": "openrouter", "prefix": "libs/partners/openrouter/" },
+    { "label": "perplexity", "prefix": "libs/partners/perplexity/" },
+    { "label": "qdrant", "prefix": "libs/partners/qdrant/" },
+    { "label": "xai", "prefix": "libs/partners/xai/" },
+    { "label": "github_actions", "prefix": ".github/workflows/" },
+    { "label": "github_actions", "prefix": ".github/actions/" },
+    { "label": "dependencies", "suffix": "pyproject.toml" },
+    { "label": "dependencies", "exact": "uv.lock" },
+    { "label": "dependencies", "pattern": "(?:^|/)requirements[^/]*\\.txt$" }
+  ]
+}

.github/scripts/pr-labeler.js

@@ -0,0 +1,271 @@
+// Shared helpers for pr_labeler.yml and tag-external-issues.yml.
+//
+// Usage from actions/github-script (requires actions/checkout first):
+//   const { h } = require('./.github/scripts/pr-labeler.js').loadAndInit(github, owner, repo);
+
+const fs = require('fs');
+const path = require('path');
+
+function loadConfig() {
+  const configPath = path.join(__dirname, 'pr-labeler-config.json');
+  let raw;
+  try {
+    raw = fs.readFileSync(configPath, 'utf8');
+  } catch (e) {
+    throw new Error(`Failed to read ${configPath}: ${e.message}`);
+  }
+  let config;
+  try {
+    config = JSON.parse(raw);
+  } catch (e) {
+    throw new Error(`Failed to parse pr-labeler-config.json: ${e.message}`);
+  }
+  const required = [
+    'labelColor', 'sizeThresholds', 'fileRules',
+    'typeToLabel', 'scopeToLabel', 'trustedThreshold',
+    'excludedFiles', 'excludedPaths',
+  ];
+  const missing = required.filter(k => !(k in config));
+  if (missing.length > 0) {
+    throw new Error(`pr-labeler-config.json missing required keys: ${missing.join(', ')}`);
+  }
+  return config;
+}
+
+function init(github, owner, repo, config) {
+  const {
+    trustedThreshold,
+    labelColor,
+    sizeThresholds,
+    scopeToLabel,
+    typeToLabel,
+    fileRules: fileRulesDef,
+    excludedFiles,
+    excludedPaths,
+  } = config;
+
+  const sizeLabels = sizeThresholds.map(t => t.label);
+  const allTypeLabels = [...new Set(Object.values(typeToLabel))];
+  const tierLabels = ['new-contributor', 'trusted-contributor'];
+
+  // ── Label management ──────────────────────────────────────────────
+
+  async function ensureLabel(name, color = labelColor) {
+    try {
+      await github.rest.issues.getLabel({ owner, repo, name });
+    } catch (e) {
+      if (e.status !== 404) throw e;
+      try {
+        await github.rest.issues.createLabel({ owner, repo, name, color });
+      } catch (createErr) {
+        // 422 = label created by a concurrent run between our get and create
+        if (createErr.status !== 422) throw createErr;
+        const core = require('@actions/core');
+        core.info(`Label "${name}" creation returned 422 (likely already exists)`);
+      }
+    }
+  }
+
+  // ── Size calculation ──────────────────────────────────────────────
+
+  function getSizeLabel(totalChanged) {
+    for (const t of sizeThresholds) {
+      if (t.max != null && totalChanged < t.max) return t.label;
+    }
+    // Last entry has no max — it's the catch-all
+    return sizeThresholds[sizeThresholds.length - 1].label;
+  }
+
+  function computeSize(files) {
+    const excluded = new Set(excludedFiles);
+    const totalChanged = files.reduce((sum, f) => {
+      const p = f.filename ?? '';
+      const base = p.split('/').pop();
+      if (excluded.has(base)) return sum;
+      for (const prefix of excludedPaths) {
+        if (p.startsWith(prefix)) return sum;
+      }
+      return sum + (f.additions ?? 0) + (f.deletions ?? 0);
+    }, 0);
+    return { totalChanged, sizeLabel: getSizeLabel(totalChanged) };
+  }
+
+  // ── File-based labels ─────────────────────────────────────────────
+
+  function buildFileRules() {
+    return fileRulesDef.map((rule, i) => {
+      let test;
+      if (rule.prefix) test = p => p.startsWith(rule.prefix);
+      else if (rule.suffix) test = p => p.endsWith(rule.suffix);
+      else if (rule.exact) test = p => p === rule.exact;
+      else if (rule.pattern) {
+        const re = new RegExp(rule.pattern);
+        test = p => re.test(p);
+      } else {
+        throw new Error(
+          `fileRules[${i}] (label: "${rule.label}") has no recognized matcher ` +
+          `(expected one of: prefix, suffix, exact, pattern)`
+        );
+      }
+      return { label: rule.label, test };
+    });
+  }
+
+  function matchFileLabels(files, fileRules) {
+    const rules = fileRules || buildFileRules();
+    const labels = new Set();
+    for (const rule of rules) {
+      if (files.some(f => rule.test(f.filename ?? ''))) {
+        labels.add(rule.label);
+      }
+    }
+    return labels;
+  }
+
