Check API changes

paddle/scripts/paddle_build.sh

@@ -312,6 +312,20 @@ EOF
     fi
 }
 
+function assert_api_not_changed() {
+    mkdir -p ${PADDLE_ROOT}/build/.check_api_workspace
+    cd ${PADDLE_ROOT}/build/.check_api_workspace
+    virtualenv .env
+    source .env/bin/activate
+    pip install ${PADDLE_ROOT}/build/python/dist/*whl
+    curl ${PADDLE_API_SPEC_URL:-https://raw.githubusercontent.com/reyoung/FluidAPISpec/master/API.spec} \
+        > origin.spec
+    python ${PADDLE_ROOT}/tools/print_signatures.py paddle.fluid > new.spec
+    python ${PADDLE_ROOT}/tools/diff_api.py origin.spec new.spec
+    deactivate
+}
+
+
 function single_test() {
     TEST_NAME=$1
     if [ -z "${TEST_NAME}" ]; then
@@ -550,6 +564,7 @@ function main() {
       cicheck)
         cmake_gen ${PYTHON_ABI:-""}
         build
+        assert_api_not_changed
         run_test
         gen_capi_package
         gen_fluid_inference_lib

tools/diff_api.py

+#!/usr/bin/env python
+from __future__ import print_function
+import difflib
+import sys
+
+with open(sys.argv[1], 'r') as f:
+    origin = f.read()
+    origin = origin.splitlines()
+
+with open(sys.argv[2], 'r') as f:
+    new = f.read()
+    new = new.splitlines()
+
+differ = difflib.Differ()
+result = differ.compare(origin, new)
+
+error = False
+print('API Difference is: ')
+for each_diff in result:
+    if each_diff[0] in ['-', '?']:  # delete or change API is not allowed
+        error = True
+    elif each_diff[0] == '+':
+        # only new layers is allowed.
+        if not each_diff.startswith('+ paddle.fluid.layers.'):
+            error = True
+
+    if each_diff[0] != ' ':
+        print(each_diff)
+
+if error:
+    sys.exit(1)