cipher-aes128:setup.Cabal-3.8.0.20220526/installed-3.8.0.20220526 (conflict: cipher-aes128 => cipher-aes128:setup.Cabal>=1.10 && <3.7)

[exarkun]

Describe the bug

When attempting to build https://whetstone.private.storage/privatestorage/tahoe-chk (be0695ac38d8c1c623907f60b883a547c9d743e4) using ghc 9.2 or 9.4 and ghc-wasm-meta I encountered the following build error:

❯ cabal build --allow-newer=base  --allow-newer=text --disable-tests                                                                                                                                                                             [134/406]
Resolving dependencies...                                                                                                                                                                                                                                 
Error: cabal: Could not resolve dependencies:                                                                                                                                                                                                             
[__0] trying: tahoe-chk-0.1.0.2 (user goal)                                                                                                                                                                                                               
[__1] trying: cipher-aes128-0.7.0.6 (dependency of tahoe-chk)                                                                                                                                                                                             
[__2] next goal: cipher-aes128:setup.Cabal (dependency of cipher-aes128)                                                                                                                                                                                  
[__2] rejecting:                                                                                                                                                                                                                                          
cipher-aes128:setup.Cabal-3.8.0.20220526/installed-3.8.0.20220526 (conflict:                                                                                                                                                                              
cipher-aes128 => cipher-aes128:setup.Cabal>=1.10 && <3.7)                                                                                                                                                                                                 
[__2] skipping: cipher-aes128:setup.Cabal-3.10.1.0,                                                                                                                               
cipher-aes128:setup.Cabal-3.8.1.0 (has the same characteristics that caused                                                                                                       
the previous version to fail: excluded by constraint '>=1.10 && <3.7' from                                                                                                        
'cipher-aes128')                                                                                                                                                                  
[__2] rejecting: cipher-aes128:setup.Cabal-3.6.3.0,                                                                                                                               
cipher-aes128:setup.Cabal-3.6.2.0, cipher-aes128:setup.Cabal-3.6.1.0,                                                                                                             
cipher-aes128:setup.Cabal-3.6.0.0, cipher-aes128:setup.Cabal-3.4.1.0,                                                                                                             
cipher-aes128:setup.Cabal-3.4.0.0, cipher-aes128:setup.Cabal-3.2.1.0,                                                                                                             
