[Git][ghc/ghc][wip/davide/hadrian_avoid_response_files] Hadrian: disable response files for GHC/Haddock builders on non-Windows

30 May 2026

David Eichmann pushed to branch wip/davide/hadrian_avoid_response_files at Glasgow Haskell Compiler / GHC


Commits:
52935fea by David Eichmann at 2026-05-29T17:19:55+01:00
Hadrian: disable response files for GHC/Haddock builders on non-Windows

This makes debugging build errors easier on non-windows hosts.
See issue #27230

- - - - -


2 changed files:

- hadrian/src/Builder.hs
- hadrian/src/Hadrian/Utilities.hs


Changes:

=====================================
hadrian/src/Builder.hs
=====================================
@@ -346,7 +346,16 @@ instance H.Builder Builder where
 
                 Haddock BuildPackage -> runHaddock path buildArgs buildInputs
 
-                Ghc _ _ -> runGhcWithResponse path buildArgs buildInputs buildOptions
+                Ghc _ _ ->
+                  -- Use a response file for ghc invocations to avoid issues with command line
+                  -- size limit on Windows (#26637).
+                  -- Note we can't put the buildArgs in a response file, because some flags require
+                  -- empty arguments (such as the -dep-suffix flag), but that isn't supported
+                  -- yet due to #26560.
+                  withResponseFileOnWindows
+                    buildInputs
+                    (escapeArgs buildInputs)
+                    (\buildInputs' -> cmd [path] buildArgs buildInputs' buildOptions)
 
                 HsCpp    -> captureStdout
 
@@ -386,23 +395,10 @@ runHaddock :: FilePath    -- ^ path to @haddock@
       -> [String]
       -> [FilePath]  -- ^ input file paths
       -> Action ()
-runHaddock haddockPath flagArgs fileInputs = withResponseFile $ \tmp -> do
-    writeFile' tmp $ escapeArgs fileInputs
-    cmd [haddockPath] flagArgs ('@' : tmp)
-

--- | Use a response file for ghc invocations to avoid issues with command line
--- size limit on Windows (#26637).
-runGhcWithResponse :: FilePath -- ^ Path to ghc
-  -> [String] -- ^ Arguments passed on the command line
-  -> [FilePath] -- ^ Input file paths (passed via response file)
-  -> [CmdOption]
-  -> Action ()
-runGhcWithResponse ghcPath buildArgs buildInputs buildOptions = withResponseFile $ \tmp -> do
-  -- We can't put the buildArgs in a response file, because some flags require
-  -- empty arguments (such as the -dep-suffix flag), but that isn't supported
-  -- yet due to #26560.
-  writeFile' tmp (escapeArgs buildInputs)
-  cmd [ghcPath] buildArgs ('@' : tmp) buildOptions
+runHaddock haddockPath flagArgs fileInputs = withResponseFileOnWindows
+  fileInputs
+  (escapeArgs fileInputs)
+  (\fileInputs' -> cmd [haddockPath] flagArgs fileInputs')
 
 -- TODO: Some builders are required only on certain platforms. For example,
 -- 'Objdump' is only required on OpenBSD and AIX. Add support for platform


=====================================
hadrian/src/Hadrian/Utilities.hs
=====================================
@@ -14,7 +14,7 @@ module Hadrian.Utilities (
 
     -- * Paths
     BuildRoot (..), buildRoot, buildRootRules, isGeneratedSource,
-    KeepResponseFiles (..), keepResponseFiles, withResponseFile,
+    KeepResponseFiles (..), keepResponseFiles, withResponseFile, withResponseFileOnWindows,
 
     -- * File system operations
     copyFile, copyFileUntracked, createFileLink, fixFile,
@@ -49,7 +49,9 @@ import Development.Shake hiding (Normal)
 import Development.Shake.Classes
 import Development.Shake.FilePath
 import System.Environment (lookupEnv)
+import System.Info.Extra (isWindows)
 import System.IO (hClose, openTempFile)
+import System.IO.Error (isPermissionError)
 
 import qualified Data.ByteString        as BS
 import qualified Control.Exception.Base as IO
@@ -57,8 +59,7 @@ import qualified Data.HashMap.Strict    as Map
 import qualified System.Directory.Extra as IO
 import qualified System.Info.Extra      as IO
 import qualified System.IO              as IO
-import System.IO.Error (isPermissionError)
-import qualified System.FilePath.Posix as Posix
+import qualified System.FilePath.Posix  as Posix
 
 -- | Extract a value from a singleton list, or terminate with an error message
 -- if the list does not contain exactly one value.
@@ -328,6 +329,23 @@ keepResponseFiles = do
     KeepResponseFiles keep <- userSetting (KeepResponseFiles False)
     return keep
 
+-- | Run an action either with command arguments direcly or by, on windows,
+-- placing those arguments into a response file (initialized to some string).
+--
+-- With @--keep-response-files@, the file is left on disk (if used)
+withResponseFileOnWindows ::
+    [String]                      -- ^ Command arguments
+    -> String                     -- ^ Response file content (the command arguments converted to the response file format).
+    -> ([String] -> Action a)     -- ^ Perform an action with the given command arguments or, on windows, the with the
+                                  --   response file initialized and the passed argument is in the form ["@reponseFilePath"]
+    -> Action a
+withResponseFileOnWindows commandArgs responseFileContent action = do
+    if isWindows
+        then withResponseFile $ \tmp -> do
+                writeFile' tmp responseFileContent
+                action ['@' : tmp]
+        else action commandArgs
+
 -- | Run an action with a response file path.
 --
 -- With @--keep-response-files@, the file is left on disk.



View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/52935feab3cdf20cc7c98f6214c38b4e...

-- 
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/52935feab3cdf20cc7c98f6214c38b4e...
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David Eichmann (＠DavidEichmann)

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