kpsewhich cache causes "List or Blob required" error on completion

[user202729]

Description

Reproduce:

Put this into the kpsewhich.json cache file

{"inputenc.tex":"",
"ucs.sty":"/usr/share/texmf-dist/tex/latex/ucs/ucs.sty",
"geometry.tex":"",
"xparsex.cls":[["",
"/tmp"]],
"inputenc.sty":"/usr/share/texmf-dist/tex/latex/base/inputenc.sty",
"ifvtex.tex":"",
"keyval.tex":"/usr/share/texmf-dist/tex/generic/xkeyval/keyval.tex",
"hyperref.tex":"",
"geometry.sty":"/usr/share/texmf-dist/tex/latex/geometry/geometry.sty",
"iftex.tex":"",
"expl3.tex":"",
"#1.cls":"",
"ifvtex.sty":"/usr/share/texmf-dist/tex/generic/iftex/ifvtex.sty",
"hyperref.sty":"/usr/share/texmf-dist/tex/latex/hyperref/hyperref.sty",
"#1.def":"",
"iftex.sty":"/usr/share/texmf-dist/tex/generic/iftex/iftex.sty",
"amsmath.tex":"",
"kvsetkeys.tex":"",
"shellesc.sty":"/usr/share/texmf-dist/tex/latex/tools/shellesc.sty",
"pdftexcmds.tex":"",
"xparse.tex":"",
"amsmath.sty":"/usr/share/texmf-dist/tex/latex/amsmath/amsmath.sty",
"xparsex.tex":[["",
"/tmp"]],
"kvsetkeys.sty":"/usr/share/texmf-dist/tex/generic/kvsetkeys/kvsetkeys.sty",
"shellesc.tex":"",
"ucshyper.tex":"",
"atbegshi.tex":"",
"pdftexcmds.sty":"/usr/share/texmf-dist/tex/generic/pdftexcmds/pdftexcmds.sty",
"xparse.sty":"/usr/share/texmf-dist/tex/latex/l3packages/xparse/xparse.sty",
"xparsex.sty":[["",
"/tmp"]],
"ucshyper.sty":"/usr/share/texmf-dist/tex/latex/ucs/ucshyper.sty",
"atbegshi.sty":"/usr/share/texmf-dist/tex/generic/atbegshi/atbegshi.sty",
"expl3.sty":"/usr/share/texmf-dist/tex/latex/l3kernel/expl3.sty"}

is
Open a TeX file with this content

\usepackage{xparse}
\a

Put the cursor after the last a then press ctrl+N.

Error:

Scanning tags.
Error detected while processing function vimtex#include#expr[41]..<SNR>108_search_candidates_kpsewhich[22]..vimtex#kpsewhich#find:
line   27:
E897: List or Blob required
Press ENTER or type command to continue

The problem does not happen without the cache, but because VimTeX (presumably) generate that cache, it's still the plugin's bug?

Steps to reproduce

No response

Expected behavior

No response

Actual behavior

No response

Do you use a latexmkrc file?

Yes

VimtexInfo

System info
  OS: Arch Linux
  Vim version: VIM 8.2 (1-2891)
  Has clientserver: true
  Servername: undefined (vim started without --servername)

VimTeX project: d
  base: d.tex
  root: /tmp
  tex: /tmp/d.tex
  main parser: current file
  document class: 
  packages: xparse
  compiler: latexmk
    engine: -pdf
    options:
      -verbose
      -file-line-error
      -synctex=1
      -latexoption=--shell-escape
      -interaction=nonstopmode
    build_dir: /tmp/.vimtex_build_dir/
    callback: 1
    continuous: 1
    executable: latexmk
  viewer: General
  qf method: LaTeX logfile

[lervag]

Thanks, I'll see if I can improve the error handling here. But the simple solution would be to clear the cache with :VimtexClearCache kpsewhich. After doing that, everything should work well again.

[user202729]

The problem is that why the cache get into the state in the first place (surely I don't manually modify the file)

[lervag]

The cache got in that state because I made a change to the underlying code that changed how the cache was used. I thought I also added necessary error catching with messages to help people clear the cache if necessary, but I'm sorry to say I've missed something.

But you should not get invalid cache after clearing it.

[user202729]

(it's okay. I just didn't understand what was going on)

A possible idea to avoid such cases in the future is to write a version number in the cache file, then delete the cache when there's an incompatible change, but it isn't really possible to retroactively apply that now

(besides, the format doesn't change that frequently)

[lervag]

A possible idea to avoid such cases in the future is to write a version number in the cache file, then delete the cache when there's an incompatible change, but it isn't really possible to retroactively apply that now

Yes, that's a good idea. I thought of it before, but never found a good way to get the current vimtex git commit hash reliably. But that's not necessary, I can just use a cache specific version that I manually bump if I make a change to the cache.

I'll update and push. Thanks for the suggestion!