cabal-helper can't install Cabal-3.0.0.0 at runtime in windows

[jneira]

• Testing @fendor hie branch that uses cabal-helper master with hie-bios: https://github.com/fendor/haskell-ide-engine/tree/cabal-helper-helper (pr Use cabal-helper 1.0 mpickering/haskell-ide-engine#26)
• In windows 7
• Log with CABAL_HELPER_DEBUG=1:

D:\bin\Programs\stack\x86_64-windows\ghc-8.6.5\bin\ghc.exe --numeric-version
=> 8.6.5

cabal --numeric-version
=> 3.0.0.0

using helper compiled with Cabal from v2-build package-env C:\Users\user\Local Settings\Cache\cabal-helper\ghc-8.6.5.package-envs\Cabal-3.0.0.0.package-env
helper exe does not exist, compiling C:\Users\user\Local Settings\Cache\cabal-helper\cabal-helper-1.0.0.0--Cabal-3.0.0.0--c82cca47f9974858fe3c009873651f1e71ad14c20be7c4b4932a9ed554ec09d2.build\cabal-helper
cabal-helper: Installing a private copy of Cabal because we couldn't
find the right version anywhere on your system. You can set the environment
variable CABAL_HELPER_DEBUG=1 to see where we searched.

Note that this installation might take a little while but it will only
happen once per Cabal library version used in your build-plans.

If you want to avoid this automatic installation altogether install
version 3.0.0.0 of the Cabal library manually, either using cabal or your
system package manager. With cabal you can use the following command:
    $ cabal install Cabal --constraint "Cabal == 3.0.0.0"

FYI the build products and cabal-helper executable cache are all in the
following directory, you can simply delete it if you think something
is broken :
    C:\Users\user\Local Settings\Cache\cabal-helper
Please do report any problems you encounter.

Installing Cabal 3.0.0.0 ...
cabal --numeric-version
=> 3.0.0.0

cd C:\TEMP\; cabal --no-require-sandbox v2-install --with-compiler=D:\bin\Programs\stack\x86_64-windows\ghc-8.6.5\bin\ghc.exe --with-hc-pkg=D:\bin\Programs\stack\x86_64-windows\ghc-8.6.5\bin\ghc-pkg.exe '--package-env=C:\Users\user\Local Settings\Cache\cabal-helper\ghc-8.6.5.package-envs\Cabal-3.0.0.0.package-env' --lib Cabal-3.0.0.0
Resolving dependencies...
Up to date
Distribution\Simple\GHC.hs:1959:5-56: Non-exhaustive patterns in Just ghcPkgProg

• No C:\Users\user\Local Settings\Cache\cabal-helper is even created (and if it exists it doesnt create ghc-8.6.5.package-envs inside)

[jneira]

With cabal-install-2.4.1.0 in $PATH no private installation of Cabal is triggered and C:\Users\user\Local Settings\Cache\cabal-helper is not created (although the Cabal version installed globally in ghc-8.6.5 is Cabal-2.4.0.1)

I had a previous backup of C:\Users\user\Local Settings\Cache\cabal-helper with ghc-8.6.5.package-envs\Cabal-2.4.1.0.package-env and cabal-helper-1.0.0.0--Cabal-2.4.1.0-hash.build, but no idea how was created.

The contents of ghc-8.6.5.package-envs\Cabal-2.4.1.0.package-env is:

clear-package-db
global-package-db
package-db C:\Users\user\AppData\Roaming\cabal\store\ghc-8.6.5\package.db
package-id ghc-8.6.5
package-id bytestring-0.10.8.2
package-id base-4.12.0.0
package-id time-1.8.0.2
package-id hpc-0.6.0.3
package-id filepath-1.4.2.1
package-id process-1.6.5.0
package-id array-0.5.3.0
package-id integer-gmp-1.0.2.0
package-id containers-0.6.0.1
package-id ghc-boot-8.6.5
package-id binary-0.8.6.0
package-id ghc-prim-0.5.3
package-id ghci-8.6.5
package-id rts
package-id transformers-0.5.6.2
package-id deepseq-1.4.4.0
package-id ghc-boot-th-8.6.5
package-id pretty-1.1.3.6
package-id template-haskell-2.14.0.0
package-id directory-1.3.3.0
package-id text-1.2.3.1
package-id Cabal-2.4.1.0-402b1cba79c424853de8a789c317a675fe742791

but C:\Users\user\AppData\Roaming\cabal\store\ghc-8.6.5\package.db doesn't exist in my system cause i am setting store-dir: D:\csd to avoid max path issues.

[DanielG]

Can you run the cabal v2-install command by hand while adding -v3?

[jneira]

The last output executing the command is:

Warning: Package db
C:\Users\user\AppData\Roaming\cabal\store\ghc-8.6.5\package.db does not exist
yet
Distribution\Simple\GHC.hs:1959:5-56: Non-exhaustive patterns in Just ghcPkgProg

But i had to replace '--package-env=C:\Users\user\Local Settings\Cache\cabal-helper\ghc-8.6.5.package-envs\Cabal-3.0.0.0.package-env'with "--package-env=C:\Users\user\Local Settings\Cache\cabal-helper\ghc-8.6.5.package-envs\Cabal-3.0.0.0.package-env" (note the double quotes)

[jneira]

Thanks to @DanielG help we've founf that i was using a cabal-install-3.0.0.0 version without the fix for haskell/cabal#5941, Downloading the official released version from https://www.haskell.org/cabal/download.html fixed it.

I'll promise next time i will remember to wipe out testing versions!