Warnings are dumped with color output (fixes #2997)

ChangeLog.md

@@ -202,6 +202,8 @@ Bug fixes:
   [#4598](https://github.com/commercialhaskell/stack/issues/4598)
 * Hackage credentials are not world-readable. See
   [#2159](https://github.com/commercialhaskell/stack/issues/2159).
+* Warnings are dumped from logs even when color is enabled. See
+  [#2997](https://github.com/commercialhaskell/stack/issues/2997)
 
 ## v1.9.3
 

src/Stack/Build/Execute.hs

@@ -420,6 +420,7 @@ withExecuteEnv bopts boptsCli baseConfigOpts locals globalPackages snapshotPacka
     isWarning :: Text -> Bool
     isWarning t = ": Warning:" `T.isSuffixOf` t -- prior to GHC 8
                || ": warning:" `T.isInfixOf` t -- GHC 8 is slightly different
+               || "mwarning:" `T.isInfixOf` t -- colorized output
 
     dumpLog :: String -> (Path Abs Dir, Path Abs File) -> RIO env ()
     dumpLog msgSuffix (pkgDir, filepath) = do

test/integration/tests/2997-ensure-warnings-output/Main.hs

@@ -0,0 +1,10 @@
+import StackTest
+import Data.List (isInfixOf)
+
+main :: IO ()
+main = do
+  stack ["clean", "--full"]
+  stackCheckStderr ["build", "--terminal", "--color=always"] $ \str ->
+    if "no type signature" `isInfixOf` str
+      then pure ()
+      else error "Warnings are not being shown"

test/integration/tests/2997-ensure-warnings-output/files/.gitignore

@@ -0,0 +1 @@
+*.cabal

test/integration/tests/2997-ensure-warnings-output/files/bar/package.yaml

@@ -0,0 +1,9 @@
+name: bar
+version: 0
+
+dependencies:
+- base
+
+library:
+  source-dirs: src
+  ghc-options: -Wall

test/integration/tests/2997-ensure-warnings-output/files/bar/src/Bar.hs

@@ -0,0 +1,3 @@
+module Bar where
+
+bar = ()

test/integration/tests/2997-ensure-warnings-output/files/foo/package.yaml

@@ -0,0 +1,9 @@
+name: foo
+version: 0
+
+dependencies:
+- base
+
+library:
+  source-dirs: src
+  ghc-options: -Wall

test/integration/tests/2997-ensure-warnings-output/files/foo/src/Foo.hs

@@ -0,0 +1,3 @@
+module Foo where
+
+foo = ()

test/integration/tests/2997-ensure-warnings-output/files/stack.yaml

@@ -0,0 +1,5 @@
+resolver: ghc-8.2.2
+packages:
+- foo
+- bar
+dump-logs: warning