Ensure js-sources are used only with JavaScript arch (backport #8748)

Cabal/src/Distribution/Simple/GHC.hs

@@ -523,7 +523,8 @@ buildOrReplLib mReplFlags verbosity numJobs pkg_descr lbi lib clbi = do
       comp = compiler lbi
       ghcVersion = compilerVersion comp
       implInfo  = getImplInfo comp
-      platform@(Platform _hostArch hostOS) = hostPlatform lbi
+      platform@(Platform hostArch hostOS) = hostPlatform lbi
+      hasJsSupport = hostArch == JavaScript
       has_code = not (componentIsIndefinite clbi)
 
   relLibTargetDir <- makeRelativeToCurrentDirectory libTargetDir
@@ -567,11 +568,13 @@ buildOrReplLib mReplFlags verbosity numJobs pkg_descr lbi lib clbi = do
                       , toNubListR (cxxSources libBi)
                       , toNubListR (cmmSources libBi)
                       , toNubListR (asmSources libBi)
-                      , toNubListR (jsSources  libBi)
+                      , if hasJsSupport
                         -- JS files are C-like with GHC's JS backend: they are
                         -- "compiled" into `.o` files (renamed with a header).
                         -- This is a difference from GHCJS, for which we only
                         -- pass the JS files at link time.
+                        then toNubListR (jsSources  libBi)
+                        else mempty
                       ]
       cLikeObjs   = map (`replaceExtension` objExtension) cLikeSources
       baseOpts    = componentGhcOptions verbosity lbi libBi clbi libTargetDir
@@ -730,7 +733,7 @@ buildOrReplLib mReplFlags verbosity numJobs pkg_descr lbi lib clbi = do
       | filename <- cSources libBi]
 
   -- build any JS sources
-  unless (not has_code || null (jsSources libBi)) $ do
+  unless (not has_code || not hasJsSupport || null (jsSources libBi)) $ do
     info verbosity "Building JS Sources..."
     sequence_
       [ do let vanillaJsOpts = Internal.componentJsGhcOptions verbosity implInfo
@@ -2087,7 +2090,10 @@ installLib verbosity lbi targetDir dynlibTargetDir _builtDir pkg lib clbi = do
                    && null (cxxSources (libBuildInfo lib))
                    && null (cmmSources (libBuildInfo lib))
                    && null (asmSources (libBuildInfo lib))
-                   && null (jsSources (libBuildInfo lib))
+                   && (null (jsSources (libBuildInfo lib)) || not hasJsSupport)
+    hasJsSupport = case hostPlatform lbi of
+      Platform JavaScript _ -> True
+      _                     -> False
     has_code = not (componentIsIndefinite clbi)
     whenHasCode = when has_code
     whenVanilla = when (hasLib && withVanillaLib lbi)

Cabal/src/Distribution/Simple/Register.hs

@@ -466,8 +466,11 @@ generalInstalledPackageInfo adjustRelIncDirs pkg abi_hash lib lbi clbi installDi
                              || not (null (asmSources bi))
                              || not (null (cmmSources bi))
                              || not (null (cxxSources bi))
-                             || not (null (jsSources bi)))
+                             || (not (null (jsSources bi)) && hasJsSupport))
                && not (componentIsIndefinite clbi)
+    hasJsSupport = case hostPlatform lbi of
+      Platform JavaScript _ -> True
+      _                     -> False
     libdirsStatic
       | hasLibrary = libdir installDirs : extraLibDirsStaticOrFallback
       | otherwise  =                      extraLibDirsStaticOrFallback

cabal-testsuite/PackageTests/JS/JsSources/jssources.cabal

@@ -6,7 +6,10 @@ build-type: Simple
 library
   default-language: Haskell2010
   js-sources: jsbits/lib.js
-  hs-source-dirs: src
+  if arch(JavaScript)
+    hs-source-dirs: srcJS
+  else
+    hs-source-dirs: src
   exposed-modules: Lib
   build-depends: base
 

cabal-testsuite/PackageTests/JS/JsSources/other-arch.out

@@ -0,0 +1,12 @@
+# cabal v2-run
+Resolving dependencies...
+Build profile: -w ghc-<GHCVER> -O1
+In order, the following will be built:
+ - jssources-0 (lib) (first run)
+ - jssources-0 (exe:demo) (first run)
+Configuring library for jssources-0..
+Preprocessing library for jssources-0..
+Building library for jssources-0..
+Configuring executable 'demo' for jssources-0..
+Preprocessing executable 'demo' for jssources-0..
+Building executable 'demo' for jssources-0..

cabal-testsuite/PackageTests/JS/JsSources/other-arch.test.hs

@@ -0,0 +1,7 @@
+import Test.Cabal.Prelude
+
+main = cabalTest $ do
+    skipIfJavaScript
+    -- Ensure the field `js-sources` does not raise issues
+    res <- cabal' "v2-run" ["demo"]
+    assertOutputContains "Hello Not JS!" res

cabal-testsuite/PackageTests/JS/JsSources/src/Lib.hs

@@ -1,3 +1,4 @@
 module Lib where
 
-foreign import javascript foo :: IO ()
+foo :: IO ()
+foo = putStrLn "Hello Not JS!"

cabal-testsuite/PackageTests/JS/JsSources/srcJS/Lib.hs

@@ -0,0 +1,3 @@
+module Lib where
+
+foreign import javascript foo :: IO ()