Cleanup v1 changed code. (#5572)

This marks off some TODO's around non-deprecation-bound 1.5.0 removals and seals the v2 engine variant components into pants.scm from pants.engine.

src/python/pants/bin/BUILD

@@ -17,9 +17,9 @@ python_library(
     'src/python/pants/build_graph',
     'src/python/pants/core_tasks',
     'src/python/pants/engine/legacy:address_mapper',
-    'src/python/pants/engine/legacy:change_calculator',
     'src/python/pants/engine/legacy:graph',
     'src/python/pants/engine/legacy:parser',
+    'src/python/pants/engine/legacy:source_mapper',
     'src/python/pants/engine:build_files',
     'src/python/pants/engine:fs',
     'src/python/pants/engine:legacy_engine',
@@ -35,6 +35,7 @@ python_library(
     'src/python/pants/option',
     'src/python/pants/reporting',
     'src/python/pants/pantsd:pants_daemon',
+    'src/python/pants/scm:change_calculator',
     'src/python/pants/scm/subsystems:changed',
     'src/python/pants/subsystem',
     'src/python/pants/task',

src/python/pants/bin/engine_initializer.py

@@ -14,7 +14,6 @@
 from pants.engine.fs import create_fs_rules
 from pants.engine.isolated_process import create_process_rules
 from pants.engine.legacy.address_mapper import LegacyAddressMapper
-from pants.engine.legacy.change_calculator import EngineChangeCalculator
 from pants.engine.legacy.graph import HydratedTargets, LegacyBuildGraph, create_legacy_graph_tasks
 from pants.engine.legacy.parser import LegacyPythonCallbacksParser
 from pants.engine.legacy.structs import (GoTargetAdaptor, JavaLibraryAdaptor, JunitTestsAdaptor,
@@ -27,6 +26,7 @@
 from pants.engine.scheduler import LocalScheduler
 from pants.init.options_initializer import OptionsInitializer
 from pants.option.options_bootstrapper import OptionsBootstrapper
+from pants.scm.change_calculator import EngineChangeCalculator
 
 
 logger = logging.getLogger(__name__)

src/python/pants/bin/goal_runner.py

@@ -220,7 +220,7 @@ def subsystems(cls):
       Reporting,
       Reproducer,
       RunTracker,
-      Changed.Factory,
+      Changed,
       BinaryUtil.Factory,
       Subprocess.Factory
     }

src/python/pants/build_graph/source_mapper.py

@@ -18,6 +18,8 @@ def target_addresses_for_source(self, source):
     raise NotImplementedError
 
 
+# TODO: Kill this in favor of `EngineSourceMapper` once pants/backend/graph_info/tasks/list_owners.py
+# (which consumes LazySourceMapper) is ported to the v2 engine.
 class SpecSourceMapper(SourceMapper):
   """
   Uses sources specs to identify an owner target of a source.

src/python/pants/engine/legacy/BUILD

@@ -80,13 +80,3 @@ python_library(
     '3rdparty/python:six'
   ]
 )
-
-python_library(
-  name='change_calculator',
-  sources=['change_calculator.py'],
-  dependencies=[
-    'src/python/pants/engine/legacy:source_mapper',
-    'src/python/pants/goal:workspace',
-    'src/python/pants/scm:change_calculator',
-  ]
-)

src/python/pants/init/BUILD

@@ -15,7 +15,6 @@ python_library(
     'src/python/pants/build_graph',
     'src/python/pants/core_tasks',
     'src/python/pants/engine:native',
-    'src/python/pants/engine/legacy:change_calculator',
     'src/python/pants/goal',
     'src/python/pants/goal:run_tracker',
     'src/python/pants/logging',

src/python/pants/init/target_roots.py

@@ -44,7 +44,6 @@ def create(cls, options, build_root=None, change_calculator=None):
     :param string build_root: The build root.
     :param ChangeCalculator change_calculator: A `ChangeCalculator` for calculating changes.
     """
-
     # Determine the literal target roots.
     spec_roots = cls.parse_specs(options.target_specs, build_root)
 
@@ -53,7 +52,6 @@ def create(cls, options, build_root=None, change_calculator=None):
     changed_options = options.for_scope('changed')
     changed_request = ChangedRequest.from_options(changed_options)
 
-
     logger.debug('spec_roots are: %s', spec_roots)
     logger.debug('changed_request is: %s', changed_request)