Core: improve build_release.py

Don't insist on log file removal until after usage is printed.

Some simple Python code improvements (x.find(y) != -1 --> y in x)

Make sure the git area is "clean" (has no unpushed changes, has pulled
all changes, has no untracked files)

Add label color detail when creating next github version label.

Closes elastic#7913

dev-tools/build_release.py

@@ -28,6 +28,7 @@
 import fnmatch
 import socket
 import urllib.request
+import subprocess
 
 from http.client import HTTPConnection
 from http.client import HTTPSConnection
@@ -67,8 +68,6 @@
            ('head', 'mobz/elasticsearch-head')]
 
 LOG = env.get('ES_RELEASE_LOG', '/tmp/elasticsearch_release.log')
-if os.path.exists(LOG):
-  raise RuntimeError('please remove old release log %s first' % LOG)
 
 def log(msg):
   log_plain('\n%s' % msg)
@@ -115,14 +114,14 @@ def java_exe():
 
 def verify_java_version(version):
   s = os.popen('%s; java -version 2>&1' % java_exe()).read()
-  if s.find(' version "%s.' % version) == -1:
+  if ' version "%s.' % version not in s:
     raise RuntimeError('got wrong version for java %s:\n%s' % (version, s))
 
 # Verifies the java version. We guarantee that we run with Java 1.7
 # If 1.7 is not available fail the build!
 def verify_mvn_java_version(version, mvn):
   s = os.popen('%s; %s --version 2>&1' % (java_exe(), mvn)).read()
-  if s.find('Java version: %s' % version) == -1:
+  if 'Java version: %s' % version not in s:
     raise RuntimeError('got wrong java version for %s %s:\n%s' % (mvn, version, s))
 
 # Returns the hash of the current git HEAD revision
@@ -311,7 +310,7 @@ def wait_for_node_startup(host='127.0.0.1', port=9200,timeout=15):
 # Ensures we are using a true Lucene release, not a snapshot build:
 def verify_lucene_version():
   s = open('pom.xml', encoding='utf-8').read()
-  if s.find('download.elasticsearch.org/lucenesnapshots') != -1:
+  if 'download.elasticsearch.org/lucenesnapshots' in s:
     raise RuntimeError('pom.xml contains download.elasticsearch.org/lucenesnapshots repository: remove that before releasing')
 
   m = re.search(r'<lucene.version>(.*?)</lucene.version>', s)
@@ -545,9 +544,32 @@ def find_bwc_version(release_version, bwc_dir='backwards'):
     log('  bwc directory [%s] does not exists or is not a directory - skipping' % bwc_dir)
   return bwc_version
 
+def ensure_checkout_is_clean(branchName):
+  # Make sure no local mods:
+  s = subprocess.check_output('git diff --shortstat', shell=True)
+  if len(s) > 0:
+    raise RuntimeError('git diff --shortstat is non-empty: got:\n%s' % s)
+
+  # Make sure no untracked files:
+  s = subprocess.check_output('git status', shell=True)
+  if 'Untracked files:' in s:
+    raise RuntimeError('git status shows untracked files: got:\n%s' % s)
+
+  # Make sure we are on the right branch (NOTE: a bit weak, since we default to current branch):
+  if 'On branch %s' % branchName not in s:
+    raise RuntimeError('git status does not show branch %s: got:\n%s' % (branchName, s))
+
+  # Make sure we have all changes from origin:
+  if 'is behind' in s:
+    raise RuntimeError('git status shows not all changes pulled from origin; try running "git pull origin %s": got:\n%s' % (branchName, s))
+
+  # Make sure we no local unpushed changes (this is supposed to be a clean area):
+  if 'is ahead' in s:
+    raise RuntimeError('git status shows local commits; try running "git fetch origin", "git checkout %s", "git reset --hard origin/%s": got:\n%s' % (branchName, branchName, s))
+
 if __name__ == '__main__':
   parser = argparse.ArgumentParser(description='Builds and publishes a Elasticsearch Release')
-  parser.add_argument('--branch', '-b', metavar='master', default=get_current_branch(),
+  parser.add_argument('--branch', '-b', metavar='RELEASE_BRANCH', default=get_current_branch(),
                        help='The branch to release from. Defaults to the current branch.')
   parser.add_argument('--cpus', '-c', metavar='1', default=1,
                        help='The number of cpus to use for running the test. Default is [1]')
@@ -574,6 +596,10 @@ def find_bwc_version(release_version, bwc_dir='backwards'):
   cpus = args.cpus
   build = not args.smoke
   smoke_test_version = args.smoke
+
+  if os.path.exists(LOG):
+    raise RuntimeError('please remove old release log %s first' % LOG)
+
   if not dry_run:
     check_s3_credentials()
     print('WARNING: dryrun is set to "false" - this will push and publish the release')
@@ -584,6 +610,7 @@ def find_bwc_version(release_version, bwc_dir='backwards'):
   print('  JAVA_HOME is [%s]' % JAVA_HOME)
   print('  Running with maven command: [%s] ' % (MVN))
   if build:
+    ensure_checkout_is_clean(src_branch)
     verify_lucene_version()
     release_version = find_release_version(src_branch)
     ensure_no_open_tickets(release_version)
@@ -633,8 +660,7 @@ def find_bwc_version(release_version, bwc_dir='backwards'):
         cherry_pick_command = ' and cherry-pick the documentation changes: \'git cherry-pick %s\' to the development branch' % (version_head_hash)
       pending_msg = """
       Release successful pending steps:
-        * create a version tag on github for version 'v%(version)s'
-        * check if there are pending issues for this version (https://github.com/elasticsearch/elasticsearch/issues?labels=v%(version)s&page=1&state=open)
+        * create a new vX.Y.Z label on github for the next release, with label color #dddddd (https://github.com/elasticsearch/elasticsearch/labels)
         * publish the maven artifacts on Sonatype: https://oss.sonatype.org/index.html
            - here is a guide: https://docs.sonatype.org/display/Repository/Sonatype+OSS+Maven+Repository+Usage+Guide#SonatypeOSSMavenRepositoryUsageGuide-8a.ReleaseIt
         * check if the release is there https://oss.sonatype.org/content/repositories/releases/org/elasticsearch/elasticsearch/%(version)s