cipher-aes128:setup.Cabal-3.2.0.0, cipher-aes128:setup.Cabal-3.0.2.0,                                                                                                             
cipher-aes128:setup.Cabal-3.0.1.0, cipher-aes128:setup.Cabal-3.0.0.0,                                                                                                             
cipher-aes128:setup.Cabal-2.4.1.0, cipher-aes128:setup.Cabal-2.4.0.1,                                                                                                             
cipher-aes128:setup.Cabal-2.4.0.0, cipher-aes128:setup.Cabal-2.2.0.1,                                                                                                             
cipher-aes128:setup.Cabal-2.2.0.0, cipher-aes128:setup.Cabal-2.0.1.1,                                                                                                             
cipher-aes128:setup.Cabal-2.0.1.0, cipher-aes128:setup.Cabal-2.0.0.2,  
cipher-aes128:setup.Cabal-1.24.2.0, cipher-aes128:setup.Cabal-1.24.0.0,
cipher-aes128:setup.Cabal-1.22.8.0, cipher-aes128:setup.Cabal-1.22.7.0,
cipher-aes128:setup.Cabal-1.22.6.0, cipher-aes128:setup.Cabal-1.22.5.0,                                                                                                           
cipher-aes128:setup.Cabal-1.22.4.0, cipher-aes128:setup.Cabal-1.22.3.0,                  
cipher-aes128:setup.Cabal-1.22.2.0, cipher-aes128:setup.Cabal-1.22.1.1,                  
cipher-aes128:setup.Cabal-1.22.1.0, cipher-aes128:setup.Cabal-1.22.0.0,
cipher-aes128:setup.Cabal-1.20.0.4, cipher-aes128:setup.Cabal-1.20.0.3,                  
cipher-aes128:setup.Cabal-1.20.0.2, cipher-aes128:setup.Cabal-1.20.0.1,
cipher-aes128:setup.Cabal-1.20.0.0, cipher-aes128:setup.Cabal-1.18.1.7,      
cipher-aes128:setup.Cabal-1.18.1.6, cipher-aes128:setup.Cabal-1.18.1.5,                  
cipher-aes128:setup.Cabal-1.18.1.4, cipher-aes128:setup.Cabal-1.18.1.3, 
cipher-aes128:setup.Cabal-1.18.1.2, cipher-aes128:setup.Cabal-1.18.1.1,   
cipher-aes128:setup.Cabal-1.18.1, cipher-aes128:setup.Cabal-1.18.0,                                                                                                               
cipher-aes128:setup.Cabal-1.16.0.3, cipher-aes128:setup.Cabal-1.16.0.2,                                                                                                           
cipher-aes128:setup.Cabal-1.16.0.1, cipher-aes128:setup.Cabal-1.16.0,                                                                                                             
cipher-aes128:setup.Cabal-1.14.0, cipher-aes128:setup.Cabal-1.12.0,                      
cipher-aes128:setup.Cabal-1.10.2.0, cipher-aes128:setup.Cabal-1.10.1.0,                                                                                                           
cipher-aes128:setup.Cabal-1.10.0.0, cipher-aes128:setup.Cabal-1.8.0.6,                                                                                                            
cipher-aes128:setup.Cabal-1.8.0.4, cipher-aes128:setup.Cabal-1.8.0.2,                    
cipher-aes128:setup.Cabal-1.6.0.3, cipher-aes128:setup.Cabal-1.6.0.2,                    
cipher-aes128:setup.Cabal-1.6.0.1, cipher-aes128:setup.Cabal-1.4.0.2,                    
cipher-aes128:setup.Cabal-1.4.0.1, cipher-aes128:setup.Cabal-1.4.0.0,                    
cipher-aes128:setup.Cabal-1.2.4.0, cipher-aes128:setup.Cabal-1.2.3.0,                
cipher-aes128:setup.Cabal-1.2.2.0, cipher-aes128:setup.Cabal-1.2.1,                      
cipher-aes128:setup.Cabal-1.1.6, cipher-aes128:setup.Cabal-1.24.1.0  
(constraint from minimum version of Cabal used by Setup.hs requires >=3.8)               
[__2] fail (backjumping, conflict set: cipher-aes128,                                    
cipher-aes128:setup.Cabal)                                                               
After searching the rest of the dependency tree exhaustively, these were the             
goals I've had most trouble fulfilling: cipher-aes128:setup.Cabal, tahoe-chk,
cipher-aes128                                                                            

