Added cache clear to e2e scripts (#2400)

* Added cache clear to e2e scripts

* Install latest yarn on AppVeyor to avoid windows crashing bug in yarn

* Alternative fix for yarn crashing e2e tests on windows machines

tasks/e2e-installs.sh

@@ -83,6 +83,30 @@ set -x
 cd ..
 root_path=$PWD
 
+# Clear cache to avoid issues with incorrect packages being used
+if hash yarnpkg 2>/dev/null
+then
+  # AppVeyor uses an old version of yarn.
+  # Once updated to 0.24.3 or above, the workaround can be removed
+  # and replaced with `yarnpkg cache clean`
+  # Issues: 
+  #    https://github.com/yarnpkg/yarn/issues/2591
+  #    https://github.com/appveyor/ci/issues/1576
+  #    https://github.com/facebookincubator/create-react-app/pull/2400
+  # When removing workaround, you may run into
+  #    https://github.com/facebookincubator/create-react-app/issues/2030
+  case "$(uname -s)" in
+    *CYGWIN*|MSYS*|MINGW*) yarn=yarn.cmd;;
+    *) yarn=yarnpkg;;
+  esac
+  $yarn cache clean
+fi
+
+if hash npm 2>/dev/null
+then
+  npm cache clean
+fi
+
 # Prevent lerna bootstrap, we only want top-level dependencies
 cp package.json package.json.bak
 grep -v "lerna bootstrap" package.json > temp && mv temp package.json

tasks/e2e-kitchensink.sh

@@ -66,6 +66,30 @@ set -x
 cd ..
 root_path=$PWD
 
+# Clear cache to avoid issues with incorrect packages being used
+if hash yarnpkg 2>/dev/null
+then
+  # AppVeyor uses an old version of yarn.
+  # Once updated to 0.24.3 or above, the workaround can be removed
+  # and replaced with `yarnpkg cache clean`
+  # Issues: 
+  #    https://github.com/yarnpkg/yarn/issues/2591
+  #    https://github.com/appveyor/ci/issues/1576
+  #    https://github.com/facebookincubator/create-react-app/pull/2400
+  # When removing workaround, you may run into
+  #    https://github.com/facebookincubator/create-react-app/issues/2030
+  case "$(uname -s)" in
+    *CYGWIN*|MSYS*|MINGW*) yarn=yarn.cmd;;
+    *) yarn=yarnpkg;;
+  esac
+  $yarn cache clean
+fi
+
+if hash npm 2>/dev/null
+then
+  npm cache clean
+fi
+
 # Prevent lerna bootstrap, we only want top-level dependencies
 cp package.json package.json.bak
 grep -v "lerna bootstrap" package.json > temp && mv temp package.json

tasks/e2e-simple.sh

@@ -65,6 +65,30 @@ set -x
 cd ..
 root_path=$PWD
 
+# Clear cache to avoid issues with incorrect packages being used
+if hash yarnpkg 2>/dev/null
+then
+  # AppVeyor uses an old version of yarn.
+  # Once updated to 0.24.3 or above, the workaround can be removed
+  # and replaced with `yarnpkg cache clean`
+  # Issues: 
+  #    https://github.com/yarnpkg/yarn/issues/2591
+  #    https://github.com/appveyor/ci/issues/1576
+  #    https://github.com/facebookincubator/create-react-app/pull/2400
+  # When removing workaround, you may run into
+  #    https://github.com/facebookincubator/create-react-app/issues/2030
+  case "$(uname -s)" in
+    *CYGWIN*|MSYS*|MINGW*) yarn=yarn.cmd;;
+    *) yarn=yarnpkg;;
+  esac
+  $yarn cache clean
+fi
+
+if hash npm 2>/dev/null
+then
+  npm cache clean
+fi
+
 # Prevent lerna bootstrap, we only want top-level dependencies
 cp package.json package.json.bak
 grep -v "lerna bootstrap" package.json > temp && mv temp package.json