cabal build ./pkgfoo doesn't work

[andreabedini]

Describe the bug

Hi Cabal maintainers, thank you for your work.

Accorting to the documentation provided by --help, I can tell cabal to build a package held in a specific directory.

$ cabal build --help
[snip]
Examples:
  cabal build
    Build the package in the current directory or all packages in the project
  cabal build pkgname
    Build the package named pkgname in the project
  cabal build ./pkgfoo
    Build the package in the ./pkgfoo directory

But this doesn't seem to work. See below for reproducible steps.

To Reproduce
Steps to reproduce the behavior:

$ mkdir cabal-build-pkgfoo-test
$ cd cabal-build-pkgfoo-test
$ cabal init --minimal --non-interactive

Guessing dependencies...

Generating LICENSE...
Warning: unknown license type, you must put a copy in LICENSE yourself.
Generating CHANGELOG.md...
Generating app/Main.hs...
Generating cabal-build-pkgfoo-test.cabal...

Warning: no synopsis given. You should edit the .cabal file and add one.
You may want to edit the .cabal file and add a Description field.

$ cd ..
$ cabal v2-build ./cabal-build-pkgfoo-test
No cabal.project file or cabal file matching the default glob './*.cabal' was found.
Please create a package description file <pkgname>.cabal or a cabal.project file referencing the packages you want to build.

Expected behavior

I expect the package in ./cabal-build-pkgfoo-test to be built. Likely the equivalent of cd ./cabal-build-pkgfoo-test && cabal v2-build && cd ...

System information

• macOS Catalina, 10.15.7
• cabal-install version 3.4.0.0 (compiled using version 3.4.0.0 of the Cabal library)
• ghc version 8.10.4

[fgaz]

Since something similar also happened in #7321 (comment) I suspect this is a regression. Could you check whether this also happened on 3.2?

[andreabedini]

Thanks for looking at it @fgaz, I'll try with 3.2 and report back

[andreabedini]

@fgaz

I can reproduce with 3.2 following the same instructions as above

$ cabal-3.2.0.0 v2-build ./cabal-build-pkgfoo-test
No cabal.project file or cabal file matching the default glob './*.cabal' was found.
Please create a package description file <pkgname>.cabal or a cabal.project file referencing the packages you want to build.

(now on ubuntu 20.04.2, cabal 3.2.0.0, ghc 8.10.4)