[Github] Action to Auto-assign PR Reviewers (that respects CODEOWNERS.md and overrides)

.github/module-owners.json

@@ -0,0 +1,39 @@
+{
+    "Generic Runtime": ["funatiq", "pcastonguay", "Shixiaowei02", "MartinMarciniszyn", "schetlur-nv", "dcampora"],
+    "Triton Backend": ["Tabrizian", "pcastonguay", "schetlur-nv"],
+    "LLM API/Workflow": ["Superjomn", "syuoni", "nv-guomingz", "litaotju", "QiJune"],
+    "KV-Cache Management":["thorjohnsen", "schetlur-nv"],
+    "Low Precision":["Tracin", "nv-guomingz", "Naveassaf"],
+    "Speculative Decoding":["yweng0828", "nekorobov", "lfr-0531"],
+    "Customized Kernels":["lowsfer", "PerkzZheng", "jdemouth-nvidia"],
+    "Performance": ["kaiyux", "jiahanc", "hypdeb"],
+    "Lora/P-tuning":["byshiue", "shaharmor98"],
+    "Disaggregated Serving":["Shixiaowei02", "joyang-nv", "chuangz0", "schetlur-nv"],
+    "Documentation":["nv-guomingz"],
+    "Sampling": ["dcampora", "lfr-0531", "Naveassaf", "syuoni", "yweng0828"],
+    "Memory": ["litaotju", "peaceh-nv"],
+    "Installation": ["hchings", "Superjomn", "nv-guomingz", "QiJune"],
+    "GitHub Configuration": ["tburt-nv", "niukuo"],
+    "Jenkins Pipelines": ["chzblych", "niukuo"],
+    "Test Configuration": ["niukuo", "syuoni", "LarryXFly"],
+    "Test Waive List": ["chzblych", "niukuo"],
+    "Integration Tests": ["LarryXFly", "niukuo"],
+    "Torch Framework": ["QiJune", "hlu1"],
+    "Torch Attention Backend": ["yuxianq", "hlu1"],
+    "Torch AutoDeploy": ["lucaslie", "suyoggupta"],
+    "Torch Compilation": ["litaotju", "yizhang-nv", "liji-nv"],
+    "Torch Custom Ops": ["yizhang-nv"],
+    "Torch Distributed": ["yilin-void", "yuxianq", "hyukn", "yizhang-nv", "hlu1"],
+    "Torch PyExecutor": ["dongxuy04", "funatiq", "dcampora", "HuiGao-NV"],
+    "Torch Speculative": ["lfr-0531", "mikeiovine"],
+    "Autotuner": ["hyukn", "litaotju"],
+    "Pipeline Interface": ["amukkara", "chang-l"],
+    "Torch Models": ["QiJune", "hlu1"],
+    "Torch Models DeepSeekV3": ["hlu1", "zongfeijing"],
+    "Torch Models Llama": ["chang-l", "mikeiovine"],
+    "Torch Modules": ["QiJune", "hlu1"],
+    "Torch Modules Attention": ["yuxianq", "hlu1"],
+    "Torch Modules Fused MOE": ["hlu1", "dongxuy04", "zongfeijing", "HuiGao-NV"],
+    "Torch Tests": ["QiJune", "hlu1"],
+    "PyTorch Examples": ["QiJune", "hlu1"]
+}

.github/module-paths.json

@@ -0,0 +1,33 @@
+{
+    "cpp/": "Generic Runtime",
+    "triton_backend/": "Triton Backend",
+    "tensorrt_llm/_torch/peft/": "Lora/P-tuning",
+    "tensorrt_llm/": "LLM API/Workflow",
+    "benchmarks/": "Performance",
+    "examples/disaggregated/": "Disaggregated Serving",
+    "docs/": "Documentation",
+    "docker/": "Installation",
+    ".github/": "GitHub Configuration",
+    "jenkins/": "Jenkins Pipelines",
+    "tests/integration/test_lists/": "Test Configuration",
+    "tests/integration/test_lists/waives.txt": "Test Waive List",
+    "tests/integration/defs/": "Integration Tests",
+    "tensorrt_llm/_torch/": "Torch Framework",
+    "tensorrt_llm/_torch/attention_backend/": "Torch Attention Backend",
+    "tensorrt_llm/_torch/auto_deploy/": "Torch AutoDeploy",
+    "tensorrt_llm/_torch/compilation/": "Torch Compilation",
+    "tensorrt_llm/_torch/custom_ops/": "Torch Custom Ops",
+    "tensorrt_llm/_torch/distributed/": "Torch Distributed",
+    "tensorrt_llm/_torch/pyexecutor/": "Torch PyExecutor",
+    "tensorrt_llm/_torch/speculative/": "Torch Speculative",
+    "tensorrt_llm/autotuner.py": "Autotuner",
+    "tensorrt_llm/pipeline_interface.py": "Pipeline Interface",
+    "tensorrt_llm/_torch/models/": "Torch Models",
