Fix default Nix configuration option in generated ~/.cabal/config file (#8878)

* default to commented line for nix config

* Fix whitespace

* Remove vscode folder

* Remove default config file for test

* Remove test generated file

* Add changelog

* Add test for default config values

* Remove config file

* Remove parsing file

* Add config file back for tests

* Remove reference to default config to try to get the new test to pass

* Rewrite test to be more verbose WIP

* Stop testing for values and only test for whether it is commented or not

* Fill out rest of tests WIP

* Clean up

---------

Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

Author: erinclemmer

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

@@ -915,7 +915,8 @@ commentSavedConfig = do
   globalInstallDirs <- defaultInstallDirs defaultCompiler False True
   let conf0 = mempty {
         savedGlobalFlags       = defaultGlobalFlags {
-            globalRemoteRepos = toNubList [defaultRemoteRepo]
+            globalRemoteRepos = toNubList [defaultRemoteRepo],
+            globalNix         = mempty
             },
         savedInitFlags       = mempty {
             IT.interactive     = toFlag False,

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

@@ -369,7 +369,7 @@ globalCommand commands = CommandUI {
           optArg' "(True or False)" (maybeToFlag . (readMaybe =<<)) (\case
             Flag True -> [Just "enable"]
             Flag False -> [Just "disable"]
-            NoFlag -> [Just "disable"]) "" ["nix"]
+            NoFlag -> []) "" ["nix"] -- Must be empty because we need to return PP.empty from viewAsFieldDescr
             "Nix integration: run commands through nix-shell if a 'shell.nix' file exists (default is False)",
           noArg (Flag True) [] ["enable-nix"]
           "Enable Nix integration: run commands through nix-shell if a 'shell.nix' file exists",

cabal-install/tests/IntegrationTests2.hs

@@ -9,8 +9,8 @@
 --
 -- This config file was generated using the following versions
 -- of Cabal and cabal-install:
--- Cabal library version: 3.6.2.0
--- cabal-install version: 3.6.2.0
+-- Cabal library version: 3.11.0.0
+-- cabal-install version: 3.11
 
 
 repository hackage.haskell.org
@@ -19,15 +19,15 @@ repository hackage.haskell.org
   -- root-keys:
   -- key-threshold: 3
 
--- default-user-config:
 -- ignore-expiry: False
 -- http-transport:
--- nix: False
--- local-no-index-repo:
-
---debug-info: 1
+-- nix:
 -- store-dir:
 -- active-repositories:
+-- local-no-index-repo:
+remote-repo-cache: /home/colton/.cabal/packages
+-- logs-dir: /home/colton/.cabal/logs
+-- default-user-config:
 -- verbose: 1
 -- compiler: ghc
 -- cabal-file:
@@ -47,6 +47,7 @@ repository hackage.haskell.org
 -- library-profiling-detail:
 -- optimization: True
 -- debug-info: False
+-- build-info:
 -- library-for-ghci:
 -- split-sections: False
 -- split-objs: False
@@ -60,7 +61,9 @@ repository hackage.haskell.org
 -- deterministic:
 -- cid:
 -- extra-lib-dirs:
+-- extra-lib-dirs-static:
 -- extra-framework-dirs:
+extra-prog-path: /home/colton/.cabal/bin
 -- instantiate-with:
 -- tests: False
 -- coverage: False
@@ -71,6 +74,8 @@ repository hackage.haskell.org
 -- response-files:
 -- allow-depending-on-private-libs:
 -- cabal-lib-version:
+-- append:
+-- backup:
 -- constraint:
 -- preference:
 -- solver: modular
@@ -87,6 +92,7 @@ repository hackage.haskell.org
 -- fine-grained-conflicts: True
 -- minimize-conflict-set: False
 -- independent-goals: False
+-- prefer-oldest: False
 -- shadow-installed-packages: False
 -- strong-flags: False
 -- allow-boot-library-installs: False
@@ -98,11 +104,11 @@ repository hackage.haskell.org
 -- index-state:
 -- root-cmd:
 -- symlink-bindir:
+build-summary: /home/colton/.cabal/logs/build.log
 -- build-log:
 remote-build-reporting: none
 -- report-planning-failure: False
 -- per-component: True
--- one-shot: False
 -- run-tests:
 jobs: $ncpus
 -- keep-going: False
@@ -111,6 +117,7 @@ jobs: $ncpus
 -- package-env:
 -- overwrite-policy:
 -- install-method:
+installdir: /home/colton/.cabal/bin
 -- username:
 -- password:
 -- password-command:
@@ -132,18 +139,28 @@ haddock
   -- quickjump: False
   -- hscolour-css:
   -- contents-location:
+  -- index-location:
+  -- base-url:
+  -- lib:
+  -- output-dir:
 
 init
   -- interactive: False
-  -- cabal-version: 2.4
+  -- quiet: False
+  -- no-comments: False
+  -- minimal: False
+  -- cabal-version: 3.0
   -- license:
+  -- extra-doc-file:
   -- tests:
   -- test-dir:
+  -- simple: False
   -- language: Haskell2010
   -- application-dir: app
   -- source-dir: src
 
 install-dirs user
+  -- prefix: /home/colton/.cabal
   -- bindir: $prefix/bin
   -- libdir: $prefix/lib
   -- libsubdir: $abi/$libname
@@ -226,4 +243,4 @@ program-default-options
   -- runghc-options:
   -- strip-options:
   -- tar-options:
-  -- uhc-options:
+  -- uhc-options:

cabal-install/tests/IntegrationTests2/nix-config/default-config renamed to cabal-install/tests/IntegrationTests2/config/default-config

@@ -0,0 +1,9 @@
+synopsis: Fix default Nix configuration option in generated ~/.cabal/config file
+packages: cabal-install
+prs: #8878
+
+description: {
+
+Fixes the default for ~/.cabal/config file. The nix option should now be commented out by default.
+
+}