Sign change when doing math gives invalid number

[michi12321]

Bug:

>>> d = tomlkit.parse('x=-3.1415')
>>> d['x'] *= -1
>>> print(tomlkit.dumps(d))

returns:

a=+3.1415

>>> d['x'] *= -1
>>> print(tomlkit.dumps(d))

returns:

a=--3.1415

Subsequent parsing raises tomlkit.exceptions.InvalidNumberError.

Of course there is an easy workaround using type conversion: d['x'] = float(d['x'])*-1.

[JamesParrott]

I'mm not sure where the "a" is coming from in your example when everything is done on the "x" key. Nor how it is possible to get Python to print a float as "--3.1415" at all.

Suffice to say I could not reproduce the output posted (on Windows 11, Python 3.11, Tomlkit 0.11.8):

>>> d=tomlkit.parse('x=-3.1415')
>>> d['x'] *= -1
>>> print(tomlkit.dumps(d))
x=3.1415
>>> d['x'] *= -1
>>> print(tomlkit.dumps(d))
x=-3.1415

Please provide a minimal reproducible example and details of the environment. Until then I suggest this issue be closed.

[michi12321]

Hi James, thanks for your time! The 'a' is of course supposed to be a 'x'...
I can confirm that this issue doesn't appear in tomlkit 0.11.8 .
I was using tomlkit 0.12 on different versions of python (3.11+3.12) and different OS (Win10, Linux)
Minimal reproducible example below:

>>> import tomlkit
>>> d = tomlkit.parse('x=-3.14')
>>> d['x'] *= -1
>>> print(tomlkit.dumps(d))
x=+3.14
>>> d['x'] *= -1
>>> print(tomlkit.dumps(d))
x=--3.14
>>> tomlkit.parse(tomlkit.dumps(d))
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/michi/.virtualenvs/tk/lib/python3.11/site-packages/tomlkit/api.py", line 86, in parse
    return Parser(string).parse()
           ^^^^^^^^^^^^^^^^^^^^^^
  File "/home/michi/.virtualenvs/tk/lib/python3.11/site-packages/tomlkit/parser.py", line 139, in parse
    item = self._parse_item()
           ^^^^^^^^^^^^^^^^^^
  File "/home/michi/.virtualenvs/tk/lib/python3.11/site-packages/tomlkit/parser.py", line 238, in _parse_item
    return self._parse_key_value(True)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/michi/.virtualenvs/tk/lib/python3.11/site-packages/tomlkit/parser.py", line 331, in _parse_key_value
    val = self._parse_value()
          ^^^^^^^^^^^^^^^^^^^
  File "/home/michi/.virtualenvs/tk/lib/python3.11/site-packages/tomlkit/parser.py", line 456, in _parse_value
    raise self.parse_error(InvalidNumberError)
tomlkit.exceptions.InvalidNumberError: Invalid number at line 1 col 8

[JamesParrott]

You're welcome. Sorry I thought it was Python producing the --, whereas it's in the string from tomlkit.dumps. I can reproduce it now:

Python 3.12.1 (tags/v3.12.1:2305ca5, Dec  7 2023, 22:03:25) [MSC v.1937 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import tomlkit
>>> d = tomlkit.parse('x=-3.14')
>>> d
{'x': -3.14}
>>> print(tomlkit.dumps(d))
x=-3.14
>>> d['x'] *= -1
>>> print(tomlkit.dumps(d))
x=+3.14
>>> d['x'] *= -1
>>> print(tomlkit.dumps(d))
x=--3.14
>>> tomlkit.__version__
'0.12.0'

Anyway, note that tomlkit.loads returns a tomlkit.toml_document.TOMLDocument, which has the same __repr__ as a dict but is at best, a subclass. A normal Python dict can be formed from its .items(). But tomlkit will still remember its starting state and render it as --1.

But you're quite right. Integer values in tables seem to cycle through +, +, +, -, ... when multiplied by -1 (i.e. not just +,-,+,-,...):

python -ic "import tomlkit as tk"
>>> d =  tk.parse('x=-3')
>>> for __ in range(12):
...   d['x'] *= -1; print(tk.dumps(d))
...
x=+3
x=--3
x=3
x=-3
x=+3
x=--3
x=3
x=-3
x=+3
x=--3
x=3
x=-3

And Float values can never be negative at all:

>>> d =  tk.parse('x=-3.14')
>>> for __ in range(6):
...   d['x'] *= -1; print(tk.dumps(d))
...
x=+3.14
x=--3.14
x=+3.14
x=--3.14
x=+3.14
x=--3.14