hadrian: Pass haddock file arguments in a response filewip/t23273

In !10119 CI was failing on windows because the command line was too
long. We can mitigate this by passing the file arguments to haddock in a
response file.

We can't easily pass all the arguments in a response file because the
`+RTS` arguments can't be placed in the response file.

Fixes #23273

2 files changed, 13 insertions, 1 deletions

diff --git a/hadrian/src/Builder.hs b/hadrian/src/Builder.hs
index 77c0f514d6..39cc33ee3c 100644
--- a/hadrian/src/Builder.hs
+++ b/hadrian/src/Builder.hs
@@ -41,6 +41,7 @@ import Packages
 import GHC.IO.Encoding (getFileSystemEncoding)
 import qualified Data.ByteString as BS
 import qualified GHC.Foreign as GHC
+import GHC.ResponseFile
 
 -- | C compiler can be used in two different modes:
 -- * Compile or preprocess a source file.
@@ -353,6 +354,8 @@ instance H.Builder Builder where
                     Exit _ <- cmd' [path] (buildArgs ++ [input])
                     return ()
 
+                Haddock BuildPackage -> runHaddock path buildArgs buildInputs
+
                 HsCpp    -> captureStdout
 
                 Make dir -> cmd' path ["-C", dir] buildArgs
@@ -385,6 +388,16 @@ instance H.Builder Builder where
 
                 _  -> cmd' [path] buildArgs
 
+-- | Invoke @haddock@ given a path to it and a list of arguments. The arguments
+-- are passed in a response file.
+runHaddock :: FilePath    -- ^ path to @haddock@
+      -> [String]
+      -> [FilePath]  -- ^ input file paths
+      -> Action ()
+runHaddock haddockPath flagArgs fileInputs = withTempFile $ \tmp -> do
+    writeFile' tmp $ escapeArgs fileInputs
+    cmd [haddockPath] flagArgs ('@' : tmp)
+
 -- TODO: Some builders are required only on certain platforms. For example,
 -- 'Objdump' is only required on OpenBSD and AIX. Add support for platform
 -- specific optional builders as soon as we can reliably test this feature.
diff --git a/hadrian/src/Settings/Builders/Haddock.hs b/hadrian/src/Settings/Builders/Haddock.hs
index 9ecdabfec7..3d1fb28fc5 100644
--- a/hadrian/src/Settings/Builders/Haddock.hs
+++ b/hadrian/src/Settings/Builders/Haddock.hs
@@ -68,7 +68,6 @@ haddockBuilderArgs = mconcat
                      ++ "," ++ baseUrl p ++ "/src/%{MODULE}.html#%{NAME},"
                      ++ haddock | (p, haddock) <- haddocks_with_versions ]
             , pure [ "--optghc=" ++ opt | opt <- ghcOpts, not ("--package-db" `isInfixOf` opt) ]
-            , getInputs
             , arg "+RTS"
             , arg $ "-t" ++ (statsDir -/- pkgName pkg ++ ".t")
             , arg "--machine-readable"