From 24027915a25dac32544fd5a9761b7275fb5cebc8 Mon Sep 17 00:00:00 2001
From: Patrick Augusto <ptkato.irl@gmail.com>
Date: Wed, 30 Jun 2021 18:16:56 -0300
Subject: [PATCH] Suppress warnings for verbosity

---
 Cabal/src/Distribution/Simple/Utils.hs       |  2 +-
 Cabal/src/Distribution/Verbosity.hs          | 13 +++++++++++++
 Cabal/src/Distribution/Verbosity/Internal.hs |  1 +
 3 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/Cabal/src/Distribution/Simple/Utils.hs b/Cabal/src/Distribution/Simple/Utils.hs
index 26c727b4657..54c1b4c4408 100644
--- a/Cabal/src/Distribution/Simple/Utils.hs
+++ b/Cabal/src/Distribution/Simple/Utils.hs
@@ -442,7 +442,7 @@ verbosityHandle verbosity
 --
 warn :: Verbosity -> String -> IO ()
 warn verbosity msg = withFrozenCallStack $ do
-  when (verbosity >= normal) $ do
+  when ((verbosity >= normal) && not (isVerboseNoWarn verbosity)) $ do
     ts <- getPOSIXTime
     hFlush stdout
     hPutStr stderr . withMetadata ts NormalMark FlagTrace verbosity
diff --git a/Cabal/src/Distribution/Verbosity.hs b/Cabal/src/Distribution/Verbosity.hs
index 23ffaba1389..d73cbd8031d 100644
--- a/Cabal/src/Distribution/Verbosity.hs
+++ b/Cabal/src/Distribution/Verbosity.hs
@@ -52,6 +52,9 @@ module Distribution.Verbosity (
   -- * Stderr
   verboseStderr, isVerboseStderr,
   verboseNoStderr,
+
+  -- * No warnings
+  verboseNoWarn, isVerboseNoWarn
   ) where
 
 import Prelude ()
@@ -213,6 +216,7 @@ parsecVerbosity = parseIntVerbosity <|> parseStringVerbosity
             "timestamp"  -> return verboseTimestamp
             "stderr"     -> return verboseStderr
             "stdout"     -> return verboseNoStderr
+            "nowarn"     -> return verboseNoWarn
             _            -> P.unexpected $ "Bad verbosity flag: " ++ token
 
 flagToVerbosity :: ReadE Verbosity
@@ -239,6 +243,7 @@ showForCabal v
     showFlag VMarkOutput = ["+markoutput"]
     showFlag VTimestamp  = ["+timestamp"]
     showFlag VStderr     = ["+stderr"]
+    showFlag VNoWarn     = ["+nowarn"]
 
 showForGHC :: Verbosity -> String
 showForGHC   v = maybe (error "unknown verbosity") show $
@@ -290,6 +295,10 @@ verboseStderr = verboseFlag VStderr
 verboseNoStderr :: Verbosity -> Verbosity
 verboseNoStderr = verboseNoFlag VStderr
 
+-- | Turn off warnings for log messages
+verboseNoWarn :: Verbosity -> Verbosity
+verboseNoWarn = verboseFlag VNoWarn
+
 -- | Helper function for flag enabling functions
 verboseFlag :: VerbosityFlag -> (Verbosity -> Verbosity)
 verboseFlag flag v = v { vFlags = Set.insert flag (vFlags v) }
@@ -335,6 +344,10 @@ isVerboseTimestamp = isVerboseFlag VTimestamp
 isVerboseStderr :: Verbosity -> Bool
 isVerboseStderr = isVerboseFlag VStderr
 
+-- | Test if we should output warnings when we log.
+isVerboseNoWarn :: Verbosity -> Bool
+isVerboseNoWarn = isVerboseFlag VNoWarn
+
 -- | Helper function for flag testing functions.
 isVerboseFlag :: VerbosityFlag -> Verbosity -> Bool
 isVerboseFlag flag = (Set.member flag) . vFlags
diff --git a/Cabal/src/Distribution/Verbosity/Internal.hs b/Cabal/src/Distribution/Verbosity/Internal.hs
index ea436825dd4..21a4e6932c2 100644
--- a/Cabal/src/Distribution/Verbosity/Internal.hs
+++ b/Cabal/src/Distribution/Verbosity/Internal.hs
@@ -21,6 +21,7 @@ data VerbosityFlag
     | VMarkOutput
     | VTimestamp
     | VStderr -- ^ @since 3.4.0.0
+    | VNoWarn
     deriving (Generic, Show, Read, Eq, Ord, Enum, Bounded, Typeable)
 
 instance Binary VerbosityFlag