Print install command to fix missing transitive dependencies (#770)

Author: milesfrain

CHANGELOG.md

@@ -14,6 +14,7 @@ Other improvements:
 - Color output is now automatically disabled when output is redirected to a file.
   Also respects a [`NO_COLOR`](https://no-color.org/) environment variable (#768)
 - Fixes tests failing if the test platform has psa installed (#772)
+- Print `spago install` command to fix missing transitive dependencies (#770)
 
 ## [0.20.0] - 2021-04-07
 

src/Spago/Messages.hs

@@ -242,3 +242,5 @@ sourceImportsTransitiveDependency transitive = makeMessage $
   [ "Some of your project files import modules from packages that are not in the direct dependencies of your project."
   , "To fix this error add the following packages to the list of dependencies in your config:"
   ] <> map (\package -> "- " <> package) transitive
+  <> [ "You may add these dependencies by running the following command:"
+  , "spago install " <> Text.intercalate " " transitive ]

test/SpagoSpec.hs

@@ -425,9 +425,9 @@ spec = around_ setup $ do
       it "Spago should fail on direct project imports from transitive dependencies" $ do
         spago ["init"] >>= shouldBeSuccess
         rm "spago.dhall"
-        writeTextFile "spago.dhall" $ "{ name = \"check-imports\", dependencies = [\"effect\"], packages = ./packages.dhall }"
+        writeTextFile "spago.dhall" $ "{ name = \"check-imports\", dependencies = [\"effect\", \"lists\"], packages = ./packages.dhall }"
         rm "src/Main.purs"
-        writeTextFile "src/Main.purs" "module Main where\nimport Prelude\nmain = unit"
+        writeTextFile "src/Main.purs" "module Main where\nimport Prelude\nimport Data.Maybe\nimport Data.List\nmain = unit"
         rm "test/Main.purs"
         spago ["build"]
         spago ["--no-psa", "build"] >>= shouldBeFailureStderr "check-direct-import-transitive-dependency.txt"

test/fixtures/check-direct-import-transitive-dependency.txt

@@ -5,4 +5,7 @@ These dependencies are unused. To fix this warning, remove the following package
 - effect
 [error] Some of your project files import modules from packages that are not in the direct dependencies of your project.
 To fix this error add the following packages to the list of dependencies in your config:
+- maybe
 - prelude
+You may add these dependencies by running the following command:
+spago install maybe prelude