diff --git a/BUILDING.txt b/BUILDING.txt
index 39bb73b7b91..9c3c683dffa 100644
--- a/BUILDING.txt
+++ b/BUILDING.txt
@@ -345,3 +345,14 @@ http://www.zlib.net/
Building distributions:
* Build distribution with native code : mvn package [-Pdist][-Pdocs][-Psrc][-Dtar]
+
+----------------------------------------------------------------------------------
+Running compatibility checks with checkcompatibility.py
+
+Invoke `./dev-support/bin/checkcompatibility.py` to run Java API Compliance Checker
+to compare the public Java APIs of two git objects. This can be used by release
+managers to compare the compatibility of a previous and current release.
+
+As an example, this invocation will check the compatibility of interfaces annotated as Public or LimitedPrivate:
+
+./dev-support/bin/checkcompatibility.py --annotation org.apache.hadoop.classification.InterfaceAudience.Public --annotation org.apache.hadoop.classification.InterfaceAudience.LimitedPrivate --include "hadoop.*" branch-2.7.2 trunk
diff --git a/dev-support/bin/checkcompatibility.py b/dev-support/bin/checkcompatibility.py
new file mode 100755
index 00000000000..ad1e9cbe47f
--- /dev/null
+++ b/dev-support/bin/checkcompatibility.py
@@ -0,0 +1,345 @@
+#!/usr/bin/env python
+#
+# 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.
+
+# Script which checks Java API compatibility between two revisions of the
+# Java client.
+#
+# Originally sourced from Apache Kudu, which was based on the
+# compatibility checker from the Apache HBase project, but ported to
+# Python for better readability.
+
+import logging
+import os
+import re
+import shutil
+import subprocess
+import sys
+import urllib2
+try:
+ import argparse
+except ImportError:
+ sys.stderr.write("Please install argparse, e.g. via `pip install argparse`.")
+ sys.exit(2)
+
+# Various relative paths
+REPO_DIR = os.getcwd()
+
+def check_output(*popenargs, **kwargs):
+ r"""Run command with arguments and return its output as a byte string.
+ Backported from Python 2.7 as it's implemented as pure python on stdlib.
+ >>> check_output(['/usr/bin/python', '--version'])
+ Python 2.6.2
+ """
+ process = subprocess.Popen(stdout=subprocess.PIPE, *popenargs, **kwargs)
+ output, _ = process.communicate()
+ retcode = process.poll()
+ if retcode:
+ cmd = kwargs.get("args")
+ if cmd is None:
+ cmd = popenargs[0]
+ error = subprocess.CalledProcessError(retcode, cmd)
+ error.output = output
+ raise error
+ return output
+
+def get_repo_dir():
+ """ Return the path to the top of the repo. """
+ dirname, _ = os.path.split(os.path.abspath(__file__))
+ return os.path.join(dirname, "../..")
+
+def get_scratch_dir():
+ """ Return the path to the scratch dir that we build within. """
+ scratch_dir = os.path.join(get_repo_dir(), "target", "compat-check")
+ if not os.path.exists(scratch_dir):
+ os.makedirs(scratch_dir)
+ return scratch_dir
+
+def get_java_acc_dir():
+ """ Return the path where we check out the Java API Compliance Checker. """
+ return os.path.join(get_repo_dir(), "target", "java-acc")
+
+
+def clean_scratch_dir(scratch_dir):
+ """ Clean up and re-create the scratch directory. """
+ if os.path.exists(scratch_dir):
+ logging.info("Removing scratch dir %s...", scratch_dir)
+ shutil.rmtree(scratch_dir)
+ logging.info("Creating empty scratch dir %s...", scratch_dir)
+ os.makedirs(scratch_dir)
+
+
+def checkout_java_tree(rev, path):
+ """ Check out the Java source tree for the given revision into
+ the given path. """
+ logging.info("Checking out %s in %s", rev, path)
+ os.makedirs(path)
+ # Extract java source
+ subprocess.check_call(["bash", '-o', 'pipefail', "-c",
+ ("git archive --format=tar %s | " +
+ "tar -C \"%s\" -xf -") % (rev, path)],
+ cwd=get_repo_dir())
+
+def get_git_hash(revname):
+ """ Convert 'revname' to its SHA-1 hash. """
+ return check_output(["git", "rev-parse", revname],
+ cwd=get_repo_dir()).strip()
+
+def get_repo_name():
+ """Get the name of the repo based on the git remote."""
