Cache dependencies

.travis.yml

@@ -1,39 +1,84 @@
-language: haskell
+# This file is based on a generated file.
+# See https://github.com/hvr/multi-ghc-travis.
+
+language: c
 
 sudo: false
 
+cache:
+  directories:
+    - $HOME/.cabsnap
+    - $HOME/.cabal/packages
+
+before_cache:
+  - rm -fv $HOME/.cabal/packages/hackage.haskell.org/build-reports.log
+  - rm -fv $HOME/.cabal/packages/hackage.haskell.org/00-index.tar
+
 matrix:
   include:
-    - env: CABALVER=1.20 GHCVER=7.6.3
+    - env: CABALVER=1.16 GHCVER=7.6.3
+      compiler: ": #GHC 7.6.3"
       addons: {apt: {packages: [cabal-install-1.16,ghc-7.6.3], sources: [hvr-ghc]}}
-    - env: CABALVER=1.20 GHCVER=7.8.4
+    - env: CABALVER=1.18 GHCVER=7.8.4
+      compiler: ": #GHC 7.8.4"
       addons: {apt: {packages: [cabal-install-1.18,ghc-7.8.4], sources: [hvr-ghc]}}
-    - env: CABALVER=1.22 GHCVER=7.10.1
-      addons: {apt: {packages: [cabal-install-1.22,ghc-7.10.1], sources: [hvr-ghc]}}
+    - env: CABALVER=1.22 GHCVER=7.10.2
+      compiler: ": #GHC 7.10.2"
+      addons: {apt: {packages: [cabal-install-1.22,ghc-7.10.2],sources: [hvr-ghc]}}
     - env: CABALVER=head GHCVER=head
+      compiler: ": #GHC HEAD"
       addons: {apt: {packages: [cabal-install-head,ghc-head],  sources: [hvr-ghc]}}
+
   allow_failures:
     - env: CABALVER=head GHCVER=head
 
 before_install:
+  - unset CC
   - export PATH=/opt/ghc/$GHCVER/bin:/opt/cabal/$CABALVER/bin:$PATH
 
 install:
-  - cabal update
-  - cabal sandbox init
-  - cabal install --only-dependencies --enable-tests --enable-benchmarks -j2
+  - cabal --version
+  - echo "$(ghc --version) [$(ghc --print-project-git-commit-id 2> /dev/null || echo '?')]"
+  - if [ -f $HOME/.cabal/packages/hackage.haskell.org/00-index.tar.gz ];
+    then
+      zcat $HOME/.cabal/packages/hackage.haskell.org/00-index.tar.gz >
+           $HOME/.cabal/packages/hackage.haskell.org/00-index.tar;
+    fi
+  - travis_retry cabal update -v
+  - sed -i 's/^jobs:/-- jobs:/' ${HOME}/.cabal/config
+  - cabal install --only-dependencies --enable-tests --dry -v > installplan.txt
+  - sed -i -e '1,/^Resolving /d' installplan.txt; cat installplan.txt
+
+  # check whether current requested install-plan matches cached package-db snapshot
+  - if diff -u installplan.txt $HOME/.cabsnap/installplan.txt;
+    then
+      echo "cabal build-cache HIT";
+      rm -rfv .ghc;
+      cp -a $HOME/.cabsnap/ghc $HOME/.ghc;
+      cp -a $HOME/.cabsnap/lib $HOME/.cabsnap/share $HOME/.cabsnap/bin $HOME/.cabal/;
+    else
+      echo "cabal build-cache MISS";
+      rm -rf $HOME/.cabsnap;
+      mkdir -p $HOME/.ghc $HOME/.cabal/lib $HOME/.cabal/share $HOME/.cabal/bin;
+      cabal install --only-dependencies --enable-tests;
+    fi
+
+  # snapshot package-db on cache miss
+  - if [ ! -d $HOME/.cabsnap ];
+    then
+       echo "snapshotting package-db to build-cache";
+       mkdir $HOME/.cabsnap;
+       cp -a $HOME/.ghc $HOME/.cabsnap/ghc;
+       cp -a $HOME/.cabal/lib $HOME/.cabal/share $HOME/.cabal/bin installplan.txt $HOME/.cabsnap/;
+    fi
 
 script:
- - cabal configure --enable-tests --enable-benchmarks -v2
- - cabal build -j2
- - cabal test
- - cabal check
- - cabal sdist
- - export SRC_TGZ=$(cabal info . | awk '{print $2 ".tar.gz";exit}') ;
-   cd dist/;
-   if [ -f "$SRC_TGZ" ]; then
-      cabal install --force-reinstalls "$SRC_TGZ";
-   else
-      echo "expected '$SRC_TGZ' not found";
-      exit 1;
-   fi
+  - if [ -f configure.ac ]; then autoreconf -i; fi
+  - cabal configure --enable-tests -v2
+  - cabal build
+  - cabal test
+  - cabal check
+  - cabal sdist
+
+  - SRC_TGZ=$(cabal info . | awk '{print $2;exit}').tar.gz &&
+    (cd dist && cabal install --force-reinstalls "$SRC_TGZ")