+    "tensorrt_llm/_torch/models/modeling_deepseekv3.py": "Torch Models DeepSeekV3",
+    "tensorrt_llm/_torch/models/modeling_llama.py": "Torch Models Llama",
+    "tensorrt_llm/_torch/modules/": "Torch Modules",
+    "tensorrt_llm/_torch/modules/attention.py": "Torch Modules Attention",
+    "tensorrt_llm/_torch/modules/fused_moe.py": "Torch Modules Fused MOE",
+    "tests/unittest/_torch/": "Torch Tests",
+    "examples/pytorch/": "PyTorch Examples"
+}

.github/scripts/assign_reviewers.py

@@ -0,0 +1,295 @@
+import argparse
+import json
+import os
+import random
+import subprocess
+import sys
+from pathlib import Path
+
+
+def get_pr_changed_files(pr_number: str) -> list[str]:
+    """Get files changed in PR using GitHub CLI (more reliable than git diff)"""
+    result = subprocess.run(
+        [
+            "gh", "pr", "view", pr_number, "--json", "files", "--jq",
+            ".files[].path"
+        ],
+        capture_output=True,
+        text=True,
+        check=True,
+    )
+    return [line.strip() for line in result.stdout.splitlines() if line.strip()]
+
+
+def get_existing_reviewers(pr_number: str) -> tuple[set[str], set[str]]:
+    """Get currently assigned reviewers (users and teams) for a PR"""
+    try:
+        # Get user reviewers
+        user_result = subprocess.run(
+            [
+                "gh", "pr", "view", pr_number, "--json", "reviewRequests",
+                "--jq",
+                "(.reviewRequests // []) | .[] | select(.login) | .login"
+            ],
+            capture_output=True,
+            text=True,
+            check=True,
+        )
+        user_reviewers = {
+            line.strip()
+            for line in user_result.stdout.splitlines() if line.strip()
+        }
+
+        # Get team reviewers
+        team_result = subprocess.run(
+            [
+                "gh", "pr", "view", pr_number, "--json", "reviewRequests",
+                "--jq", "(.reviewRequests // []) | .[] | select(.name) | .name"
+            ],
+            capture_output=True,
+            text=True,
+            check=True,
+        )
+        team_reviewers = {
+            line.strip()
+            for line in team_result.stdout.splitlines() if line.strip()
+        }
+
+        return user_reviewers, team_reviewers
+    except subprocess.CalledProcessError as e:
+        print(f"Warning: Could not fetch existing reviewers: {e}")
+        return set(), set()
+
+
+def load_json(path: str):
+    with open(path, "r", encoding="utf-8") as f:
+        return json.load(f)
+
+
+def map_modules(changed_files: list[str],
+                module_paths: dict[str, str]) -> tuple[set[str], list[str]]:
+    """Map changed files to modules using MOST SPECIFIC (longest) prefix match"""
+    modules: set[str] = set()
+    unmapped_files: list[str] = []
+
+    for file in changed_files:
+        # Find ALL matching prefixes
+        matches = []
+        for prefix, module in module_paths.items():
+            if file.startswith(prefix):
+                matches.append((len(prefix), prefix, module))
+
+        if matches:
+            # Sort by prefix length (descending) to get most specific first
+            matches.sort(reverse=True)
+            most_specific_module = matches[0][2]
+            modules.add(most_specific_module)
+
+            # Log if there were multiple matches (for debugging)
+            if len(matches) > 1:
+                matches[0][1]
+                print(f"  File '{file}' has overlapping mappings:")
+                for _, prefix, module in matches:
+                    marker = "→" if module == most_specific_module else " "
+                    print(f"    {marker} {prefix} -> {module}")
