`pak::pkg_install(character())` triggers internal error

[HenningLorenzen-ext-bayer]

Preferably on a Linux machine, try

pak::pkg_install(character())

See also downstream comment on possibly related {pak} issue

> sessioninfo::session_info(pkgs = "pak")
─ Session info ─────────────────────────────────────────────────────────────────────────────
 setting  value
 version  R version 4.5.1 (2025-06-13)
 os       Ubuntu 22.04.5 LTS
 system   x86_64, linux-gnu
 ui       RStudio
 language (EN)
 collate  C.UTF-8
 ctype    C.UTF-8
 tz       Etc/UTC
 date     2025-06-27
 rstudio  2025.05.0+496.pro5 Mariposa Orchid (server)
 pandoc   2.9.2.1 @ /usr/bin/pandoc
 quarto   1.6.42 @ /usr/lib/rstudio-server/bin/quarto/bin/quarto

─ Packages ─────────────────────────────────────────────────────────────────────────────────
 package * version date (UTC) lib source
 pak       0.9.0   2025-05-27 [1] RSPM (R 4.5.0)

 [1] /home/[redacted]/R/x86_64-pc-linux-gnu-library/4.5
 [2] /opt/R/4.5.1/lib/R/library

────────────────────────────────────────────────────────────────────────────────────────────
> pak::pak_sitrep()
* pak version:
- 0.9.0
* Version information:
- pak platform: x86_64-pc-linux-gnu (current: x86_64-pc-linux-gnu, compatible)
- pak repository: - (local install?)
* Optional packages installed:
- pillar
* Library path:
- /home/[redacted]/R/x86_64-pc-linux-gnu-library/4.5
- /opt/R/4.5.1/lib/R/library
* pak is installed at /home/[redacted]/R/x86_64-pc-linux-gnu-library/4.5/pak.
* Dependency versions:
- callr      3.7.6 
- cli        3.6.5 
- curl       5.2.3 
- desc       1.4.3 
- filelock   1.0.3 
- jsonlite   2.0.0 
- keyring    1.4.0 
- lpSolve    5.6.23
- pkgbuild   1.4.8 
- pkgcache   2.2.4 
- pkgdepends 0.9.0 
- pkgsearch  3.1.5 
- processx   3.8.6 
- ps         1.9.1 
- R6         2.5.1 
- yaml       2.3.10
- zip        2.3.3 
* Dependencies can be loaded
> pak::pkg_install(character())
Error:                                  
! error in pak subprocess
Caused by error in `pkgplan_solve(self, private, match.arg(policy))`:
! Error in dependency solver, cannot solve installation.
ℹ Solver status: -1.
ℹ This is an internal error in pkgdepends, please report an issue at
  .
Type .Last.error to see the more details.

> .Last.error

Error: 
! error in pak subprocess
Caused by error in `pkgplan_solve(self, private, match.arg(policy))`:
! Error in dependency solver, cannot solve installation.
ℹ Solver status: -1.
ℹ This is an internal error in pkgdepends, please report an issue at
  .
---
Backtrace:
1. pak::pkg_install(character())
2. pak:::remote(function(...) get("pkg_install_make_plan", asNamespace("pak"))(...), …
3. err$throw(res$error)
---
Subprocess backtrace:
1. base::withCallingHandlers(cli_message = function(msg) { …
2. get("pkg_install_make_plan", asNamespace("pak"))(...)
3. prop$solve()
4. private$plan$solve(policy = private$policy)
5. pkgdepends:::pkgplan_solve(self, private, match.arg(policy))
6. base::throw(pkg_error("Error in dependency solver, cannot solve installation.", …
7. | base::signalCondition(cond)
8. global (function (e) …