handling of new blocks that aren't on a new line

[benlogan]

Describe the bug

V1 handled input files where the new blocks (indicated by @) aren't necessarily on a new line.
V2 attempts to ignore these, but instead get's into a real mess, because they end up being 'nested' within other entries. If they were properly ignored (i.e. parsed and dropped), then it would kind of be ok and consistent, but they make it into the raw data for each entry.
This leads to all sorts of problems. They will reappear, for example, when you write the library back out to a file later!
Very confusing.
IMHO, they should be treated as valid blocks and handled properly. I've tested a fix for this locally and it appears to work OK.

Reproducing

Version: latest

Code:

parse any file with inline new blocks, e.g.;
parsed_lib = bibtexparser.parse_file(filename)

Bibtex:

@article{KUEH2023S98,
title = {Myocardial Characterisation Using Delayed Dual-Energy Cardiac Computed Tomography},
journal = {Heart, Lung and Circulation},
volume = {32},
pages = {S98},
year = {2023},
note = {Abstracts for the Cardiac Society of Australia and New Zealand Annual Scientific Meeting (New Zealand) 2023, 15 - 17 June 2023, Auckland, New Zealand},
issn = {1443-9506},
doi = {https://doi.org/10.1016/j.hlc.2023.04.262},
url = {https://www.sciencedirect.com/science/article/pii/S1443950623004390},
author = {S.-H. Kueh and J. Benatar and R. Stewart}
}@INPROCEEDINGS{9837531,
  author={Hassan, Mona Bakri and Saeed, Rashid A. and Khalifa, Othman and Ali, Elmustafa Sayed and Mokhtar, Rania A. and Hashim, Aisha A.},
  booktitle={2022 IEEE 2nd International Maghreb Meeting of the Conference on Sciences and Techniques of Automatic Control and Computer Engineering (MI-STA)}, 
  title={Green Machine Learning for Green Cloud Energy Efficiency}, 
  year={2022},
  volume={},
  number={},
  pages={288-294},
  doi={10.1109/MI-STA54861.2022.9837531}}@ARTICLE{9372936,
  author={Hu, Ning and Tian, Zhihong and Du, Xiaojiang and Guizani, Nadra and Zhu, Zhihan},
  journal={IEEE Transactions on Green Communications and Networking}, 
  title={Deep-Green: A Dispersed Energy-Efficiency Computing Paradigm for Green Industrial IoT}, 
  year={2021},
  volume={5},
  number={2},
  pages={750-764},
  doi={10.1109/TGCN.2021.3064683}}@ARTICLE{5445167,
  author={Kumar, Karthik and Lu, Yung-Hsiang},
  journal={Computer}, 
  title={Cloud Computing for Mobile Users: Can Offloading Computation Save Energy?}, 
  year={2010},
  volume={43},
  number={4},
  pages={51-56},
  doi={10.1109/MC.2010.98}}

Workaround
Did you identify a workaround? Yes - I will send a pull request...

Remaining Questions (Optional)
Please tick all that apply:

• I would be willing to to contribute a PR to fix this issue.
• This issue is a blocker, I'd be greatful for an early fix.

[benlogan]

fixed via PR, I think - please check and merge...
(and thanks for this awesome library!)

[MiWeiss]

Hi

Thanks a lot for your bug report and also for opening the PR!

I can confirm that the library assumes that new entries start on a new line. I went through a range of standard bibtex documentation and - while they all seem to implicitly assume this - it does not seem to be stated anywhere explicetly, making this a valid bug. 🐛

Your PR still has breaking tests and I am afraid more changes would be necessary to implement the function correctly. Would you be able to dedicate more time to it? If not, I am greatful for a quick heads-up, allowing me to open this issue for other contributors.

[schnoddelbotz]

Hi

I just wanted to add that entries starting on a new line but have leading whitespace (before the @) are also (silently) ignored.
FWIW, bibtool ( https://github.com/ge-ne/bibtool ) accepts those entries.

[MiWeiss]

For reference, see also PR #412

[zepinglee]

The original BibTeX skips everything else until finding an @ sign as the next entry or command. It doesn't necessarily appear at a new line.

https://github.com/TeX-Live/texlive-source/blob/e48a783fdaff9b28797bfe95eee30c59bfca3d67/texk/web2c/bibtex.web#L5406-L5417

[MiWeiss]

Thanks @zepinglee for opening #416. I have assinged the issue to you.