pkgdown::build_reference() fails on exported 'matches' function

[gladkia]

Hi,

Overview

It seems that pkgdown::build_reference() fails if the exported function is named 'matches'.

Such function can be e.g. found in testthat package:

testthat::matches
function(regexp, all = TRUE, ...) {
warning(
"matches() is deprecated. Please use expect_match() instead.",
call. = FALSE
)
function(x) expect_match(x, regexp, all = all, ...)
}
<environment: namespace:testthat>

How to reproduce

Add matches to references in _pkgdown.yml:

gladkia@gladkia-UHMD6M testthat % git diff
diff --git a/_pkgdown.yml b/_pkgdown.yml
index 209eea3d..62abeb34 100644
--- a/_pkgdown.yml
+++ b/_pkgdown.yml
@@ -53,6 +53,7 @@ reference:
   - skip
   - teardown_env
   - set_state_inspector
+  - matches
 
 - title: Run tests
   contents:

Then run:

> pkgdown::init_site()
> pkgdown::build_reference()

Observed error:

-- Building function reference -------------------------------------------------------------------------------------------------------------------------------------
Error in `map2()`:
ℹ In index: 6.
Caused by error in `purrr::map()`:
ℹ In index: 5.
Caused by error:
! In '_pkgdown.yml', topic must be a known topic name or alias
✖ Not 'matches'
Run `rlang::last_trace()` to see where the error occurred.

Context

Please see more detailed context here.

[dmurdoch]

I see the same error. It looks like the problem is with the YAML parser, because a workaround is to include that topic using

- contents:
  - matches("^matches$")

and the same problem happens if you have a function named starts_with, or the other pattern names: ends_with, has_keyword, has_concept, lacks_concepts.

[dmurdoch]

The problem appears to be happening here:

https://github.com/r-lib/pkgdown/blame/3979e7c0afbba4503248dc8a6d04fe0a2e03f26f/R/topics.R#L136-L142

The code has already put the aliases as entries in env, but it also put the selector functions matches(), starts_with() etc. into the same environment. I think the solution is to use two separate environments for these. I'll see if I can put together a PR.