Bug report

Bug description:

Hi!

When calling the 'open' function with a path that contains invalid symbols inside the file name, e.g. a colon, the function will truncate that path, proceed to create the file, but not write any contents to it.
What I expected to happen is that an exception is being raised and no file is created.

I don't know if this is intended behaviour and I couldn't find something about this in neither the documentation (https://docs.python.org/3/library/functions.html#open) or the PEP website.

Can somebody confirm/deny that this is a bug?

Minimal reproducible example

defmain():fromosimportpathbasePath=path.dirname(__file__)filePath=path.join(basePath,"invalid:symbols.txt")fileContent="hello world that is probably not being written to file"withopen(filePath,"w",encoding="utf-8")asfile:file.write(fileContent)if__name__=="__main__":main()

The above snippet results in an empty file calledinvalid.txt to be created.

I hope that this isn't a duplicate, I tried searching for a similar unclosed issue but couldn't find any.
In case this is expected behaviour, it would be great if it'd be mentioned in the documentation. 🥰

EDIT: Fixed the wrong file name, sorry

CPython versions tested on:

3.12, 3.13

Operating systems tested on:

Windows