Check for SDK error regressions on presubmit

tool/build_sdk.sh

Index: tool/build_sdk.sh
diff --git a/tool/build_sdk.sh b/tool/build_sdk.sh
index eebaf22d905fd5766c6aca33b360d42a48bc1654..fca5810b8b7354f61ab62d8c3e9ba0f46d4e27ce 100755
--- a/tool/build_sdk.sh
+++ b/tool/build_sdk.sh
@@ -13,8 +13,17 @@ if [[ -d lib/runtime/dart ]] ; then
 fi
 
 # TODO(jmesserly): for now we're suppressing errors in SDK compilation
-dart -c bin/devc.dart --no-source-maps --sdk-check --force-compile -l shout \
-    --dart-sdk test/generated_sdk -o lib/runtime/ dart:core || true
+mkdir -p test/generated_sdk/actual

[Leaf, 2015/05/28 16:01:38]

What is this for?  The actual directory doesn't seem to be used by the commands
below, unless it's implicit somewhere?

[vsm, 2015/05/28 16:15:03]

Removed.  Vestige of previous version.  Thanks for the catch.

+dart -c bin/devc.dart --no-source-maps --sdk-check --force-compile -l warning \
+    --dart-sdk test/generated_sdk -o lib/runtime/ dart:core \
+    > test/generated_sdk/sdk_errors.txt || true
+
+if ! diff tool/sdk_expected_errors.txt test/generated_sdk/sdk_errors.txt ; then
+    echo
+    echo 'SDK errors have changed.  To update expectations, run:'
+    echo '$ cp test/generated_sdk/sdk_errors.txt tool/sdk_expected_errors.txt'
+    exit 1
+fi
 
 if [[ ! -f lib/runtime/dart/core.js ]] ; then
     echo 'core.js not found, assuming build failed.'