langflow-ai/langflow · error · SystemExit

Could not locate the {what} end marker ({needle!r}) in pypro

Error message

Could not locate the {what} end marker ({needle!r}) in pyproject.toml.  Re-add the ``langflow-extensions:bundle-*`` marker pair before re-running -- see src/bundles/PORTING.md.

What it means

port_bundle.py edits the root pyproject.toml by inserting generated blocks (workspace member, dependency entries, etc.) immediately before a sentinel 'end marker' comment — the langflow-extensions:bundle-* marker pair. _insert_before_marker does a plain text.find() for the needle; if the marker comment was deleted or reworded, find returns -1 and the script exits with this error, instructing you to restore the marker pair (documented in src/bundles/PORTING.md) before re-running.

Source

Thrown at scripts/migrate/port_bundle.py:1133

    ROOT_PYPROJECT.write_text(text, encoding="utf-8")
    return actions


# ---------------------------------------------------------------------------
# Phase C: workspace + external consumers
# ---------------------------------------------------------------------------


def _insert_before_marker(text: str, end_marker: str, payload: str, *, what: str) -> str:
    needle = end_marker
    idx = text.find(needle)
    if idx == -1:
        msg = (
            f"Could not locate the {what} end marker ({needle!r}) in "
            "pyproject.toml.  Re-add the ``langflow-extensions:bundle-*`` "
            "marker pair before re-running -- see src/bundles/PORTING.md."
        )
        raise SystemExit(msg)
    line_start = text.rfind("\n", 0, idx) + 1
    return text[:line_start] + payload + text[line_start:]


def _patch_root_pyproject(plan: PortPlan, *, apply: bool) -> list[str]:
    actions = [f"patch {ROOT_PYPROJECT.relative_to(REPO_ROOT)}"]
    if not apply:
        return actions
    text = ROOT_PYPROJECT.read_text(encoding="utf-8")
    bundle = plan.bundle

    if f"lfx-{bundle}" in text:
        msg = f"lfx-{bundle} already referenced in {ROOT_PYPROJECT.relative_to(REPO_ROOT)}; not patching."
        raise SystemExit(msg)

    dep_line = f'    "lfx-{bundle}>=0.1.0",\n'
    source_line = f"lfx-{bundle} = {{ workspace = true }}\n"
    member_line = f'    "src/bundles/{bundle}",\n'

View on GitHub (pinned to 976ec789d2)

Solutions

1. Restore the marker pair in pyproject.toml exactly as documented in src/bundles/PORTING.md (grep another bundle's markers for the exact wording: `grep -n 'langflow-extensions:bundle' pyproject.toml`).
2. Re-run `python scripts/migrate/port_bundle.py --bundle <name> --apply`; insertion is idempotent with respect to the markers.
3. Add the marker comments to any protected-comment list in your formatter config so they survive future cleanups.

Example fix

# before (pyproject.toml)
# marker comment deleted by cleanup PR

# after (pyproject.toml)
# langflow-extensions:bundle-start
...
# langflow-extensions:bundle-end

from pathlib import Path

NEEDLES = ("langflow-extensions:bundle",)  # match the exact markers from PORTING.md

def markers_present(pyproject: Path) -> bool:
    text = pyproject.read_text(encoding="utf-8")
    return all(needle in text for needle in NEEDLES)

When it happens

Trigger: Running port_bundle.py --apply when the `# langflow-extensions:bundle-...-end` (or corresponding) marker comment has been removed from pyproject.toml — by a cleanup PR, an aggressive formatter, or a manual edit that assumed the comment was decorative.

Common situations: Comment-stripping formatters or linters; someone reorganizing the workspace/deps sections and dropping 'unused' comments; merge conflicts resolved without preserving markers.

Related errors

• Could not strip ruff per-file-ignore entry for {ri.pattern!r
• lfx-{bundle} already referenced in {ROOT_PYPROJECT.relative_
• provider directory not found: {src}
• destination already exists (already consolidated?): {dst}
• {provider}: source has subdirectory/ies {subdirs} that move_

AI-assisted analysis of langflow-ai/langflow@976ec789d2 (2026-08-14). Data as JSON: /api/errors/10768d1799f1549c. Report an issue: GitHub.