Error when parsing strings containing digits and starting or ending with an 'e'

[HubertPalo]

🐛 Bug report

ArgumentParser fails to parse strings that contains digits and a starting or ending 'e'. For example:

• e5125
• e852343
• e96
• 812743e
• 7435e
• 913264e

To reproduce

from jsonargparse import ArgumentParser

parser = ArgumentParser(prog="app", description="Description for my app.")
parser.add_argument("--opt", type=str, default='asdasd', help="Test")
cfg = parser.parse_args(["--opt", "913264e"])
print(type(cfg.opt))

It returns the following error:

usage: app [-h] [--opt OPT]
error: Parser key "opt":
  could not convert string to float: '913264e'

Expected behavior

The code should not throw an exception and parse the value into a string

Environment

• jsonargparse version: 4.36.0
• Python version: 3.10.6
• How jsonargparse was installed: through 'pip install jsonargparse' and 'pip install jsonargparse --upgrade'
• OS: Ubuntu

[HubertPalo]

First, the logic of the load_basic function:

def load_basic(value):
    value = value.strip()
    if value == "true":
        return True
    if value == "false":
        return False
    if value == "null":
        return None
    if value.isdigit() or (value.startswith("-") and value[1:].isdigit()):
        return int(value)
    if value.replace(".", "", 1).replace("e", "", 1).replace("-", "", 2).isdigit() and ("e" in value or "." in value):
        return float(value)
    return not_loaded

The function considers as a float any string that comply with:

• After deleting one '.' or one '-' or one 'e', all left characters are digits.
  AND
• Contains at least one 'e' or at least one '.'

Unfortunately, following that logic results in the strings 'e7217418' and '12314e' being considered floats instead of strings.

To correct this, I propose two simple additional conditions: to check for initial or endings 'e':

def load_basic(value):
    value = value.strip()
    if value == "true":
        return True
    if value == "false":
        return False
    if value == "null":
        return None
    if value.isdigit() or (value.startswith("-") and value[1:].isdigit()):
        return int(value)
    if (
        not value.startswith("e")
        and not value.endswith("e")
        and value.replace(".", "", 1).replace("e", "", 1).replace("-", "", 2).isdigit()
        and ("e" in value or "." in value)
    ):
        return float(value)
    return not_loaded

Also an additional test:

def test_load_value_digits_and_e():
    with parser_context(load_value_mode="yaml"):
        assert "e123" == load_value("e123")
        assert "123e" == load_value("123e")

[mauvilsa]

Fixed by #673