microsoft/autogen · error · ImportError

The 'unidiff' package is required for patch application. Ins

Error message

The 'unidiff' package is required for patch application. Install with 'pip install unidiff'.

What it means

apply_patch needs the third-party 'unidiff' library to parse and apply unified diffs. The import is optional (PatchSet is None if unidiff is absent) and this ImportError tells you to install it; the chained guidance is 'pip install unidiff' or the chromadb-style extra.

Source

Thrown at python/packages/autogen-ext/src/autogen_ext/memory/canvas/_text_canvas.py:151

            fromfile=f"{filename}@r{from_revision}",
            tofile=f"{filename}@r{to_revision}",
        )
        return "".join(diff)

    def apply_patch(self, filename: str, patch_data: Union[str, bytes, Any]) -> None:
        """Apply *patch_text* (unified diff) to the latest revision and save a new revision.

        Uses the *unidiff* library to accurately apply hunks and validate context lines.
        """
        if isinstance(patch_data, bytes):
            patch_data = patch_data.decode("utf-8")
        if not isinstance(patch_data, str):
            raise ValueError(f"Expected str or bytes, got {type(patch_data)}")
        self._ensure_file(filename)
        original_content = self.get_latest_content(filename)

        if PatchSet is None:
            raise ImportError(
                "The 'unidiff' package is required for patch application. Install with 'pip install unidiff'."
            )

        patch = PatchSet(patch_data)
        # Our canvas stores exactly one file per patch operation so we
        # use the first (and only) patched_file object.
        if not patch:
            raise ValueError("Empty patch text provided.")
        patched_file = patch[0]
        working_lines = original_content.splitlines(keepends=True)
        line_offset = 0
        for hunk in patched_file:
            # Calculate the slice boundaries in the *current* working copy.
            start = hunk.source_start - 1 + line_offset
            end = start + hunk.source_length
            # Build the replacement block for this hunk.
            replacement: List[str] = []
            for line in hunk:

View on GitHub (pinned to 027ecf0a37)

Solutions

Install unidiff: pip install unidiff (or install the autogen-ext extra that includes it).
Verify with python -c "import unidiff" after installing.
Add unidiff to your project's dependency list so CI environments include it.

Example fix

# shell
# before: apply_patch raises ImportError
pip install unidiff
# after: apply_patch works

Defensive patterns

Strategy: validation

Validate before calling

try:
    import unidiff  # noqa: F401
    unidiff_available = True
except ImportError:
    unidiff_available = False
if not unidiff_available:
    raise RuntimeError("unidiff required: pip install unidiff") before running apply_patch flows

Try / catch

try:
    canvas.apply_patch(filename, patch_text)
except ImportError as e:
    if "unidiff" in str(e):
        subprocess.check_call([sys.executable, "-m", "pip", "install", "unidiff"])
        canvas.apply_patch(filename, patch_text)
    else:
        raise

Prevention

Declare unidiff in your project dependencies since apply_patch needs it.
Smoke-test `import unidiff` in environment setup scripts for apps that patch canvas files.

When it happens

Trigger: Calling apply_patch on TextCanvas in an environment where the unidiff package is not installed (it is an optional dependency of the canvas extra).

Common situations: Fresh environments where only the base autogen-ext package was installed; CI images trimmed of optional deps; dependency lock files that dropped the transitive extra.

Related errors

AI-assisted analysis of microsoft/autogen@027ecf0a37 (2026-08-15). Data as JSON: /api/errors/3bc7df398cb00872. Report an issue: GitHub.