Hadrian: run the testsuite in Windows CI job

Since MR !1025 fixed the Windows build, allowing us to build a binary
distribution, we can now run the testsuite in that CI job.

This required fixing 'createFileLink': it should not try to create
symlinks on Windows (that requires admin priviledges, which Hadrian can't
assume). We now instead fall back to copying.

This patch also removes some duplicated logic for iserv in the test rules,
where we handle our dependency on the iserv binaries in a special way.

.gitlab-ci.yml

@@ -710,14 +710,19 @@ validate-x86_64-linux-fedora27:
       bash -c './configure --enable-tarballs-autodownload GHC=`pwd`/toolchain/bin/ghc HAPPY=`pwd`/toolchain/bin/happy ALEX=`pwd`/toolchain/bin/alex'
     - bash -c "PATH=`pwd`/toolchain/bin:$PATH hadrian/build.cabal.sh -j`mk/detect-cpu-count.sh` --flavour=Quick --docs=no-sphinx binary-dist"
     - mv _build/bindist/ghc*.tar.xz ghc.tar.xz
-    # FIXME: Testsuite disabled due to #16156.
-    # - bash -c 'make V=0 test THREADS=`mk/detect-cpu-count.sh` JUNIT_FILE=../../junit.xml'
+    - bash -c "PATH=`pwd`/toolchain/bin:$PATH hadrian/build.cabal.sh -j`mk/detect-cpu-count.sh` --flavour=quick test --summary-junit=./junit.xml --skip-perf"
+    # skipping perf tests for now since we build a quick-flavoured GHC,
+    # which might result in some broken perf tests?
   tags:
     - x86_64-windows
   artifacts:
+    reports:
+      junit: junit.xml
+    expire_in: 2 week
     when: always
     paths:
       - ghc.tar.xz
+      - junit.xml
 
 validate-x86_64-windows-hadrian:
   extends: .build-windows-hadrian

hadrian/src/Hadrian/Utilities.hs

@@ -304,22 +304,25 @@ isGeneratedSource file = buildRoot <&> (`isPrefixOf` file)
 -- | Link a file tracking the link target. Create the target directory if
 -- missing.
 createFileLink :: FilePath -> FilePath -> Action ()
-createFileLink linkTarget link = do
+createFileLink linkTarget link
+  | windowsHost = copyFile' source link
+  | otherwise   = do
     -- TODO `disableHistory` is a temporary fix (see issue #16866). Remove
     -- `disableHistory` when shake issue is fixed: https://github.com/ndmitchell/shake/issues/683.
     historyDisable
 
-    let source = if isAbsolute linkTarget
-                    then linkTarget
-                    else takeDirectory link -/- linkTarget
     need [source]
-    let dir = takeDirectory link
+
     liftIO $ IO.createDirectoryIfMissing True dir
     putProgressInfo =<< renderCreateFileLink linkTarget link
     quietly . liftIO $ do
         IO.removeFile link <|> return ()
         IO.createFileLink linkTarget link
 
+  where dir = takeDirectory link
+        source | isAbsolute linkTarget = linkTarget
+               | otherwise             = takeDirectory link -/- linkTarget
+
 -- | Copy a file tracking the source. Create the target directory if missing.
 copyFile :: FilePath -> FilePath -> Action ()
 copyFile source target = do

hadrian/src/Rules/Test.hs

@@ -162,9 +162,10 @@ needTestsuitePackages = do
         allpkgs   <- packages <$> flavour
         stgpkgs   <- allpkgs (succ stg)
         testpkgs  <- testsuitePackages
-        targets <- mapM (needFile stg) (stgpkgs ++ testpkgs)
+        let pkgs = filter (\p -> not $ "iserv" `isInfixOf` pkgName p)
+                          (stgpkgs ++ testpkgs)
+        need =<< mapM (pkgFile stg) pkgs
         needIservBins
-        need targets
 
 -- stage 1 ghc lives under stage0/bin,
 -- stage 2 ghc lives under stage1/bin, etc
@@ -187,7 +188,7 @@ needIservBins = do
             , w `elem` rtsways
             ]
 
-needFile :: Stage -> Package -> Action FilePath
-needFile stage pkg
+pkgFile :: Stage -> Package -> Action FilePath
+pkgFile stage pkg
     | isLibrary pkg = pkgConfFile (Context stage pkg profilingDynamic)
     | otherwise     = programPath =<< programContext stage pkg