To Reproduce
Steps to reproduce the behavior:

• Get ghc (I got mine from nixos 23.05, haskell.compiler.ghc941)
• Get ghc-wasm-meta (I got mine with nix shell https://gitlab.haskell.org/ghc/ghc-wasm-meta/-/archive/master/ghc-wasm-meta-master.tar.gz, rev bd1b3778e8100a5e8c89962903a8c2ae3ff5c611)
• Make a project that depends on cipher-aes12, (eg, like tahoe-chk does)
• cabal build (or cabal build --allow-newer=base --allow-newer=text --disable-tests if trying with tahoe-chk)

Expected behavior

A successful build!

System information

• Operating system - NixOS 23.05
• cabal 3.10.1.0 (see above)
• ghc.9.4.1 (see above)

[Mikolaj]

Ping @mpickering @sheaf @dcoutts: that's the ticket I was talking about.

@exarkun: let us know if the solution @fgaz found (the one related to

cabal/cabal-install/src/Distribution/Client/ProjectPlanning.hs

Lines 1393 to 1425 in d363088

	-- While we can talk to older Cabal versions (we need to be able to
	-- do so for custom Setup scripts that require older Cabal lib
	-- versions), we have problems talking to some older versions that
	-- don't support certain features.
	--
	-- For example, Cabal-1.16 and older do not know about build targets.
	-- Even worse, 1.18 and older only supported the --constraint flag
	-- with source package ids, not --dependency with installed package
	-- ids. That is bad because we cannot reliably select the right
	-- dependencies in the presence of multiple instances (i.e. the
	-- store). See issue #3932. So we require Cabal 1.20 as a minimum.
	--
	-- Moreover, lib:Cabal generally only supports the interface of
	-- current and past compilers; in fact recent lib:Cabal versions
	-- will warn when they encounter a too new or unknown GHC compiler
	-- version (c.f. #415). To avoid running into unsupported
	-- configurations we encode the compatibility matrix as lower
	-- bounds on lib:Cabal here (effectively corresponding to the
	-- respective major Cabal version bundled with the respective GHC
	-- release).
	--
	-- GHC 9.2 needs Cabal >= 3.6
	-- GHC 9.0 needs Cabal >= 3.4
	-- GHC 8.10 needs Cabal >= 3.2
	-- GHC 8.8 needs Cabal >= 3.0
	-- GHC 8.6 needs Cabal >= 2.4
	-- GHC 8.4 needs Cabal >= 2.2
	-- GHC 8.2 needs Cabal >= 2.0
	-- GHC 8.0 needs Cabal >= 1.24
	-- GHC 7.10 needs Cabal >= 1.22
	--
	-- (NB: we don't need to consider older GHCs as Cabal >= 1.20 is
	-- the absolute lower bound)

) works for you (using and older cabal-install binary is it, I guess?).

Let me cite a part of the discussion from #7088

[mpickering]

It seems unlikely this will work in any case as custom Setup.hs don't work with cross-compilers?

[fgaz]

let us know if the solution @fgaz found works for you (using and older cabal-install binary is it, I guess?)

The solution would be to downgrade GHC. Quoting the comment:

To avoid running into unsupported configurations we encode the compatibility matrix as lower bounds on lib:Cabal here (effectively corresponding to the respective major Cabal version bundled with the respective GHC release).

So cabal-install imposes a Cabal bound depending on the GHC version.

You could also attempt to relax the upper bound on Cabal with --allow-newer=Cabal.

If downgrading GHC is not possible and you confirmed that relaxing the upper bound breaks the package, in theory downgrading cabal can also work since older cabal-installs don't know about newer GHCs, but the result can be unpredictable.

---

The error message can definitely be improved, by explaining what "minimum version of Cabal used by Setup.hs" is and why it's there

[andreabedini]

Note that this can be reproduced without ghc-wasm-meta:

$ cabal-3.10.1.0 init -m -n -d base,cipher-aes128
[Log] Using cabal specification: 3.0
[Warning] unknown license type, you must put a copy in LICENSE yourself.
[Log] Creating fresh file CHANGELOG.md...
[Log] Creating fresh directory ./app...
[Log] Creating fresh file app/Main.hs...
[Log] Creating fresh file cabal-issue9294.cabal...
[Warning] No synopsis given. You should edit the .cabal file and add one.
[Info] You may want to edit the .cabal file and add a Description field.

$ cabal-3.10.1.0 build
Resolving dependencies...
Error: cabal-3.10.1.0: Could not resolve dependencies:
....

