Compile Java with Zinc

Added --compile-zinc-java-enabled to enable compilation of java targets with zinc.

Eventually we want to refactor everything around to choose a java compiler globally and hopefully retire jmake. For now as a proof of the concept added just a flag to enable it so everyone can test before futher changes.

Testing Done:
ci.sh passes: https://travis-ci.org/fkorotkov/pants/builds/61095655

Reviewed at https://rbcommons.com/s/twitter/r/2156/

src/python/pants/backend/jvm/register.py

@@ -37,7 +37,8 @@
 from pants.backend.jvm.tasks.junit_run import JUnitRun
 from pants.backend.jvm.tasks.jvm_compile.java.apt_compile import AptCompile
 from pants.backend.jvm.tasks.jvm_compile.java.java_compile import JavaCompile
-from pants.backend.jvm.tasks.jvm_compile.scala.scala_compile import ScalaCompile
+from pants.backend.jvm.tasks.jvm_compile.scala.scala_compile import (JavaZincCompile,
+                                                                     ScalaZincCompile)
 from pants.backend.jvm.tasks.jvm_run import JvmRun
 from pants.backend.jvm.tasks.nailgun_task import NailgunKillall
 from pants.backend.jvm.tasks.scala_repl import ScalaRepl
@@ -119,12 +120,13 @@ def register_goals():
   # however if the JavaCompile group member were registered earlier, it would claim the ScalaLibrary
   # targets with mixed source sets leaving those targets un-compiled by scalac and resulting in
   # systemic compile errors.
-  jvm_compile.add_member(ScalaCompile)
+  jvm_compile.add_member(ScalaZincCompile)
 
   # Its important we add AptCompile before JavaCompile since it 1st selector wins and apt code is a
   # subset of java code
   jvm_compile.add_member(AptCompile)
 
+  jvm_compile.add_member(JavaZincCompile)
   jvm_compile.add_member(JavaCompile)
 
   task(name='jvm', action=jvm_compile).install('compile').with_description('Compile source code.')

src/python/pants/backend/jvm/tasks/jvm_compile/scala/scala_compile.py

@@ -15,9 +15,7 @@
 from pants.option.options import Options
 
 
-class ScalaCompile(JvmCompile):
-  _language = 'scala'
-  _file_suffix = '.scala'
+class ZincCompile(JvmCompile):
   _supports_concurrent_execution = True
 
   @classmethod
@@ -34,7 +32,7 @@ def get_no_warning_args_default(cls):
 
   @classmethod
   def register_options(cls, register):
-    super(ScalaCompile, cls).register_options(register)
+    super(ZincCompile, cls).register_options(register)
     # Note: Used in ZincUtils.
     # TODO: Revisit this. It's unintuitive for ZincUtils to reach back into the task for options.
     register('--plugins', action='append', help='Use these scalac plugins.')
@@ -44,7 +42,7 @@ def register_options(cls, register):
     ZincUtils.register_options(register, cls.register_jvm_tool)
 
   def __init__(self, *args, **kwargs):
-    super(ScalaCompile, self).__init__(*args, **kwargs)
+    super(ZincCompile, self).__init__(*args, **kwargs)
 
     # Set up the zinc utils.
     color = self.get_options().colors
@@ -97,3 +95,28 @@ def extra_products(self, target):
   def compile(self, args, classpath, sources, classes_output_dir, upstream_analysis, analysis_file):
     return self._zinc_utils.compile(args, classpath, sources,
                                     classes_output_dir, analysis_file, upstream_analysis)
+
+class ScalaZincCompile(ZincCompile):
+  _language = 'scala'
+  _file_suffix = '.scala'
+
+class JavaZincCompile(ZincCompile):
+  _language = 'java'
+  _file_suffix = '.java'
+
+  @classmethod
+  def get_args_default(cls, bootstrap_option_values):
+    return super(JavaZincCompile, cls).get_args_default(bootstrap_option_values) + ('-java-only',)
+
+  @classmethod
+  def name(cls):
+    # Use a different name from 'java' so options from JMake version won't interfere.
+    return "zinc-java"
+
+  @classmethod
+  def register_options(cls, register):
+    super(JavaZincCompile, cls).register_options(register)
+    register('--enabled', action='store_true', default=False, help='Use zinc to compile Java targets')
+
+  def select(self, target):
+    return self.get_options().enabled and super(JavaZincCompile, self).select(target)

tests/python/pants_test/backend/jvm/tasks/jvm_compile/base_compile_integration_test.py

@@ -16,7 +16,7 @@
 class BaseCompileIT(PantsRunIntegrationTest):
   @contextmanager
   def do_test_compile(self, target, strategy,
-      expected_files=None, iterations=2, expect_failure=False):
+      expected_files=None, iterations=2, expect_failure=False, extra_args=None):
     """Runs a configurable number of iterations of compilation for the given target.
 
     By default, runs twice to shake out errors related to noops.
@@ -29,7 +29,7 @@ def do_test_compile(self, target, strategy,
             '--compile-java-strategy={}'.format(strategy),
             '--compile-scala-strategy={}'.format(strategy),
             target,
-          ]
+          ] + (extra_args if extra_args else [])
         # Clean-all on the first iteration.
         if i == 0:
           args.insert(0, 'clean-all')

tests/python/pants_test/backend/jvm/tasks/jvm_compile/java/BUILD

@@ -17,7 +17,6 @@ python_tests(
   ]
 )
 
-
 python_tests(
   name='apt_compile_integration',
   sources=['test_apt_compile_integration.py'],
@@ -26,6 +25,14 @@ python_tests(
   ]
 )
 
+python_tests(
+  name='java_zinc_compile_integration',
+  sources=['test_java_zinc_compile_integration.py'],
+  dependencies=[
+    'tests/python/pants_test/backend/jvm/tasks/jvm_compile:base_compile_integration_test',
+  ]
+)
+
 python_tests(
   name='java_compile_integration',
   sources=['test_java_compile_integration.py'],

tests/python/pants_test/backend/jvm/tasks/jvm_compile/java/test_java_zinc_compile_integration.py

@@ -0,0 +1,19 @@
+# coding=utf-8
+# Copyright 2015 Pants project contributors (see CONTRIBUTORS.md).
+# Licensed under the Apache License, Version 2.0 (see LICENSE).
+
+from __future__ import (absolute_import, division, generators, nested_scopes, print_function,
+                        unicode_literals, with_statement)
+
+from pants_test.backend.jvm.tasks.jvm_compile.base_compile_integration_test import BaseCompileIT
+from pants_test.backend.jvm.tasks.jvm_compile.utils import provide_compile_strategies
+
+
+class JvmExamplesCompileIntegrationTest(BaseCompileIT):
+  @provide_compile_strategies
+  def test_java_src_zinc_compile(self, strategy):
+    self.do_test_compile('examples/src/java/::', strategy, extra_args='--compile-zinc-java-enabled')
+
+  @provide_compile_strategies
+  def test_java_tests_zinc_compile(self, strategy):
+    self.do_test_compile('examples/tests/java/::', strategy, extra_args='--compile-zinc-java-enabled')