+ remotes = check_output(["git", "remote", "-v"],
+ cwd=get_repo_dir()).strip().split("\n")
+ # Example output:
+ # origin https://github.com/apache/hadoop.git (fetch)
+ # origin https://github.com/apache/hadoop.git (push)
+ remote_url = remotes[0].split("\t")[1].split(" ")[0]
+ remote = remote_url.split("/")[-1]
+ if remote.endswith(".git"):
+ remote = remote[:-4]
+ return remote
+
+def build_tree(java_path):
+ """ Run the Java build within 'path'. """
+ logging.info("Building in %s...", java_path)
+ subprocess.check_call(["mvn", "-DskipTests", "-Dmaven.javadoc.skip=true",
+ "package"],
+ cwd=java_path)
+
+
+def checkout_java_acc(force):
+ """
+ Check out the Java API Compliance Checker. If 'force' is true, will
+ re-download even if the directory exists.
+ """
+ acc_dir = get_java_acc_dir()
+ if os.path.exists(acc_dir):
+ logging.info("Java ACC is already downloaded.")
+ if not force:
+ return
+ logging.info("Forcing re-download.")
+ shutil.rmtree(acc_dir)
+
+ logging.info("Downloading Java ACC...")
+
+ url = "https://github.com/lvc/japi-compliance-checker/archive/1.8.tar.gz"
+ scratch_dir = get_scratch_dir()
+ path = os.path.join(scratch_dir, os.path.basename(url))
+ jacc = urllib2.urlopen(url)
+ with open(path, 'wb') as w:
+ w.write(jacc.read())
+
+ subprocess.check_call(["tar", "xzf", path],
+ cwd=scratch_dir)
+
+ shutil.move(os.path.join(scratch_dir, "japi-compliance-checker-1.8"),
+ os.path.join(acc_dir))
+
+
+def find_jars(path):
+ """ Return a list of jars within 'path' to be checked for compatibility. """
+ all_jars = set(check_output(["find", path, "-name", "*.jar"]).splitlines())
+
+ return [j for j in all_jars if (
+ "-tests" not in j and
+ "-sources" not in j and
+ "-with-dependencies" not in j)]
+
+def write_xml_file(path, version, jars):
+ """Write the XML manifest file for JACC."""
+ with open(path, "wt") as f:
+ f.write("" + version + "\n")
+ f.write("")
+ for j in jars:
+ f.write(j + "\n")
+ f.write("")
+
+def run_java_acc(src_name, src_jars, dst_name, dst_jars, annotations):
+ """ Run the compliance checker to compare 'src' and 'dst'. """
+ logging.info("Will check compatibility between original jars:\n\t%s\n" +
+ "and new jars:\n\t%s",
+ "\n\t".join(src_jars),
+ "\n\t".join(dst_jars))
+
+ java_acc_path = os.path.join(get_java_acc_dir(), "japi-compliance-checker.pl")
+
+ src_xml_path = os.path.join(get_scratch_dir(), "src.xml")
+ dst_xml_path = os.path.join(get_scratch_dir(), "dst.xml")
+ write_xml_file(src_xml_path, src_name, src_jars)
+ write_xml_file(dst_xml_path, dst_name, dst_jars)
+
+ out_path = os.path.join(get_scratch_dir(), "report.html")
+
+ args = ["perl", java_acc_path,
+ "-l", get_repo_name(),
+ "-d1", src_xml_path,
+ "-d2", dst_xml_path,
+ "-report-path", out_path]
+
+ if annotations is not None:
+ annotations_path = os.path.join(get_scratch_dir(), "annotations.txt")
+ with file(annotations_path, "w") as f:
+ for ann in annotations:
+ print >>f, ann
+ args += ["-annotations-list", annotations_path]
+
+ subprocess.check_call(args)
+
+def filter_jars(jars, include_filters, exclude_filters):
+ """Filter the list of JARs based on include and exclude filters."""
+ filtered = []
+ # Apply include filters
+ for j in jars:
+ found = False
+ basename = os.path.basename(j)
+ for f in include_filters:
+ if f.match(basename):
+ found = True
+ break
+ if found:
+ filtered += [j]
+ else:
+ logging.debug("Ignoring JAR %s", j)
+ # Apply exclude filters
+ exclude_filtered = []
+ for j in filtered:
+ basename = os.path.basename(j)
+ found = False
+ for f in exclude_filters:
+ if f.match(basename):
+ found = True
+ break
+ if found:
+ logging.debug("Ignoring JAR %s", j)
+ else:
+ exclude_filtered += [j]
+
+ return exclude_filtered
+
+
+def main():
+ """Main function."""
