What are .did filenames conventions?

[vporton]

Weirdly, I have:

$ ls /home/porton/Projects/zondirectory2/.dfx/local/lsp/
3btem-pg5o6-wliii-ntu2q.did      by6od-j4aaa-aaaaa-qaadq-cai.did  gapbg-upjh7-l6brf-pjxwq.did  mgiih-uki2t-dxtv4-fdsea.did  shsdd-krnhk-7n5f6-5wfrq.did
752b2-qspfd-kywhm-syrfq.did      d6uyq-ku74l-h7enm-r5cnq.did      hmu2w-vzr6l-xxeow-bdcfa.did  ngmos-qym5g-w4zpj-tageq.did  w5bet-5pk4w-bjid3-cphhq.did
b77ix-eeaaa-aaaaa-qaada-cai.did  ejulz-72kru-roj64-l4otq.did      kiati-2bimr-5qvvh-bg6ua.did  pp522-4cdua-rd6hp-iwjwa.did

The weird thing is that two files (b77ix-eeaaa-aaaaa-qaada-cai.did and by6od-j4aaa-aaaaa-qaadq-cai.did) have longer filenames than the rest. It also appears that these two files have actual principals as the base names unlike the rest files.

Please, explain the naming conventions for .did files. What a filename can be, if it is not a principal (like most of the above files, apparently). I participate in development of DFX and need to understand this well.

Also, I should note that I use a modified DFX: https://github.com/vporton/sdk in which I am doing development.

[vporton]

These "shortened principals" seems to be a bug that is hard to reprise. And I don't know which versions are vulnerable to it.

[vporton]

I reproduced this bug in DFX 0.19.0: #3733