tiangolo/fastapi · error · RuntimeError

No github event file available at: {settings.github_event_pa

Error message

No github event file available at: {settings.github_event_path}

What it means

Raised by notify_translations.main() at scripts/notify_translations.py:316 when settings.github_event_path does not point to an existing file. The script reads the GitHub Actions event payload from that path (set by GitHub Actions as GITHUB_EVENT_PATH) to discover the triggering pull request. Without it the run cannot determine which PR to act on.

Source

Thrown at scripts/notify_translations.py:316

        query=update_comment_mutation,
        comment_id=comment_id,
        body=body,
    )
    response = UpdateCommentResponse.model_validate(data)
    return response.data.updateDiscussionComment.comment


def main() -> None:
    settings = Settings()
    if settings.debug:
        logging.basicConfig(level=logging.DEBUG)
    else:
        logging.basicConfig(level=logging.INFO)
    logging.debug(f"Using config: {settings.model_dump_json()}")
    g = Github(settings.github_token.get_secret_value())
    repo = g.get_repo(settings.github_repository)
    if not settings.github_event_path.is_file():
        raise RuntimeError(
            f"No github event file available at: {settings.github_event_path}"
        )
    contents = settings.github_event_path.read_text("utf-8")
    github_event = PartialGitHubEvent.model_validate_json(contents)
    logging.info(f"Using GitHub event: {github_event}")
    number = (
        github_event.pull_request and github_event.pull_request.number
    ) or settings.number
    if number is None:
        raise RuntimeError("No PR number available")
    number = cast(int, number)

    # Avoid race conditions with multiple labels
    sleep_time = random.random() * 10  # random number between 0 and 10 seconds
    logging.info(
        f"Sleeping for {sleep_time} seconds to avoid "
        "race conditions and multiple comments"
    )

View on GitHub (pinned to 3e8d1526d8)

Solutions

Run the script only inside a pull_request / pull_request_target GitHub Actions job where GITHUB_EVENT_PATH is populated.
For local testing, export GITHUB_EVENT_PATH pointing to a saved PR event JSON and set the other Settings env vars (GITHUB_REPOSITORY, GITHUB_TOKEN).
If the runner lost the file, re-run the job on a fresh runner.

Example fix

# before — running locally with no event file
python scripts/notify_translations.py
# after — point at a saved PR event payload
GITHUB_EVENT_PATH=./pr_event.json GITHUB_REPOSITORY=fastapi/fastapi GITHUB_TOKEN=*** python scripts/notify_translations.py

Defensive patterns

Strategy: validation

Validate before calling

import os
from pathlib import Path

def event_path_ok() -> bool:
    p = os.environ.get("GITHUB_EVENT_PATH")
    return bool(p) and Path(p).is_file()

Try / catch

if not settings.github_event_path.is_file():
    logging.error(f"Missing event file at {settings.github_event_path}")
    sys.exit(1)

Prevention

Only run notify_translations in pull_request / pull_request_target jobs.
For local runs, export GITHUB_EVENT_PATH pointing at a saved PR event JSON.
Document the required env vars (GITHUB_EVENT_PATH, GITHUB_REPOSITORY, GITHUB_TOKEN) in the workflow.

When it happens

Trigger: Running scripts/notify_translations.py outside GitHub Actions without setting GITHUB_EVENT_PATH, or in an action that does not populate it (e.g. workflow_dispatch without an event payload). Fires at scripts/notify_translations.py:315 where it checks settings.github_event_path.is_file().

Common situations: Local debugging run with no env var. Wrong job trigger (schedule, repository_dispatch) where GITHUB_EVENT_PATH still exists but is empty or stale — here it is genuinely absent. Runner environment corruption where the event file was deleted.

Related errors

AI-assisted analysis of tiangolo/fastapi@3e8d1526d8 (2026-08-11). Data as JSON: /api/errors/cbbd834659443b3e. Report an issue: GitHub.