Unfortunately relaxing the bound in cipher-aes128's custom-setup does not help:

❯ cabal-3.10.1.0 build --allow-newer=Cabal
Build profile: -w ghc-9.4.7 -O1
In order, the following will be built (use -v for more details):
 - cipher-aes128-0.7.0.6 (lib:cipher-aes128) (requires build)
 - cabal-issue9294-0.1.0.0 (exe:cabal-issue9294) (first run)
Starting     cipher-aes128-0.7.0.6 (all, legacy fallback)
Error: cabal-3.10.1.0: Failed to build cipher-aes128-0.7.0.6 (which is
required by exe:cabal-issue9294 from cabal-issue9294-0.1.0.0). The failure
occurred during the configure step. The exception was:
/home/andrea/.cabal/logs/ghc-9.4.7/cipher-aes128-0.7.0.6-ce595940690a94de95adb303a0f49bfb2e3cc3234d70cfc0d2542c368d373cb0.log:
withFile: user error (Error: cabal-3.10.1.0: '/home/andrea/.ghcup/bin/ghc'
exited with an error:

/home/andrea/Scratchpad/cabal-issue-9294/dist-newstyle/tmp/src-19690/cipher-aes128-0.7.0.6/dist/setup/setup.hs:36:66:
error:
Empty 'do' block
Suggested fix: Perhaps you intended to use NondecreasingIndentation
|
36 | withTempDirectory normal "" "testIntrinsic" $ \tmpDir -> do
| ^^
)

but this error has nothing to do with Cabal's API. It is a breaking change in GHC-9.2:

The default mode of GHC until 9.0 included NondecreasingIndentation, but GHC2021 does not. This may break code implicitly using this extension.

(taken from https://downloads.haskell.org/ghc/9.2.8/docs/html/users_guide/9.2.1-notes.html?highlight=nondecreasingindentation)

Indeed cabal-3.10.1.0 build -w ghc-9.0 works fine.

But this side-steps the upper bound on Cabal because ghc-9.0 comes with Cabal-3.4.1.0! I hear you saying. Well no, you can build Cabal-3.10.1.0 on ghc-9.0 and everything would work:

❯ cabal-3.10.1.0 build -w ghc-9.0 --constraint=cipher-aes128:setup.Cabal==3.10.1.0 --allow-newer=cipher-aes128:Cabal
Resolving dependencies...
Build profile: -w ghc-9.0.2 -O1
In order, the following will be built (use -v for more details):
 - Cabal-syntax-3.10.1.0 (lib) (requires build)
 - Cabal-3.10.1.0 (lib) (requires build)
 - cipher-aes128-0.7.0.6 (lib:cipher-aes128) (requires build)
 - cabal-issue9294-0.1.0.0 (exe:cabal-issue9294) (configuration changed)
Starting     Cabal-syntax-3.10.1.0 (lib)
Building     Cabal-syntax-3.10.1.0 (lib)
Installing   Cabal-syntax-3.10.1.0 (lib)
Completed    Cabal-syntax-3.10.1.0 (lib)
Starting     Cabal-3.10.1.0 (lib)
Building     Cabal-3.10.1.0 (lib)
Installing   Cabal-3.10.1.0 (lib)
Completed    Cabal-3.10.1.0 (lib)
Starting     cipher-aes128-0.7.0.6 (all, legacy fallback)
Building     cipher-aes128-0.7.0.6 (all, legacy fallback)
Installing   cipher-aes128-0.7.0.6 (all, legacy fallback)
Completed    cipher-aes128-0.7.0.6 (all, legacy fallback)
Configuring executable 'cabal-issue9294' for cabal-issue9294-0.1.0.0..
Preprocessing executable 'cabal-issue9294' for cabal-issue9294-0.1.0.0..
Building executable 'cabal-issue9294' for cabal-issue9294-0.1.0.0..
Linking /home/andrea/Scratchpad/cabal-issue-9294/dist-newstyle/build/x86_64-linux/ghc-9.0.2/cabal-issue9294-0.1.0.0/x/cabal-issue9294/build/cabal-issue9294/cabal-issue9294 ...

[andreabedini]

Is there a bug here? This issue can be turned into a UX issue if anyone is keen.

[andreabedini]

I am going to close this as I don't think there is a bug anywhere. Feel free to reopen in case I am mistaken.