Show resolver being used when stack ghci is invoked outside of a project directory

ChangeLog.md

@@ -96,6 +96,8 @@ Other enhancements:
 * `get-stack` script now works on Windows CI machines of Appveyor,
   Travis and Azure Pipelines. See
   [#4535](https://github.com/commercialhaskell/stack/issues/4535)/
+* Show snapshot being used when `stack ghci` is invoked outside of a project directory. See
+  [#3651](https://github.com/commercialhaskell/stack/issues/3651)
 
 Bug fixes:
 

src/Stack/Config.hs

@@ -645,6 +645,7 @@ loadBuildConfig mproject maresolver mcompiler = do
           { smwCompiler = fromMaybe (snapshotCompiler snapshot)  mcompiler
           , smwProject = packages
           , smwDeps = deps
+          , smwSnapshotName = snapshotName snapshot
           }
 
     return BuildConfig

src/Stack/Ghci.hs

@@ -185,9 +185,8 @@ ghci opts@GhciOpts{..} = do
               pkgs0 <- getGhciPkgInfos installMap addPkgs (fmap fst mfileTargets) pkgDescs
               figureOutMainFile bopts mainIsTargets localTargets pkgs0
     -- Build required dependencies and setup local packages.
-    stackYaml <- view stackYamlL
     buildDepsAndInitialSteps opts (map (T.pack . packageNameString . fst) localTargets)
-    targetWarnings stackYaml localTargets nonLocalTargets mfileTargets
+    targetWarnings localTargets nonLocalTargets mfileTargets
     -- Load the list of modules _after_ building, to catch changes in
     -- unlisted dependencies (#1180)
     pkgs <- getGhciPkgInfos installMap addPkgs (fmap fst mfileTargets) pkgDescs
@@ -836,13 +835,12 @@ checkForDuplicateModules pkgs = do
       pretty fp <+> parens (fillSep (punctuate "," (map displayPkgComponent (S.toList comps))))
 
 targetWarnings
-  :: HasTerm env
-  => Path Abs File
-  -> [(PackageName, (Path Abs File, Target))]
+  :: HasBuildConfig env
+  => [(PackageName, (Path Abs File, Target))]
   -> [PackageName]
   -> Maybe (Map PackageName [Path Abs File], [Path Abs File])
   -> RIO env ()
-targetWarnings stackYaml localTargets nonLocalTargets mfileTargets = do
+targetWarnings localTargets nonLocalTargets mfileTargets = do
   unless (null nonLocalTargets) $
     prettyWarnL
       [ flow "Some targets"
@@ -853,10 +851,14 @@ targetWarnings stackYaml localTargets nonLocalTargets mfileTargets = do
       , "."
       , flow "It can still be useful to specify these, as they will be passed to ghci via -package flags."
       ]
-  when (null localTargets && isNothing mfileTargets) $
+  when (null localTargets && isNothing mfileTargets) $ do
+      smWanted <- view $ buildConfigL.to bcSMWanted
+      stackYaml <- view stackYamlL
       prettyNote $ vsep
           [ flow "No local targets specified, so a plain ghci will be started with no package hiding or package options."
           , ""
+          , flow $ "You are using snapshot: " ++ T.unpack (smwSnapshotName smWanted)
+          , ""
           , flow "If you want to use package hiding and options, then you can try one of the following:"
           , ""
           , bulletedList

src/Stack/Types/SourceMap.hs

@@ -87,6 +87,7 @@ data SMWanted = SMWanted
   { smwCompiler :: !WantedCompiler
   , smwProject :: !(Map PackageName ProjectPackage)
   , smwDeps :: !(Map PackageName DepPackage)
+  , smwSnapshotName :: !Text
   }
 
 -- | Adds in actual compiler information to 'SMWanted', in particular