Re #6542 Step 1 - Stack acknowledges that build type Hooks unsupported

ChangeLog.md

@@ -10,6 +10,8 @@ Major changes:
 
 Behavior changes:
 
+* When applicable, Stack reports that build type `Hooks` is unsupported.
+
 Other enhancements:
 
 * Consider Cabal 3.18 to be a tested library and remove warnings.

doc/commands/build_command.md

@@ -241,6 +241,11 @@ custom setup. That should list the dependencies needed to compile `Setup.hs`.
 Stack further customises the setup, using the `Cabal` package. If that package
 is not listed, Stack will warn and add the GHC boot package as a dependency.
 
+!!! note
+
+    Version 3.14 of the Cabal package description format specification
+    introduced the `Hooks` build type. Stack does not support the build type.
+
 In addition to specifying targets, you can also control what gets built, or
 retained, with the flags and options listed below. You can also affect what gets
 built by specifying Cabal (the library) options for the configure step

doc/maintainers/stack_errors.md

@@ -5,7 +5,7 @@
 In connection with considering Stack's support of the
 [Haskell Error Index](https://errors.haskell.org/) initiative, this page seeks
 to take stock of the errors that Stack itself can raise, by reference to the
-`master` branch of the Stack repository. Last updated: 2026-07-07.
+`master` branch of the Stack repository. Last updated: 2026-10-20.
 
 *   `Stack.main`: catches exceptions from action `commandLineHandler`.
 
@@ -228,6 +228,12 @@ to take stock of the errors that Stack itself can raise, by reference to the
         [S-2016] | Couldn'tParseField Text [Line]
         ~~~
 
+    -   `Stack.PackageFile.PackageFilePrettyException`
+
+        ~~~haskell
+        [S-2211] = HooksBuildTypeUnsupported PackageName
+        ~~~
+
     -   `Stack.Query.QueryException`
 
         ~~~haskell

src/Stack/PackageFile.hs

@@ -46,6 +46,26 @@ import           Stack.Types.PackageFile
 import qualified System.FilePath as FilePath
 import           System.IO.Error ( isUserError )
 
+-- | Type representing \'pretty\' exceptions thrown by functions exported by the
+-- "Stack.PackageFile" module.
+newtype PackageFilePrettyException
+  = HooksBuildTypeUnsupported PackageName
+  deriving Show
+
+instance Pretty PackageFilePrettyException where
+  pretty (HooksBuildTypeUnsupported pkgName) =
+    "[S-2211]"
+    <> line
+    <> fillSep
+         [ flow "The package"
+         , style Error . fromPackageName $ pkgName
+         , flow "specifies build type"
+         , style Shell "Hooks"
+         , flow "but that build type is unsupported."
+         ]
+
+instance Exception PackageFilePrettyException
+
 -- | Resolve the file, if it can't be resolved, warn for the user
 -- (purely to be helpful).
 resolveFileOrWarn ::
@@ -156,20 +176,20 @@ getPackageFile pkg cabalFP =
       runRIO
         (GetPackageFileContext cabalFP distDir bc cabalVer)
         (packageDescModulesAndFiles pkg)
-    setupFiles <-
-      if pkg.buildType == Cabal.Custom
-        then do
-          let setupHsPath = pkgDir </> relFileSetupHs
-              setupLhsPath = pkgDir </> relFileSetupLhs
-          setupHsExists <- doesFileExist setupHsPath
-          if setupHsExists
-            then pure (S.singleton setupHsPath)
-            else do
-              setupLhsExists <- doesFileExist setupLhsPath
-              if setupLhsExists
-                then pure (S.singleton setupLhsPath)
-                else pure S.empty
-        else pure S.empty
+    setupFiles <- case pkg.buildType of
+      Cabal.Custom -> do
+        let setupHsPath = pkgDir </> relFileSetupHs
+            setupLhsPath = pkgDir </> relFileSetupLhs
+        setupHsExists <- doesFileExist setupHsPath
+        if setupHsExists
+          then pure (S.singleton setupHsPath)
+          else do
+            setupLhsExists <- doesFileExist setupLhsPath
+            if setupLhsExists
+              then pure (S.singleton setupLhsPath)
+              else pure S.empty
+      Cabal.Hooks -> prettyThrowM $ HooksBuildTypeUnsupported pkg.name
+      _ -> pure S.empty
     moreBuildFiles <- fmap (S.insert cabalFP . S.union setupFiles) $ do
       let hpackPath = pkgDir </> relFileHpackPackageConfig
       hpackExists <- doesFileExist hpackPath