Merge pull request #5825 from mpilgrem/uninstall

Make `stack uninstall` informative

Author: mpilgrem

ChangeLog.md

@@ -37,6 +37,7 @@ Other enhancements:
 * Add the possibility of a `sh` script to customise fully GHC installation. See
   [#5585](https://github.com/commercialhaskell/stack/pull/5585)
 * `tools` subcommand added to `stack ls`, to list stack's installed tools.
+* `stack uninstall` shows how to uninstall Stack.
 
 Bug fixes:
 

doc/GUIDE.md

@@ -1175,18 +1175,17 @@ On Windows (with PowerShell):
     -a---          25/02/2022 11:39 PM              9 msys2-20210604.installed
 
 While we're talking about paths, to wipe our Stack install completely, here's
-what needs to be removed:
-
-1. Delete the Stack root folder (see `stack path --stack-root`, before you
-   uninstall).
-2. On Windows, delete the folder containing Stack's tools (see
-   `stack path --programs`, before you uninstall), which is located outside of
-   the Stack root folder
-3. Delete the `stack` executable (see `which stack`, on Unix-like operating
+what typically needs to be removed:
+
+1. the Stack root folder (see `stack path --stack-root`, before you uninstall);
+2. on Windows, the folder containing Stack's tools (see `stack path --programs`,
+   before you uninstall), which is located outside of the Stack root folder; and
+3. the `stack` executable file (see `which stack`, on Unix-like operating
    systems, or `where.exe stack`, on Windows).
 
-You may also want to delete ``.stack-work`` folders in any Haskell projects that
-you have built using Stack.
+You may also want to delete `.stack-work` folders in any Haskell projects that
+you have built using Stack. The `stack uninstall` command provides information
+about how to uninstall Stack.
 
 ## The `stack exec` command
 

doc/README.md

@@ -231,15 +231,14 @@ found in the current directory.
 
 ## How to uninstall
 
-To uninstall Stack, it should be sufficient to:
-
-1. Delete the Stack root folder (see `stack path --stack-root`, before you
-   uninstall).
-2. On Windows, delete the folder containing Stack's tools (see
-   `stack path --programs`, before you uninstall), which is located outside of
-   the Stack root folder
-3. Delete the `stack` executable (see `which stack`, on Unix-like operating
+To uninstall Stack, it should be sufficient to delete:
+
+1. the Stack root folder (see `stack path --stack-root`, before you uninstall);
+2. on Windows, the folder containing Stack's tools (see `stack path --programs`,
+   before you uninstall), which is located outside of the Stack root folder; and
+3. the `stack` executable file (see `which stack`, on Unix-like operating
    systems, or `where.exe stack`, on Windows).
 
 You may also want to delete ``.stack-work`` folders in any Haskell projects that
-you have built using Stack.
+you have built using Stack. The `stack uninstall` command provides information
+about how to uninstall Stack.

src/main/Main.hs

@@ -197,9 +197,11 @@ commandLineHandler currentDir progName isInterpreter = complicatedOptions
                          buildCmd
                          (buildOptsParser Install)
         addCommand' "uninstall"
-                    "DEPRECATED: This command performs no actions, and is present for documentation only"
+         (unwords [ "Show how to uninstall Stack. This command does not"
+                  , "itself uninstall Stack."
+                  ] )
                     uninstallCmd
-                    (many $ strArgument $ metavar "IGNORED")
+                    (pure())
         addBuildCommand' "test"
                          "Shortcut for 'build --test'"
                          buildCmd
@@ -575,15 +577,33 @@ buildCmd opts = do
         Install -> set (globalOptsBuildOptsMonoidL.buildOptsMonoidInstallExesL) (Just True)
         Build -> id -- Default case is just Build
 
-uninstallCmd :: [String] -> RIO Runner ()
-uninstallCmd _ = do
-    prettyErrorL
-      [ flow "stack does not manage installations in global locations."
-      , flow "The only global mutation stack performs is executable copying."
-      , flow "For the default executable destination, please run"
-      , PP.style Shell "stack path --local-bin"
-      ]
-    liftIO exitFailure
+-- | Display help for the uninstall command.
+uninstallCmd :: () -> RIO Runner ()
+uninstallCmd () = withConfig NoReexec $ do
+  stackRoot <- view stackRootL
+  programsDir <- view $ configL.to configLocalProgramsBase
+  localBinDir <- view $ configL.to configLocalBin
+  let toStyleDoc = PP.style Dir . fromString . toFilePath
+      stackRoot' = toStyleDoc stackRoot
+      programsDir' = toStyleDoc programsDir
+      localBinDir' = toStyleDoc localBinDir
+  prettyInfo $ vsep
+    [ flow "To uninstall Stack, it should be sufficient to delete:"
+    , hang 4 $ fillSep [flow "(1) the directory containing Stack's tools",
+      "(" <> softbreak <> programsDir' <> softbreak <> ");"]
+    , hang 4 $ fillSep [flow "(2) the Stack root directory",
+      "(" <> softbreak <> stackRoot' <> softbreak <> ");", "and"]
+    , hang 4 $ fillSep [flow "(3) the 'stack' executable file (see the output",
+      flow "of command", howToFindStack <> ",", flow "if Stack is on the PATH;",
+      flow "Stack is often installed in", localBinDir' <> softbreak <> ")."]
+    , fillSep [flow "You may also want to delete", PP.style File ".stack-work",
+      flow "directories in any Haskell projects that you have built."]
+    ]
+ where
+  styleShell = PP.style Shell
+  howToFindStack
+    | osIsWindows = styleShell "where.exe stack"
+    | otherwise   = styleShell "which stack"
 
 -- | Unpack packages to the filesystem
 unpackCmd :: ([String], Maybe Text) -> RIO Runner ()