From 39f0eea533056c8a26da089a774a27b13097e489 Mon Sep 17 00:00:00 2001
From: Iustin Pop <iustin@google.com>
Date: Tue, 13 Nov 2012 11:46:04 +0100
Subject: [PATCH] Automatically enable version-dependent GHC flags
Some GHC flags are very useful, but only appear in more recent GHC
versions. To support the use of such flags while still supporting
older compilers, let's add conditional checks and enabling based on
the results.
Currently only `-fwarn-incomplete-uni-patterns` is enabled, which
detects refutable patterns in lambda expressions and pattern bindings
(e.g. "let (Just x) = y"); such constructs are bad as they can lead to
runtime exceptions.
Additionally, fix an existing such bad construct in a test case; we
workaround it by using error, since that should never fail.
Signed-off-by: Iustin Pop <iustin@google.com>
Reviewed-by: Guido Trotter <ultrotter@google.com>
---
Makefile.am | 7 ++++++-
configure.ac | 11 +++++++++++
htest/Test/Ganeti/HTools/Cluster.hs | 6 +++++-
3 files changed, 22 insertions(+), 2 deletions(-)
diff --git a/Makefile.am b/Makefile.am
index d6a0e28a0..7daf7788d 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -401,7 +401,12 @@ HS_ALL_PROGS = \
HS_PROG_SRCS = $(patsubst %,%.hs,$(HS_ALL_PROGS))
HS_BUILT_TEST_HELPERS = $(HS_BIN_ROLES:%=htest/%) htest/hail
-HFLAGS = -O -Wall -Werror -fwarn-monomorphism-restriction -fwarn-tabs -ihtools
+HFLAGS = \
+ -O -Wall -Werror -ihtools \
+ -fwarn-monomorphism-restriction \
+ -fwarn-tabs \
+ $(GHC_BYVERSION_FLAGS)
+
# extra flags that can be overriden on the command line (e.g. -Wwarn, etc.)
HEXTRA =
# internal extra flags (used for htest/test mainly)
diff --git a/configure.ac b/configure.ac
index 3e134a21d..1cc62d5df 100644
--- a/configure.ac
+++ b/configure.ac
@@ -430,6 +430,17 @@ if test -z "$GHC"; then
AC_MSG_FAILURE([ghc not found, compilation will not possible])
fi
+AC_MSG_CHECKING([checking for extra GHC flags])
+GHC_BYVERSION_FLAGS=""
+# check for GHC supported flags that vary accross versions
+for flag in -fwarn-incomplete-uni-patterns; do
+ if $GHC -e "0" $flag >/dev/null 2>/dev/null; then
+ GHC_BYVERSION_FLAGS="$GHC_BYVERSION_FLAGS $flag"
+ fi
+done
+AC_MSG_RESULT($GHC_BYVERSION_FLAGS)
+AC_SUBST(GHC_BYVERSION_FLAGS)
+
# Check for ghc-pkg
AC_ARG_VAR(GHC_PKG, [ghc-pkg path])
AC_PATH_PROG(GHC_PKG, [ghc-pkg], [])
diff --git a/htest/Test/Ganeti/HTools/Cluster.hs b/htest/Test/Ganeti/HTools/Cluster.hs
index fdc49240b..96bd1cf52 100644
--- a/htest/Test/Ganeti/HTools/Cluster.hs
+++ b/htest/Test/Ganeti/HTools/Cluster.hs
@@ -346,7 +346,11 @@ prop_AllocBalance =
prop_CheckConsistency :: Node.Node -> Instance.Instance -> Bool
prop_CheckConsistency node inst =
let nl = makeSmallCluster node 3
- [node1, node2, node3] = Container.elems nl
+ (node1, node2, node3) =
+ case Container.elems nl of
+ [a, b, c] -> (a, b, c)
+ l -> error $ "Invalid node list out of makeSmallCluster/3: " ++
+ show l
node3' = node3 { Node.group = 1 }
nl' = Container.add (Node.idx node3') node3' nl
inst1 = Instance.setBoth inst (Node.idx node1) (Node.idx node2)
--
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