lintr hangs on openxlsx

[JanMarvin]

Hello,
in one of the many packages for which I use lintr, lintr started hanging after the last version 3.0. This can be reproduced both locally (R 4.2.1 on Mac and lintrs HEAD) and in the Github action.

lintr::lint_package() hangs on openxlsx. This can be seen with the latest CRAN release of openxlsx and also in the development branch. While the openxlsx code is known to be a mess, lintr did not hang before its release 3.0. Unfortunately there is not much else I can report, there is no verbose option that I am aware of. I tried to disable the linter mentioned in #1427 but that did not help. Let me know if you need anything else.

Thank you for the time you have invested in the development and maintenance of lintr!

[MichaelChirico]

Thanks for the report! I'm definitely reproducing strange slowness at current HEAD on openxlsx.

To debug, I start with:

trace(lintr::lint, at=1, quote(message(filename)))
lintr::lint_package()

this shows me what files are going slowly, and where it gets stuck.

R/wrappers.R is quite slow -- perhaps not surprising as it clocks in at 4K lines.

But where it really gets stuck is vignettes/Intro.Rmd. This is strange because the file is not very large.

It looks like get_source_expressions() is choking on that file; investigating why.

[MichaelChirico]

OK, the issue is that there's a syntax error in the vignette:

ycphs/openxlsx#365

This is hidden because eval=FALSE in all the chunks. Maybe we should re-open #581?

It's not clear we're supposed to lint in chunks where eval=FALSE in the first place. But also, we shouldn't get stuck in an infinite loop in edge cases like this.

[JanMarvin]

Thanks for the explanation and the successful bug hunt!