+ logging.basicConfig(level=logging.INFO)
+ parser = argparse.ArgumentParser(
+ description="Run Java API Compliance Checker.")
+ parser.add_argument("-f", "--force-download",
+ action="store_true",
+ help="Download dependencies (i.e. Java JAVA_ACC) " +
+ "even if they are already present")
+ parser.add_argument("-i", "--include-file",
+ action="append",
+ dest="include_files",
+ help="Regex filter for JAR files to be included. " +
+ "Applied before the exclude filters. " +
+ "Can be specified multiple times.")
+ parser.add_argument("-e", "--exclude-file",
+ action="append",
+ dest="exclude_files",
+ help="Regex filter for JAR files to be excluded. " +
+ "Applied after the include filters. " +
+ "Can be specified multiple times.")
+ parser.add_argument("-a", "--annotation",
+ action="append",
+ dest="annotations",
+ help="Fully-qualified Java annotation. " +
+ "Java ACC will only check compatibility of " +
+ "annotated classes. Can be specified multiple times.")
+ parser.add_argument("--skip-clean",
+ action="store_true",
+ help="Skip cleaning the scratch directory.")
+ parser.add_argument("--skip-build",
+ action="store_true",
+ help="Skip building the projects.")
+ parser.add_argument("src_rev", nargs=1, help="Source revision.")
+ parser.add_argument("dst_rev", nargs="?", default="HEAD",
+ help="Destination revision. " +
+ "If not specified, will use HEAD.")
+
+ if len(sys.argv) == 1:
+ parser.print_help()
+ sys.exit(1)
+
+ args = parser.parse_args()
+
+ src_rev, dst_rev = args.src_rev[0], args.dst_rev
+
+ logging.info("Source revision: %s", src_rev)
+ logging.info("Destination revision: %s", dst_rev)
+
+ # Construct the JAR regex patterns for filtering.
+ include_filters = []
+ if args.include_files is not None:
+ for f in args.include_files:
+ logging.info("Applying JAR filename include filter: %s", f)
+ include_filters += [re.compile(f)]
+ else:
+ include_filters = [re.compile(".*")]
+
+ exclude_filters = []
+ if args.exclude_files is not None:
+ for f in args.exclude_files:
+ logging.info("Applying JAR filename exclude filter: %s", f)
+ exclude_filters += [re.compile(f)]
+
+ # Construct the annotation list
+ annotations = args.annotations
+ if annotations is not None:
+ logging.info("Filtering classes using %d annotation(s):", len(annotations))
+ for a in annotations:
+ logging.info("\t%s", a)
+
+ # Download deps.
+ checkout_java_acc(args.force_download)
+
+ # Set up the build.
+ scratch_dir = get_scratch_dir()
+ src_dir = os.path.join(scratch_dir, "src")
+ dst_dir = os.path.join(scratch_dir, "dst")
+
+ if args.skip_clean:
+ logging.info("Skipping cleaning the scratch directory")
+ else:
+ clean_scratch_dir(scratch_dir)
+ # Check out the src and dst source trees.
+ checkout_java_tree(get_git_hash(src_rev), src_dir)
+ checkout_java_tree(get_git_hash(dst_rev), dst_dir)
+
+ # Run the build in each.
+ if args.skip_build:
+ logging.info("Skipping the build")
+ else:
+ build_tree(src_dir)
+ build_tree(dst_dir)
+
+ # Find the JARs.
+ src_jars = find_jars(src_dir)
+ dst_jars = find_jars(dst_dir)
+
+ # Filter the JARs.
+ src_jars = filter_jars(src_jars, include_filters, exclude_filters)
+ dst_jars = filter_jars(dst_jars, include_filters, exclude_filters)
+
+ if len(src_jars) == 0 or len(dst_jars) == 0:
+ logging.error("No JARs found! Are your filters too strong?")
+ sys.exit(1)
+
+ run_java_acc(src_rev, src_jars,
+ dst_rev, dst_jars, annotations)
+
+
+if __name__ == "__main__":
+ main()