Merge pull request #5918 from commercialhaskell/re5911-configcmd

Re #5911 Tidy up exceptions in Stack.ConfigCmd
commercialhaskell · Oct 28, 2022 · 21ab7f5 · 21ab7f5
2 parents 909d5a7 + 445a56f
commit 21ab7f5
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Showing 2 changed files with 18 additions and 9 deletions.
diff --git a/doc/maintainers/stack_errors.md b/doc/maintainers/stack_errors.md
@@ -190,6 +190,12 @@ to take stock of the errors that Stack itself can raise, by reference to the
         = NixCannotUseShellFileAndPackagesException
         ~~~
 
+    -   `Stack.ConfigCmd.ConfigCmdException`
+
+        ~~~haskell
+        = NoProjectConfigAvailable
+        ~~~
+
     -   `Stack.Types.Build.StackBuildException`
 
         ~~~haskell
@@ -442,14 +448,6 @@ to take stock of the errors that Stack itself can raise, by reference to the
     <path>
     ~~~
 
-*   `Stack.ConfigCmd.cfgCmdSet`:
-
-    ~~~text
-    config command used when no project configuration available
-    ~~~
-
-    `throwString`
-
 *   `Stack.Config.Nix.nixCompiler`:
 
     ~~~text

diff --git a/src/Stack/ConfigCmd.hs b/src/Stack/ConfigCmd.hs
@@ -40,6 +40,16 @@ import           Stack.Types.Config
 import           Stack.Types.Resolver
 import           System.Environment (getEnvironment)
 
+data ConfigCmdException
+    = NoProjectConfigAvailable
+    deriving (Typeable)
+
+instance Show ConfigCmdException where
+    show NoProjectConfigAvailable =
+        "Error: config command used when no project configuration available"
+
+instance Exception ConfigCmdException
+
 data ConfigCmdSet
     = ConfigCmdSetResolver !(Unresolved AbstractResolver)
     | ConfigCmdSetSystemGhc !CommandScope !Bool
@@ -72,7 +82,8 @@ cfgCmdSet cmd = do
                      case mstackYaml of
                          PCProject stackYaml -> pure stackYaml
                          PCGlobalProject -> liftM (</> stackDotYaml) (getImplicitGlobalProjectDir conf)
-                         PCNoProject _extraDeps -> throwString "config command used when no project configuration available" -- maybe modify the ~/.stack/config.yaml file instead?
+                         PCNoProject _extraDeps -> throwIO NoProjectConfigAvailable
+                         -- maybe modify the ~/.stack/config.yaml file instead?
                  CommandScopeGlobal -> pure (configUserConfigPath conf)
     rawConfig <- liftIO (readFileUtf8 (toFilePath configFilePath))
     config <- either throwM pure (Yaml.decodeEither' $ encodeUtf8 rawConfig)