tiangolo/fastapi · error · RuntimeError

Couldn't auto-generate sponsors section

Error message

Couldn't auto-generate sponsors section

What it means

Raised by generate_readme_content() in scripts/docs.py:357 when it cannot locate the sponsor placeholder markers in docs/en/docs/index.md. The README is generated by slicing index.md between the markers '<!-- sponsors -->' and '<!-- /sponsors -->' (scripts/docs.py:352-353) and injecting rendered sponsor HTML. If either marker is absent the slice boundaries are undefined, so the function aborts rather than emit a malformed README.

Source

Thrown at scripts/docs.py:357

        match = header_with_permalink_pattern.match(line)
        if match:
            hashes, title, *_ = match.groups()
            line = f"{hashes} {title}"
        lines.append(line)
    return "\n".join(lines)


def generate_readme_content() -> str:
    en_index = en_docs_path / "docs" / "index.md"
    content = en_index.read_text("utf-8")
    content = remove_header_permalinks(content)  # remove permalinks from headers
    match_pre = re.search(r"</style>\n\n", content)
    match_start = re.search(r"<!-- sponsors -->", content)
    match_end = re.search(r"<!-- /sponsors -->", content)
    sponsors_data_path = en_docs_path / "data" / "sponsors.yml"
    sponsors = yaml.safe_load(sponsors_data_path.read_text(encoding="utf-8"))
    if not (match_start and match_end):
        raise RuntimeError("Couldn't auto-generate sponsors section")
    if not match_pre:
        raise RuntimeError("Couldn't find pre section (<style>) in index.md")
    frontmatter_end = match_pre.end()
    pre_end = match_start.end()
    post_start = match_end.start()
    template = Template(index_sponsors_template)
    message = template.render(sponsors=sponsors, sponsor_img_url=sponsor_img_url)
    pre_content = content[frontmatter_end:pre_end]
    post_content = content[post_start:]
    new_content = pre_content + message + post_content
    # Remove content between <!-- only-mkdocs --> and <!-- /only-mkdocs -->
    new_content = re.sub(
        r"<!-- only-mkdocs -->.*?<!-- /only-mkdocs -->",
        "",
        new_content,
        flags=re.DOTALL,
    )
    return new_content

View on GitHub (pinned to 3e8d1526d8)

Solutions

1. Open docs/en/docs/index.md and confirm both '<!-- sponsors -->' and '<!-- /sponsors -->' are present exactly as written.
2. Restore the markers from git history: git log -p -- docs/en/docs/index.md | grep -n 'sponsors'.
3. Re-run generate-readme once both markers exist.

Example fix

<!-- before: markers missing -->
## FastAPI
...
<!-- after: restore both markers -->
## FastAPI
<!-- sponsors -->
<!-- /sponsors -->

from pathlib import Path

def has_sponsor_markers(index_md: Path) -> bool:
    text = index_md.read_text(encoding="utf-8")
    return "<!-- sponsors -->" in text and "<!-- /sponsors -->" in text

try:
    content = generate_readme_content()
except RuntimeError as e:
    if "sponsors" in str(e):
        raise RuntimeError("index.md is missing sponsor markers; restore them") from e
    raise

When it happens

Trigger: Running `python scripts/docs.py generate-readme` (or any workflow calling generate_readme_content) after the sponsor markers were removed or renamed in docs/en/docs/index.md. Fires when match_start or match_end is falsy at scripts/docs.py:356.

Common situations: Someone edited index.md and deleted/renamed the sponsor HTML comment markers. A find-and-replace rewrote HTML comments. The index.md file was regenerated from a template that omits the markers.

Related errors

• Couldn't find pre section (<style>) in index.md
• Code block (lines {start_line}-{end_line_no}) has different
• Number of code blocks does not match the number in the origi
• {release_notes_file} must start with {RELEASE_NOTES_HEADER!r
• {release_notes_file} must start with {latest_header!r}

AI-assisted analysis of tiangolo/fastapi@3e8d1526d8 (2026-08-11). Data as JSON: /api/errors/a8cfcccbfe22a12e. Report an issue: GitHub.