split silently returns wrong result for multi-character separators

[Miladkhoshdel]

Repository commit

791deb4

Python version (python --version)

3.14.4

Dependencies version (pip freeze)

pip==26.0.1

Expected behavior

In strings/split.py, the custom split function should not silently return the unsplit string when separator has multiple characters. It should raise a clear ValueError.

Actual behavior

File location

strings/split.py

Actual behavior

In strings/split.py, the custom split function compares each character in the input string with separator.

Because of that, a multi-character separator such as "--" is never matched:

split("a--b--c", separator="--")

[Miladkhoshdel]

I opened a PR for this here: #14655

[Pallavi-vi-1234]

Hi, I would like to work on this issue. Could you please assign it to me?

[Miladkhoshdel]

Hi, I would like to work on this issue. Could you please assign it to me?

I opened a pull request to fix it 19 days ago.

[kuishou68]

I have submitted a PR to fix this issue: #14751

The fix adds validation to raise a ValueError when the separator is not exactly one character, which matches the expected behavior described in this issue.

Closes #14649

[cclauss]

@Miladkhoshdel It could be quite useful to support multi-character separators.

The doctest should be:

    >>> split("--a--b--c--", separator="--")
    ['', 'a', 'b', 'c', '']