+  // ── Title-based labels ────────────────────────────────────────────
+
+  function matchTitleLabels(title) {
+    const labels = new Set();
+    const m = (title ?? '').match(/^(\w+)(?:\(([^)]+)\))?(!)?:/);
+    if (!m) return { labels, type: null, typeLabel: null, scopes: [], breaking: false };
+
+    const type = m[1].toLowerCase();
+    const scopeStr = m[2] ?? '';
+    const breaking = !!m[3];
+
+    const typeLabel = typeToLabel[type] || null;
+    if (typeLabel) labels.add(typeLabel);
+    if (breaking) labels.add('breaking');
+
+    const scopes = scopeStr.split(',').map(s => s.trim()).filter(Boolean);
+    for (const scope of scopes) {
+      const sl = scopeToLabel[scope];
+      if (sl) labels.add(sl);
+    }
+
+    return { labels, type, typeLabel, scopes, breaking };
+  }
+
+  // ── Org membership ────────────────────────────────────────────────
+
+  async function checkMembership(author, userType) {
+    if (userType === 'Bot') {
+      console.log(`${author} is a Bot — treating as internal`);
+      return { isExternal: false };
+    }
+
+    try {
+      const membership = await github.rest.orgs.getMembershipForUser({
+        org: 'langchain-ai',
+        username: author,
+      });
+      const isExternal = membership.data.state !== 'active';
+      console.log(
+        isExternal
+          ? `${author} has pending membership — treating as external`
+          : `${author} is an active member of langchain-ai`,
+      );
+      return { isExternal };
+    } catch (e) {
+      if (e.status === 404) {
+        console.log(`${author} is not a member of langchain-ai`);
+        return { isExternal: true };
+      }
+      // Non-404 errors (rate limit, auth failure, server error) must not
+      // silently default to external — rethrow to fail the step.
+      throw new Error(
+        `Membership check failed for ${author} (${e.status}): ${e.message}`,
+      );
+    }
+  }
+
+  // ── Contributor analysis ──────────────────────────────────────────
+
+  async function getContributorInfo(contributorCache, author, userType) {
+    if (contributorCache.has(author)) return contributorCache.get(author);
+
+    const { isExternal } = await checkMembership(author, userType);
+
+    let mergedCount = null;
+    if (isExternal) {
+      try {
+        const result = await github.rest.search.issuesAndPullRequests({
+          q: `repo:${owner}/${repo} is:pr is:merged author:"${author}"`,
+          per_page: 1,
+        });
+        mergedCount = result?.data?.total_count ?? null;
+      } catch (e) {
+        if (e?.status !== 422) throw e;
+        const core = require('@actions/core');
+        core.warning(`Search failed for ${author}; skipping tier.`);
+      }
+    }
+
+    const info = { isExternal, mergedCount };
+    contributorCache.set(author, info);
+    return info;
+  }
+
+  // ── Tier label resolution ───────────────────────────────────────────
+
+  async function applyTierLabel(issueNumber, author, { skipNewContributor = false } = {}) {
+    const core = require('@actions/core');
+    let mergedCount;
+    try {
+      const result = await github.rest.search.issuesAndPullRequests({
+        q: `repo:${owner}/${repo} is:pr is:merged author:"${author}"`,
+        per_page: 1,
+      });
+      mergedCount = result?.data?.total_count;
+    } catch (error) {
+      if (error?.status !== 422) throw error;
+      core.warning(`Search failed for ${author}; skipping tier label.`);
+      return;
+    }
+
+    if (mergedCount == null) {
+      core.warning(`Search response missing total_count for ${author}; skipping tier label.`);
+      return;
+    }
+
+    let tierLabel = null;
+    if (mergedCount >= trustedThreshold) tierLabel = 'trusted-contributor';
+    else if (mergedCount === 0 && !skipNewContributor) tierLabel = 'new-contributor';
+
+    if (tierLabel) {
+      await ensureLabel(tierLabel);
+      await github.rest.issues.addLabels({
+        owner, repo, issue_number: issueNumber, labels: [tierLabel],
+      });
+      console.log(`Applied '${tierLabel}' to #${issueNumber} (${mergedCount} merged PRs)`);
+    } else {
+      console.log(`No tier label for ${author} (${mergedCount} merged PRs)`);
+    }
+
+    return tierLabel;
+  }
+
+  return {
+    ensureLabel,
+    getSizeLabel,
+    computeSize,
+    buildFileRules,
+    matchFileLabels,
+    matchTitleLabels,
+    allTypeLabels,
+    checkMembership,
+    getContributorInfo,
+    applyTierLabel,
+    sizeLabels,
+    tierLabels,
+    trustedThreshold,
+    labelColor,
+  };
+}
+
+function loadAndInit(github, owner, repo) {
+  const config = loadConfig();
+  return { config, h: init(github, owner, repo, config) };
+}
+
+module.exports = { loadConfig, init, loadAndInit };