[FLINK-1166] Add qa-check.sh tool

The ./tools/qa-check.sh tool allows developers to check for common errors before opening a pull request.
The qa-checks are designed to be easily extensible by further checks.

This closes apache#366

pom.xml

@@ -1075,7 +1075,9 @@ under the License.
 				<configuration>
 					<source>1.6</source>
 					<target>1.6</target>
-					<!-- High optimization, no debugging <compilerArgument>-g:none -O</compilerArgument> -->
+					<!-- The output of Xlint is not show by default, but we activate it for the QA bot
+					to be able to get more warnings -->
+					<compilerArgument>-Xlint:all</compilerArgument>
 				</configuration>
 			</plugin>
 			<plugin>

tools/.gitignore

@@ -1 +1,2 @@
-merge_pull_request.sh
+_qa_workdir
+merge_pull_request.sh

tools/qa-check.sh

@@ -0,0 +1,175 @@
+#!/usr/bin/env bash
+
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You under the Apache License, Version 2.0
+# (the "License"); you may not use this file except in compliance with
+# the License.  You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+
+#
+# QA check your changes.
+# Possible options:
+# BRANCH set a another branch as the "check" reference
+#
+#
+# Use the tool like this "BRANCH=release-0.8 ./tools/qa-check.sh"
+#
+
+
+BRANCH=${BRANCH:-origin/master}
+
+
+
+here="`dirname \"$0\"`"				# relative
+here="`( cd \"$here\" && pwd )`" 	# absolutized and normalized
+if [ -z "$here" ] ; then
+	# error; for some reason, the path is not accessible
+	# to the script (e.g. permissions re-evaled after suid)
+	exit 1  # fail
+fi
+flink_home="`dirname \"$here\"`"
+
+cd $here
+
+if [ ! -d  "_qa_workdir" ] ; then
+	echo "_qa_workdir doesnt exist. Creating it"
+	mkdir _qa_workdir
+fi
+
+cd _qa_workdir
+
+if [ ! -d  "flink" ] ; then
+	echo "There is no flink copy in the workdir. Cloning flink"
+	git clone http://git-wip-us.apache.org/repos/asf/flink.git flink
+fi
+
+cd flink
+# fetch and checkout quietly
+git fetch -q origin
+git checkout -q $BRANCH
+cd $here
+# go to refrence flink directory
+
+cd _qa_workdir
+VAR_DIR=`pwd`
+cd flink
+
+# Initialize variables
+export TESTS_PASSED=true
+export MESSAGES="Flink QA-Check results:"$'\n'
+
+goToTestDirectory() {
+	cd $flink_home
+}
+
+############################ Methods ############################
+
+############ Javadocs ############
+JAVADOC_MVN_COMMAND="mvn javadoc:aggregate -Pdocs-and-source -Dmaven.javadoc.failOnError=false -Dquiet=false | grep  \"WARNING\|warning\|error\" | wc -l"
+
+referenceJavadocsErrors() {
+	eval $JAVADOC_MVN_COMMAND > "$VAR_DIR/_JAVADOCS_NUM_WARNINGS"
+}
+
+
+checkJavadocsErrors() {
+	OLD_JAVADOC_ERR_CNT=`cat $VAR_DIR/_JAVADOCS_NUM_WARNINGS` 
+	NEW_JAVADOC_ERR_CNT=`eval $JAVADOC_MVN_COMMAND`
+	if [ "$NEW_JAVADOC_ERR_CNT" -gt "$OLD_JAVADOC_ERR_CNT" ]; then
+		MESSAGES+=":-1: The change increases the number of javadoc errors from $OLD_JAVADOC_ERR_CNT to $NEW_JAVADOC_ERR_CNT"$'\n'
+		TESTS_PASSED=false
+	else
