`local_install_deps` can't solve `<=` or `==` (or `@`) versions of DESCRIPTION packages that are not the latest

[notPlancha]

I'm trying to use pak to share dependencies in a project, but if a different version is installed pak can install a different version (through pkg_install), but can't install it with local_install_deps.

Example: DESCRIPTION:

Package: teste
Title: Teste
Version: 1.0
Depends:
  R (>= 4.3.0)
Imports:
  cowsay (== 0.8.2)

> library(pak)
> cache_clean()
> pkg_install("cowsay@0.9.0")
✔ Loading metadata database ... done

→ Will install 1 package.
→ Will download 1 CRAN package (402.58 kB).
+ cowsay   0.9.0 [dl] (402.58 kB)
ℹ Getting 1 pkg (402.58 kB)
✔ Got cowsay 0.9.0 (i386+x86_64-w64-mingw32) (402.79 kB)
✔ Downloaded 1 package (402.79 kB) in 855ms
✔ Installed cowsay 0.9.0  (75ms)
✔ 1 pkg + 3 deps: kept 3, added 1, dld 1 (402.79 kB)[4.6s]

> local_install_deps()
Error:
! error in pak subprocess
Caused by error:
! Could not solve package dependencies:
* deps::C:/Users/Plancha/Desktop/erro_do_pak: Can't install dependency cowsay (== 0.8.2)
Type .Last.error to see the more details.
> pkg_install("cowsay@0.8.2")
→ Will update 1 package.
→ Will download 1 package with unknown size.
+ cowsay 0.9.0 → 0.8.2 [bld][dl]
? Do you want to continue (Y/n) Y
ℹ Getting 1 pkg with unknown size
✔ Got cowsay 0.8.2 (source) (576.88 kB)
✔ Downloaded 1 package (576.88 kB) in 156ms
ℹ Building cowsay 0.8.2
✔ Built cowsay 0.8.2 (1.3s)
✔ Installed cowsay 0.8.2  (79ms)
✔ 1 pkg + 3 deps: kept 3, upd 1, dld 1 (576.88 kB) [13.6s]
> cowsay::say()
 --------------
Hello world!
 --------------
    \
      \
        \
            |\___/|
          ==) ^Y^ (==
            \  ^  /
             )=*=(
            /     \
            |     |
           /| | | |\
           \| | |_|/\
      jgs  //_// ___/
               \_)
> local_install_deps()
✔ Loading metadata database ... done

→ The package (0 B) is cached.
ℹ No downloads are needed
✔ 4 deps: kept 3 [4.7s]
> .Last.error
Registered S3 methods overwritten by 'callr':
  method                    from
  format.callr_status_error
  print.callr_status_error
<callr_error/rlib_error_3_0/rlib_error/error>
Error:
! error in pak subprocess
Caused by error:
! Could not solve package dependencies:
* deps::C:/Users/Plancha/Desktop/erro_do_pak: Can't install dependency cowsay (== 0.8.2)
---
Backtrace:
1. pak::pak()
2. pak::local_install_dev_deps(...)
3. pak:::remote(function(...) { …
4. err$throw(res$error)
---
Subprocess backtrace:
1. base::withCallingHandlers(cli_message = function(msg) { …
2. get("local_install_dev_deps_make_plan", asNamespace("pak"))(...)
3. prop$stop_for_solution_error()
4. private$plan$stop_for_solve_error()
5. pkgdepends:::pkgplan_stop_for_solve_error(self, private)
6. base::throw(new_error("Could not solve package dependencies:\n", msg, …
7. | base::signalCondition(cond)
8. global (function (e) …
> pak_sitrep()
* pak version:
- 0.7.0
* Version information:
- pak platform: x86_64-w64-mingw32 (current: x86_64-w64-mingw32, compatible)
- pak repository: - (local install?)
* Optional packages installed:
- pillar
* Library path:
- C:/Users/Plancha/AppData/Local/R/win-library/4.3
- C:/Program Files/R/R-4.3.2/library
* pak is installed at C:/Users/Plancha/AppData/Local/R/win-library/4.3/pak.
* Dependency versions:
- callr       3.7.3
- cli         3.6.1
- crayon      1.5.2
- curl        5.1.0
- desc        1.4.2
- distro      0.1.0
- filelock    1.0.2
- glue        1.6.2
- jsonlite    1.8.7
- lpSolve     5.6.19
- parsedate   1.3.1
- pkgbuild    1.4.2
- pkgcache    2.2.0.1
- pkgdepends  0.7.0
- pkgsearch   3.1.2
- prettyunits 1.2.0
- processx    3.8.2
- ps          1.7.5
- R6          2.5.1
- rappdirs    0.3.3
- rprojroot   2.0.4
- zip         2.3.0
* Dependencies can be loaded

Big things but that's mostly because I wanted to include everything and pak is quite verbose, here's all the command I ran

library(pak)
cache_clean()
pkg_install("cowsay@0.9.0") # installs
cowsay::say() # runs
local_install_deps() # error
pkg_install("cowsay@0.8.2") # installs
local_install_deps() # runs fine
pak_sitrep()
.Last.error # the error from local_install_deps

[gaborcsardi]

CRAN package metadata only contains the latest versions of packages, so if you have a <= or == version requirement, that only works in practice if you also allow the latest version in the CRAN(-like) repository.

This said, we could treat pkg (== ver) as pkg@ver and then == could work.

[notPlancha]

Oh yeah that's true, I didn't even notice that local_install_deps won't install even if another version isn't installed. I'll update the title