Fixed errors in how arguments are passed to wire_gen.

Arguments such as 'roots' and 'enum_options' are expected to
be comma-delimited when multiple arguments exist, not added by repeated
specifications of the --roots or --enum_options flags.

Testing Done:
Wire_integration tests (including new test for --roots) pass.

CI went green here: https://travis-ci.org/pantsbuild/pants/builds/66615227

Bugs closed: 1664

Reviewed at https://rbcommons.com/s/twitter/r/2354/

examples/src/java/org/pantsbuild/example/wire/roots/BUILD

@@ -0,0 +1,12 @@
+# Copyright 2015 Pants project contributors (see CONTRIBUTORS.md).
+# Licensed under the Apache License, Version 2.0 (see LICENSE).
+
+jvm_binary(name='roots',
+  basename='wire-roots-example',
+  dependencies=[
+    'examples/src/wire/org/pantsbuild/example/roots',
+  ],
+  source='WireRootsExample.java',
+  main='org.pantsbuild.example.wire.roots.WireRootsExample',
+)
+

examples/src/java/org/pantsbuild/example/wire/roots/WireRootsExample.java

@@ -0,0 +1,10 @@
+// Copyright 2015 Pants project contributors (see CONTRIBUTORS.md).
+// Licensed under the Apache License, Version 2.0 (see LICENSE).
+
+package org.pantsbuild.example.wire.roots;
+
+class WireRootsExample {
+
+  public static void main(String[] args) {
+  }
+}

examples/src/wire/org/pantsbuild/example/roots/BUILD

@@ -0,0 +1,16 @@
+# Copyright 2015 Pants project contributors (see CONTRIBUTORS.md).
+# Licensed under the Apache License, Version 2.0 (see LICENSE).
+
+java_wire_library(name='roots',
+  sources=[
+    'foo.proto',
+    'bar.proto',
+    'foobar.proto',
+  ],
+  dependencies=[],
+  roots = [
+    'org.pantsbuild.example.roots.Bar',
+    'org.pantsbuild.example.roots.Foobar',
+    'org.pantsbuild.example.roots.Fooboo',
+  ],
+)

examples/src/wire/org/pantsbuild/example/roots/bar.proto

@@ -0,0 +1,9 @@
+// Copyright 2015 Pants project contributors (see CONTRIBUTORS.md).
+// Licensed under the Apache License, Version 2.0 (see LICENSE).
+
+package org.pantsbuild.example.roots;
+
+message Bar {
+  optional string param1 = 1;
+  optional string param2 = 2;
+}

examples/src/wire/org/pantsbuild/example/roots/foo.proto

@@ -0,0 +1,9 @@
+// Copyright 2015 Pants project contributors (see CONTRIBUTORS.md).
+// Licensed under the Apache License, Version 2.0 (see LICENSE).
+
+package org.pantsbuild.example.roots;
+
+message Foo {
+  optional string param1 = 1;
+  optional string param2 = 2;
+}

examples/src/wire/org/pantsbuild/example/roots/foobar.proto

@@ -0,0 +1,20 @@
+// Copyright 2015 Pants project contributors (see CONTRIBUTORS.md).
+// Licensed under the Apache License, Version 2.0 (see LICENSE).
+
+package org.pantsbuild.example.roots;
+
+message Foobar {
+  optional string param = 1;
+}
+
+message Barfoo {
+  optional string param = 1;
+}
+
+message Fooboo {
+  optional string param = 1;
+}
+
+message Farbar {
+  required string param = 1;
+}

src/python/pants/backend/codegen/targets/java_wire_library.py

@@ -6,7 +6,6 @@
                         unicode_literals, with_statement)
 
 import logging
-from textwrap import dedent
 
 from pants.backend.jvm.targets.exportable_jvm_library import ExportableJvmLibrary
 from pants.base.payload import Payload
@@ -50,12 +49,6 @@ def __init__(self,
 
     if service_writer_options:
       logger.warn('The service_writer_options flag is ignored.')
-    if roots:
-      logger.warn(dedent('''
-          It is known that passing in roots may not work as intended. Pants tries to predict what
-          files Wire will generate then does a verification to see if all of those files were
-          generated.  With the roots flag set, it may be the case that not all predicted files will
-          be generated and the verification will fail.'''))
 
     super(JavaWireLibrary, self).__init__(payload=payload, **kwargs)
     self.add_labels('codegen')

src/python/pants/backend/codegen/tasks/wire_gen.py

@@ -110,11 +110,11 @@ def execute_codegen(self, targets):
       if registry_class:
         args.append('--registry_class={0}'.format(registry_class))
 
-      for root in target.payload.roots:
-        args.append('--roots={0}'.format(root))
+      if target.payload.roots:
+        args.append('--roots={0}'.format(','.join(target.payload.roots)))
 
-      for enum_option in target.payload.enum_options:
-        args.append('--enum_options={0}'.format(enum_option))
+      if target.payload.enum_options:
+        args.append('--enum_options={0}'.format(','.join(target.payload.enum_options)))
 
       args.append('--proto_path={0}'.format(os.path.join(get_buildroot(),
                                                          SourceRoot.find(target))))

tests/python/pants_test/tasks/test_wire_integration.py

@@ -10,6 +10,7 @@
 import subprocess
 
 from pants.base.build_environment import get_buildroot
+from pants.util.contextutil import open_zip
 from pants_test.pants_run_integration_test import PantsRunIntegrationTest
 
 
@@ -76,3 +77,23 @@ def test_bundle_wire_dependent_targets(self):
     self.assertIn('Compound{name=Water, primary_element=Element{symbol=O, name=Oxygen, '
                   'atomic_number=8}, secondary_element=Element{symbol=H, name=Hydrogen, '
                   'atomic_number=1}}', java_out)
+
+  def test_compile_wire_roots(self):
+    pants_run = self.run_pants(['bundle', '--deployjar',
+                                'examples/src/java/org/pantsbuild/example/wire/roots'])
+    self.assert_success(pants_run)
+    out_path = os.path.join(get_buildroot(), 'dist', 'wire-roots-example.jar')
+    with open_zip(out_path) as zipfile:
+      jar_entries = zipfile.namelist()
+
+    def is_relevant(entry):
+      return (entry.startswith('org/pantsbuild/example/roots/') and entry.endswith('.class')
+              and '$' not in entry)
+
+    expected_classes = {
+      'org/pantsbuild/example/roots/Bar.class',
+      'org/pantsbuild/example/roots/Foobar.class',
+      'org/pantsbuild/example/roots/Fooboo.class',
+    }
+    received_classes = {entry for entry in jar_entries if is_relevant(entry)}
+    self.assertEqual(expected_classes, received_classes)