BUG: read_csv throws TypeError with iterator, nrows

[mdavis-xyz]

Pandas version checks

• I have checked that this issue has not already been reported.

• I have confirmed this bug exists on the latest version of pandas.

• I have confirmed this bug exists on the main branch of pandas.

Reproducible Example

from io import BytesIO
import pandas

csv = b'a,b\n1,2\n3,4'
with BytesIO(csv) as f:
    it = pd.read_csv(
                f,
                nrows=1,
                iterator=True,
            )
    for df in it:
        pass

Behavior:

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
Cell In[82], line 11
      5 with BytesIO(csv) as f:
      6     it = pd.read_csv(
      7                 f,
      8                 nrows=1,
      9                 iterator=True,
     10             )
---> 11     for df in it:
     12         pass

File ~\AppData\Local\anaconda3\Lib\site-packages\pandas\io\parsers\readers.py:1843, in TextFileReader.__next__(self)
   1841 def __next__(self) -> DataFrame:
   1842     try:
-> 1843         return self.get_chunk()
   1844     except StopIteration:
   1845         self.close()

File ~\AppData\Local\anaconda3\Lib\site-packages\pandas\io\parsers\readers.py:1984, in TextFileReader.get_chunk(self, size)
   1982     if self._currow >= self.nrows:
   1983         raise StopIteration
-> 1984     size = min(size, self.nrows - self._currow)
   1985 return self.read(nrows=size)

TypeError: '<' not supported between instances of 'int' and 'NoneType'

### Issue Description

It seems that `read_csv` throws a `TypeError` when combining `nrows` and `iterable`.


My context: I want to convert a CSV to parquet. The CSV is larger than memory, so I want to use `iterator=True`. The CSV contains a footer. But since `skipfooter` is not supported for the fast engines (c or pyarrow), and `comment` can only be a single character, I want to instead indirectly skip the footer by using `nrows`. (I know in advance the number of rows.) My data contains `\r\n` line endings, although the error happens with normal `\n`.

### Expected Behavior

The script runs without error. `nrows` rows of data are returned (across one chunk in this small example). 

### Installed Versions

<details>
INSTALLED VERSIONS
------------------
commit                : d9cdd2ee5a58015ef6f4d15c7226110c9aab8140
python                : 3.11.9.final.0
python-bits           : 64
OS                    : Windows
OS-release            : 10
Version               : 10.0.19045
machine               : AMD64
processor             : Intel64 Family 6 Model 142 Stepping 12, GenuineIntel
byteorder             : little
LC_ALL                : None
LANG                  : None
LOCALE                : English_Australia.1252

pandas                : 2.2.2
numpy                 : 1.26.4
pytz                  : 2024.1
dateutil              : 2.9.0.post0
setuptools            : 69.5.1
pip                   : 24.0
Cython                : None
pytest                : 7.4.4
hypothesis            : None
sphinx                : 7.3.7
blosc                 : None
feather               : 0.4.1
xlsxwriter            : 3.2.0
lxml.etree            : 5.2.1
html5lib              : 1.1
pymysql               : None
psycopg2              : None
jinja2                : 3.1.4
IPython               : 8.25.0
pandas_datareader     : None
adbc-driver-postgresql: None
adbc-driver-sqlite    : None
bs4                   : 4.12.2
bottleneck            : 1.3.7
dataframe-api-compat  : None
fastparquet           : None
fsspec                : 2024.3.1
gcsfs                 : None
matplotlib            : 3.8.4
numba                 : 0.59.1
numexpr               : 2.8.7
odfpy                 : None
openpyxl              : 3.1.2
pandas_gbq            : None
pyarrow               : 14.0.2
pyreadstat            : None
python-calamine       : None
pyxlsb                : None
s3fs                  : 2024.3.1
scipy                 : 1.13.1
sqlalchemy            : 2.0.30
tables                : 3.9.2
tabulate              : 0.9.0
xarray                : 2023.6.0
xlrd                  : 2.0.1
zstandard             : 0.22.0
tzdata                : 2023.3
qtpy                  : 2.4.1
pyqt5                 : None
</details>

[mdavis-xyz]

The error does not occur if chunksize is specified. That's the None the error refers to.

So I'm guessing that the default value for chunksize is not applied if nrows is set.

The solution (workaround for user for now): specify chunksize.

The solution (for pandas developers):

• apply the default chunksize value in this case; or
• assert that chunksize is specified. Throw a more clear ValueError (or something else) to the user saying that chunksize must be specified in this case.

[Aloqeely]

Thanks for the report! I will submit a PR soon which will use your first solution (apply default chunksize)