cabal repl other-package doesn't open repl

[robx]

Describe the bug
When I call cabal repl package-name for some dependency in the current project, cabal accepts the argument, builds it, and then just exits.

To Reproduce
Steps to reproduce the behavior:

$ cd Cabal
$ cabal v2-repl filepath
Resolving dependencies...
Up to date
$ echo $?
0

Expected behavior
I'd expect either an error telling me what I'm trying to do doesn't make sense, or a repl prompt.

System information

• Operating system: macos
• cabal 3.6.2.0 & recent HEAD, ghc 8.10.7

Additional context
What I was actually trying to do is bring an indirect dependency into scope. A repl within http-conduit which depends on http-client which pulls in network-uri, and I can't interact with the URIs I get out of some of the things I have in scope. Not sure cabal repl network-uri should have helped with that, or what would be the best way to achieve that.

[ptkato]

What happens if you try to use something like cabal repl --build-depends network-uri?

[robx]

What happens if you try to use something like cabal repl --build-depends network-uri?

Yeah, that works for what I was originally trying to do, thanks!

[Mikolaj]

So the request is to error out early and perhaps even suggest the --build-depends syntax?

[robx]

I don't know, I don't have a request as such. I don't know if there was ever any intended purpose behind supporting cabal repl package-name. If it's just accidental that this gets handled the way it does, then yes, erroring out and optionally recommending --build-depends seems like a sensible solution.

[Mikolaj]

Oh, I missed that cabal repl package-name (probably) doesn't have any use, even if package-name is the same package in which we reside. I wonder what happens if we are in a project with several packages. Does it then let you pick which package to repl?

[robx]

Yeah, looks like that's what it does; e.g. cabal repl cabal-install or cabal repl Cabal do useful things.

[Mikolaj]

Thanks for checking. In that case, I guess it would be useful to check early that a package with that name exists in current project, if not, explain and suggest --build-depends. Does it make sense?