+        else:
+            unmapped_files.append(file)
+
+    return modules, unmapped_files
+
+
+def gather_reviewers(
+    modules: set[str],
+    module_owners: dict[str, list[str]],
+    *,
+    pr_author: str | None = None,
+    existing_reviewers: set[str] | None = None,
+    per_module_limit: int = 2
+) -> tuple[list[str], dict[str, list[str]], set[str]]:
+    """
+    Gather reviewers ensuring each module gets representation.
+
+    Args:
+        modules: Set of module names that were touched
+        module_owners: Dict mapping module names to lists of owners
+        pr_author: PR author to exclude from reviewers
+        existing_reviewers: Set of already assigned reviewers to exclude
+        per_module_limit: Maximum reviewers to assign per module
+
+    Returns:
+        - List of all unique reviewers to assign
+        - Dict mapping modules to their assigned reviewers
+        - Set of modules without owners
+    """
+    all_reviewers: set[str] = set()
+    module_assignments: dict[str, list[str]] = {}
+    modules_without_owners: set[str] = set()
+
+    for module in sorted(modules):  # Sort for consistent ordering
+        owners = module_owners.get(module, [])
+        if not owners:
+            modules_without_owners.add(module)
+            module_assignments[module] = []
+            continue
+
+        # Filter out PR author and existing reviewers
+        eligible_owners = [
+            o for o in owners if o != pr_author and (
+                not existing_reviewers or o not in existing_reviewers)
+        ]
+
+        if not eligible_owners:
+            # All owners are excluded
+            print(
+                f"  ⚠️  Module '{module}': All owners excluded (PR author or already assigned)"
+            )
+            module_assignments[module] = []
+            continue
+
+        # Sample up to per_module_limit reviewers for this module
+        num_to_select = min(len(eligible_owners), per_module_limit)
+        selected = random.sample(eligible_owners, num_to_select)
+
+        module_assignments[module] = selected
+        all_reviewers.update(selected)
+
+    return sorted(all_reviewers), module_assignments, modules_without_owners
+
+
+def main() -> None:
+    parser = argparse.ArgumentParser(
+        description="Assign reviewers based on changed modules")
+    parser.add_argument("--dry-run",
+                        action="store_true",
+                        help="Print the gh command instead of executing")
+    parser.add_argument(
+        "--force-assign",
+        action="store_true",
+        help=
+        "Assign reviewers even if some already exist (default: only assign if no reviewers)"
+    )
+    args = parser.parse_args()
+
+    pr_number = os.environ["PR_NUMBER"]
+    per_module_limit = int(os.environ.get("PER_MODULE_REVIEWER_LIMIT", "2"))
+    pr_author = os.environ.get("PR_AUTHOR")
+
+    print(f"Testing PR #{pr_number} with author: {pr_author}")
+    print(f"Per-module reviewer limit: {per_module_limit}")
+
+    # Check existing reviewers
+    existing_user_reviewers, existing_team_reviewers = get_existing_reviewers(
+        pr_number)
+    total_existing = len(existing_user_reviewers) + len(existing_team_reviewers)
+
+    print(f"Existing user reviewers: {sorted(existing_user_reviewers)}")
+    print(f"Existing team reviewers: {sorted(existing_team_reviewers)}")
+
+    # Skip assignment if reviewers already exist (unless forced)
+    if total_existing > 0 and not args.force_assign:
+        print(
+            f"✅ PR already has {total_existing} reviewer(s) assigned. Skipping auto-assignment."