+		MESSAGES+=":+1: The number of javadoc errors was $OLD_JAVADOC_ERR_CNT and is now $NEW_JAVADOC_ERR_CNT"$'\n'
+	fi
+}
+
+
+############ Compiler warnings ############
+COMPILER_WARN_MVN_COMMAND="mvn clean compile -Dmaven.compiler.showWarning=true -Dmaven.compiler.showDeprecation=true | grep \"WARNING\""
+referenceCompilerWarnings() {
+	eval "$COMPILER_WARN_MVN_COMMAND | tee $VAR_DIR/_COMPILER_REFERENCE_WARNINGS | wc -l" > "$VAR_DIR/_COMPILER_NUM_WARNINGS"
+}
+
+checkCompilerWarnings() {
+	OLD_COMPILER_ERR_CNT=`cat $VAR_DIR/_COMPILER_NUM_WARNINGS` 
+	NEW_COMPILER_ERR_CNT=`eval $COMPILER_WARN_MVN_COMMAND | tee $VAR_DIR/_COMPILER_NEW_WARNINGS | wc -l`
+	if [ "$NEW_COMPILER_ERR_CNT" -gt "$OLD_COMPILER_ERR_CNT" ]; then
+		MESSAGES+=":-1: The change increases the number of compiler warnings from $OLD_COMPILER_ERR_CNT to $NEW_COMPILER_ERR_CNT"$'\n'
+		MESSAGES+='```diff'$'\n'
+		MESSAGES+=`diff $VAR_DIR/_COMPILER_REFERENCE_WARNINGS $VAR_DIR/_COMPILER_NEW_WARNINGS`$'\n'
+		MESSAGES+='```'$'\n'
+		TESTS_PASSED=false
+	else
+		MESSAGES+=":+1: The number of compiler warnings was $OLD_COMPILER_ERR_CNT and is now $NEW_COMPILER_ERR_CNT"$'\n'
+	fi
+}
+
+############ Files in lib ############
+BUILD_MVN_COMMAND="mvn clean package -DskipTests -Dmaven.javadoc.skip=true"
+COUNT_LIB_FILES="find . | grep \"\/lib\/\" | grep -v \"_qa_workdir\" | wc -l"
+referenceLibFiles() {
+	eval $BUILD_MVN_COMMAND > /dev/null
+	eval $COUNT_LIB_FILES > "$VAR_DIR/_NUM_LIB_FILES"
+}
+
+checkLibFiles() {
+	OLD_LIB_FILES_CNT=`cat $VAR_DIR/_NUM_LIB_FILES` 
+	eval $BUILD_MVN_COMMAND > /dev/null
+	NEW_LIB_FILES_CNT=`eval $COUNT_LIB_FILES`
+	if [ "$NEW_LIB_FILES_CNT" -gt "$OLD_LIB_FILES_CNT" ]; then
+		MESSAGES+=":-1: The change increases the number of dependencies in the lib/ folder from $OLD_LIB_FILES_CNT to $NEW_LIB_FILES_CNT"$'\n'
+		TESTS_PASSED=false
+	else
+		MESSAGES+=":+1: The number of files in the lib/ folder was $OLD_LIB_FILES_CNT before the change and is now $NEW_LIB_FILES_CNT"$'\n'
+	fi
+}
+
+############ @author tag ############
+
+checkAuthorTag() {
+	# we are grep-ing for "java" but we've messed up the string a bit so that it doesn't find exactly this line.
+	if [ `grep -r "@author" . | grep "ja""va" | wc -l` -gt "0" ]; then
+		MESSAGES+=":-1: The change contains @author tags"$'\n'
+		TESTS_PASSED=false
+	fi
+}
+
+
+################################### QA checks ###################################
+
+##### Methods to be executed on the current 'master'
+referenceJavadocsErrors
+referenceCompilerWarnings
+referenceLibFiles
+
+
+goToTestDirectory
+## Methods to be executed on the changes (flink root dir)
+checkJavadocsErrors
+checkCompilerWarnings
+checkLibFiles
+checkAuthorTag
+
+
+MESSAGES+=$'\n'"Test finished."$'\n'
+if [ "$TESTS_PASSED" == "true" ]; then
+	MESSAGES+="Overall result: :+1:. All tests passed"$'\n'
+else 
+	MESSAGES+="Overall result: :-1:. Some tests failed. Please check messages above"$'\n'
+fi
+
+echo "$MESSAGES"
+
+