Multi-Word Token with invalid field in an imported CoNLL-U giving a NumberFormatException

[khemarato]

Describe the bug
Importing a CoNLL-U file with a Multi-Word Token ID (e.g. "13-14") gives a NumberFormatException.

To Reproduce
Import a .conll document in CoNLL-U format with a MWT [ETA] and values for fields that should be blank

Expected behavior
[Edit] Give a "field should be blank" error

Screenshots

Please complete the following information:

• Version and build ID: 40.1 (2026-03-31 11:35:47, build b8aa303)
• OS: Linux
• Browser: Chrome

[khemarato]

In the UD Spec, see that the ID col can be an integer OR a range in the case of multiword tokens: https://universaldependencies.org/format.html

[reckart]

This file imports nicely into INCEpTION:

# text = vamos nos a el mar
1-2	vámonos	_	_	_	_	_	_	_	_
1	vamos	ir	_	_	_	_	_	_	_
2	nos	nosotros	_	_	_	_	_	_	_
3-4	al	_	_	_	_	_	_	_	_
3	a	a	_	_	_	_	_	_	_
4	el	el	_	_	_	_	_	_	_
5	mar	mar	_	_	_	_	_	_	_

Can you provide an example file to trigger the problem?

[khemarato]

Here's the file I was testing with: https://gist.github.com/khemarato/009ef0d08e8fca39eabb21bea715405d

[reckart]

As the spec says:

To accommodate the representation of both words and (multiword) tokens (see Tokenization and word segmentation), we adopt an extension of the original CoNLL-X token indexing scheme, where words are indexed with integers 1, 2, 3, …, while (multiword) tokens are indexed with integer ranges like 1-2 or 3-5. Lines representing such tokens are inserted before the first word in the range. These ranges must be nonempty and must not overlap. They have a FORM value – the string that occurs in the sentence – but have an underscore in all the remaining fields except MISC (because the token represents multiple words, each with its own lemma, part-of-speech tag, syntactic head, and so on).

However, in your sample, the multiword token does not have an underscore in all the remaining fields:

13-14	karerikuṭikāyaṃ	karerikuṭikā	_	_	Case=Loc|Gender=Fem|Number=Sing	12	appos	_	_

Hence, this is not valid CoNLL-U.

[khemarato]

Ah! Okay, thank you 😊 In that case, I guess a clearer error message would have helped me. Something like, Non-blank LEMMA unsupported for range ID