+        )
+        print("   Use --force-assign to assign additional reviewers.")
+        return
+
+    try:
+        changed_files = get_pr_changed_files(pr_number)
+        print(f"Changed files: {changed_files}")
+
+        module_paths = load_json(Path(".github") / "module-paths.json")
+        module_owners = load_json(Path(".github") / "module-owners.json")
+
+        modules, unmapped_files = map_modules(changed_files, module_paths)
+        reviewers, module_assignments, modules_without_owners = gather_reviewers(
+            modules,
+            module_owners,
+            pr_author=pr_author,
+            existing_reviewers=
+            existing_user_reviewers,  # Avoid re-assigning existing users
+            per_module_limit=per_module_limit)
+
+        print(f"\nChanged modules: {sorted(modules)}")
+
+        # Show module-specific assignments
+        if module_assignments:
+            print("\nModule assignments:")
+            for module, assigned in sorted(module_assignments.items()):
+                if assigned:
+                    print(f"  {module}: {assigned}")
+                else:
+                    print(f"  {module}: No eligible reviewers")
+
+        print(f"\nFinal reviewers to assign: {reviewers}")
+
+        # Provide detailed feedback about coverage gaps
+        if unmapped_files:
+            print(f"⚠️  Files with no module mapping: {unmapped_files}")
+            print(
+                f"   These files are not covered in .github/module-paths.json")
+            print(
+                f"   Consider adding appropriate module mappings for these paths."
+            )
+
+        if modules_without_owners:
+            print(
+                f"⚠️  Modules with no owners: {sorted(modules_without_owners)}")
+            print(
+                f"   These modules exist in module-paths.json but have no owners in module-owners.json"
+            )
+            print(f"   Consider adding owner assignments for these modules.")
+
+        if reviewers:
+            cmd = ["gh", "pr", "edit", pr_number]
+            for reviewer in reviewers:
+                cmd.extend(["--add-reviewer", reviewer])
+
+            if args.dry_run:
+                print(f"🔍 DRY RUN: {' '.join(cmd)}")
+            else:
+                try:
+                    subprocess.run(cmd, check=True)
+                    print(
+                        f"✅ Successfully assigned {len(reviewers)} new reviewer(s)"
+                    )
+                except subprocess.CalledProcessError as e:
+                    print(f"❌ Failed to add reviewers: {e}", file=sys.stderr)
+                    print(
+                        "   This might be due to permissions or invalid usernames"
+                    )
+                    sys.exit(1)
+        else:
+            print("✅ No new reviewers to assign")
+
+            # Explain why no reviewers were assigned
+            if not modules and not unmapped_files:
+                print("   Reason: No files were changed in this PR")
+            elif not modules and unmapped_files:
+                print(
+                    "   Reason: All changed files are unmapped (no module coverage)"
+                )
+                print(
+                    "   ➜ Action needed: Add module mappings to .github/module-paths.json"
+                )
+            elif modules and not reviewers:
+                if modules_without_owners:
+                    print("   Reason: Matched modules have no assigned owners")
+                    print(
+                        "   ➜ Action needed: Add owner assignments to .github/module-owners.json"
+                    )
+                else:
+                    print(
+                        "   Reason: All potential reviewers are already assigned or excluded"
+                    )
+            else:
+                print(
+                    "   Reason: Complex combination of mapping/ownership issues (see warnings above)"
+                )
+
+    except subprocess.CalledProcessError as e:
+        print(f"❌ Error processing PR: {e}", file=sys.stderr)
+        sys.exit(1)
+
+
+if __name__ == "__main__":
+    main()