HKUDS/DeepTutor · warning · ManimRenderError

Image mode code must only contain YON_IMAGE anchor blocks.

Error message

Image mode code must only contain YON_IMAGE anchor blocks.

What it means

Raised by _extract_text_like when FileTypeRouter.decode_bytes throws while decoding a text-like file (.txt, .md, .py, etc.). Marked 'pragma: no cover' because decode_bytes is designed never to raise (it falls back across encodings), so hitting this indicates an unexpected decoding-layer failure.

Source

Thrown at deeptutor/agents/math_animator/renderer.py:93

            code_path=code_path, scene_name=scene_name, quality=quality, save_last_frame=False
        )
        video_file = self._find_rendered_file(".mp4")
        target_name = slugify_filename(f"{self.turn_id}-{scene_name}.mp4", f"{self.turn_id}.mp4")
        artifact_path = self.artifacts_dir / target_name
        artifact_path.write_bytes(video_file.read_bytes())
        await self._emit_progress(f"Saved rendered video as {artifact_path.name}.")
        return self._build_artifact(artifact_path, "video", "video/mp4", "Animation video")

    async def _render_image_blocks(self, *, code: str, quality: str) -> list[RenderedArtifact]:
        matches = list(YON_IMAGE_PATTERN.finditer(code))
        if not matches:
            raise ManimRenderError(
                "Image mode requires code blocks wrapped in ### YON_IMAGE_n_START ### / END ###."
            )

        residual = YON_IMAGE_PATTERN.sub("", code).strip()
        if residual:
            raise ManimRenderError("Image mode code must only contain YON_IMAGE anchor blocks.")

        artifacts: list[RenderedArtifact] = []
        for idx, match in enumerate(matches, start=1):
            block_code = match.group(2).strip()
            block_path = self.source_dir / f"image_block_{idx:02d}.py"
            block_path.write_text(block_code, encoding="utf-8")
            scene_name = self._extract_scene_name(block_code)
            await self._emit_progress(
                f"Rendering image block {idx}/{len(matches)} with scene `{scene_name}`."
            )
            await self._run_manim(
                code_path=block_path,
                scene_name=scene_name,
                quality=quality,
                save_last_frame=True,
            )
            image_file = self._find_rendered_file(".png")
            artifact_path = self.artifacts_dir / f"image-{idx:02d}.png"

View on GitHub (pinned to 3e82f13042)

Solutions

1. Inspect the raw bytes (hexdump) to identify the actual encoding/corruption
2. Ensure FileTypeRouter.decode_bytes fallbacks are intact if you forked the class
3. Rename/re-classify the file if it is actually binary with a text extension

Example fix

// before
text = _extract_text_like(data, "weird.txt")  # raises

// after
text = data.decode("utf-8", errors="replace")  # manual tolerant decode as last resort

try:
    FileTypeRouter.decode_bytes(data)
except Exception:
    data = data.decode("utf-8", errors="replace").encode("utf-8")  # sanitize

except CorruptDocumentError as e:
    if "failed to decode text" in str(e):
        text = data.decode("utf-8", errors="replace")

When it happens

Trigger: Bytes that defeat every fallback encoding in FileTypeRouter.decode_bytes — extremely malformed byte sequences or a decode implementation that raises a non-UnicodeDecodeError (e.g. MemoryError or a LookupError for an unknown codec).

Common situations: Essentially unreachable in normal use; would surface only after changes to FileTypeRouter or pathological binary payloads mislabeled with text extensions.

AI-assisted analysis of HKUDS/DeepTutor@3e82f13042 (2026-08-27). Data as JSON: /api/errors/8f32d80a9d57fa3d. Report an issue: GitHub.