[jvm-compile] Copy compile classpath into runtime classpath even if a…

…lready defined (#4310)

#Problem
In #4309, the problem was caused by jvm_compile assuming it is always first in the compile order. 

#Solution

This patch ensures the compile_classpath is mixed into the runtime classpath even if it has already been initialized.

#Result

Fixes #4309

src/python/pants/backend/jvm/tasks/classpath_products.py

@@ -305,6 +305,15 @@ def get_internal_classpath_entries_for_targets(self, targets, respect_excludes=T
     return [(conf, cp_entry) for conf, cp_entry in classpath_tuples
             if ClasspathEntry.is_internal_classpath_entry(cp_entry)]
 
+  def update(self, other):
+    """Adds the contents of other to this ClasspathProducts."""
+    if self._pants_workdir != other._pants_workdir:
+      raise ValueError('Other ClasspathProducts from a different pants workdir {}'.format(other._pants_workdir))
+    for target, products in other._classpaths._products_by_target.items():
+      self._classpaths.add_for_target(target, products)
+    for target, products in other._excludes._products_by_target.items():
+      self._excludes.add_for_target(target, products)
+
   def _filter_by_excludes(self, classpath_target_tuples, root_targets):
     # Excludes are always applied transitively, so regardless of whether a transitive
     # set of targets was included here, their closure must be included.

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

@@ -440,8 +440,7 @@ def execute(self):
       return
 
     # Clone the compile_classpath to the runtime_classpath.
-    compile_classpath = self.context.products.get_data('compile_classpath')
-    classpath_product = self.context.products.get_data('runtime_classpath', compile_classpath.copy)
+    classpath_product = self.create_runtime_classpath()
 
     def classpath_for_context(context):
       if self.get_options().use_classpath_jars:
@@ -484,6 +483,16 @@ def classpath_for_context(context):
             classpath_product.remove_for_target(cc.target, [(conf, cc.classes_dir)])
             classpath_product.add_for_target(cc.target, [(conf, cc.jar_file)])
 
+  def create_runtime_classpath(self):
+    compile_classpath = self.context.products.get_data('compile_classpath')
+    classpath_product = self.context.products.get_data('runtime_classpath')
+    if not classpath_product:
+      classpath_product = self.context.products.get_data('runtime_classpath', compile_classpath.copy)
+    else:
+      classpath_product.update(compile_classpath)
+
+    return classpath_product
+
   def do_compile(self,
                  invalidation_check,
                  compile_contexts,

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

@@ -13,6 +13,17 @@ python_tests(
   ],
 )
 
+python_tests(
+  name = 'jvm_compile',
+  sources = ['test_jvm_compile.py'],
+  dependencies = [
+    'src/python/pants/backend/jvm/tasks:classpath_products',
+    'src/python/pants/backend/jvm/tasks/jvm_compile',
+    'tests/python/pants_test/tasks:task_test_base',
+  ],
+)
+
+
 python_library(
   name='base_compile_integration_test',
   sources=['base_compile_integration_test.py'],

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

@@ -0,0 +1,49 @@
+# coding=utf-8
+# Copyright 2017 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)
+
+import os
+
+from pants.backend.jvm.targets.java_library import JavaLibrary
+from pants.backend.jvm.tasks.classpath_products import ClasspathProducts
+from pants.backend.jvm.tasks.jvm_compile.jvm_compile import JvmCompile
+from pants_test.tasks.task_test_base import TaskTestBase
+
+
+class DummyJvmCompile(JvmCompile):
+
+  def create_analysis_tools(self):
+    return None
+
+
+class JvmCompileTest(TaskTestBase):
+  DEFAULT_CONF = 'default'
+
+  @classmethod
+  def task_type(cls):
+    return DummyJvmCompile
+
+  def test_if_runtime_classpath_exists(self):
+    target = self.make_target(
+      'java/classpath:java_lib',
+      target_type=JavaLibrary,
+      sources=['com/foo/Bar.java'],
+    )
+
+    context = self.context(target_roots=[target])
+    compile_classpath = context.products.get_data('compile_classpath', ClasspathProducts.init_func(self.pants_workdir))
+
+    compile_entry = os.path.join(self.pants_workdir, 'compile-entry')
+    pre_init_runtime_entry = os.path.join(self.pants_workdir, 'pre-inited-runtime-entry')
+    compile_classpath.add_for_targets([target], [('default', compile_entry)])
+    runtime_classpath = context.products.get_data('runtime_classpath', ClasspathProducts.init_func(self.pants_workdir))
+
+    runtime_classpath.add_for_targets([target], [('default', pre_init_runtime_entry)])
+
+    task = self.create_task(context)
+    resulting_classpath = task.create_runtime_classpath()
+    self.assertEqual([('default', pre_init_runtime_entry), ('default', compile_entry)],
+      resulting_classpath.get_for_target(target))