Fixes the bug where pants doesn't recognize build targets on top-leve…

…l directories.

The previous argument parser naively simply checked whether a command-line argument contained a slash (/) or a colon (:). This is a reasonable assumption most of the time, but in the case where a BUILD file is located only one directory deep, (eg, buildroot/folder/BUILD), this makes it impossible to run pants on the target simply by calling (eg) ./pants goal bundle folder.

See github issue for example: pantsbuild#159

This fixes it by actually checking to see if a phase with goals is defined by the command-line argument. It still checks before that whether the argument contains a slash or a colon, because that if an argument has those characters it can't mean a goal. But an argument not having those characters doesn't mean it is a goal.

In a completely ambiguous situation (eg, given a command argument 'bundle', and there is a valid BUILD file at bundle/BUILD), we err on the side of the goal, and print out a warning. This makes sense, because it allows the user to disambiguate the situation using the '--' syntax.

src/python/pants/commands/goal.py

@@ -6,6 +6,7 @@
 
 from contextlib import contextmanager
 import inspect
+import logging
 import os
 import sys
 import traceback
@@ -18,6 +19,7 @@
 
 from pants.backend.core.tasks.console_task import ConsoleTask
 from pants.backend.core.tasks.task import Task
+from pants.backend.jvm.tasks.nailgun_task import NailgunTask  # XXX(pl)
 from pants.base.address import BuildFileAddress, parse_spec
 from pants.base.build_environment import get_buildroot
 from pants.base.build_file import BuildFile
@@ -34,7 +36,6 @@
 from pants.goal.help import print_help
 from pants.goal.initialize_reporting import update_reporting
 from pants.goal.option_helpers import add_global_options
-from pants.backend.jvm.tasks.nailgun_task import NailgunTask  # XXX(pl)
 
 
 StringIO = Compatibility.StringIO
@@ -51,9 +52,34 @@ def parse_args(args):
     goals = OrderedSet()
     specs = OrderedSet()
     explicit_multi = False
+    logger = logging.getLogger(__name__)
+    double_dash = u'--' in args
+    goal_names = [phase.name for phase, goal in Phase.all()]
+    if not goal_names:
+      raise RuntimeError(
+        'Arguments cannot be parsed before the list of goals from Phase.all() is populated.')
 
     def is_spec(spec):
-      return os.sep in spec or ':' in spec
+      if os.sep in spec or ':' in spec:
+        return True # Definitely not a goal.
+      if not (spec in goal_names):
+        return True # Definitely not a (known) goal.
+      if double_dash:
+        # This means that we're parsing the half of the expression before a --, so assume it's a
+        # goal without warning.
+        return False
+      # Here, it's possible we have a goal and target with the same name. For now, always give
+      # priority to the goal, but give a warning if they might have meant the target (if the BUILD
+      # file exists).
+      try:
+        BuildFile(get_buildroot(), spec)
+        msg = (' Command-line argument "{spec}" is ambiguous, and was assumed to be a goal.'
+               ' If this is incorrect, disambiguate it with the "--" argument to separate goals'
+               ' from targets.')
+        logger.warning(msg.format(spec=spec))
+      except IOError: pass # Awesome, it's unambiguous.
+      return False
+
 
     for i, arg in enumerate(args):
       if not arg.startswith('-'):

tests/BUILD

@@ -0,0 +1,12 @@
+# Copyright 2014 Pants project contributors (see CONTRIBUTORS.md).
+# Licensed under the Apache License, Version 2.0 (see LICENSE).
+
+# Yes, this is a weird place for this BUILD file. It's here to test if pants can handle targets that
+# are only 1 directory deep, and thus might not have a ':' or '/' on the spec path. (which goal.py
+# previously has been bad about.)
+java_library(name='tests',
+  sources=[],
+  dependencies=[
+    'tests/java/com/pants/examples/hello/greet',
+  ],
+)

tests/python/pants_test/commands/BUILD

@@ -20,6 +20,7 @@ python_tests(
   name = 'test_goal',
   sources = [ 'test_goal.py' ],
   dependencies = [
+    pants('src/python/pants/backend/jvm:plugin'),
     pants('src/python/pants/commands:goal'),
     pants('tests/python/pants_test:base_test'),
   ]

tests/python/pants_test/commands/test_goal.py

@@ -6,11 +6,17 @@
 
 import unittest
 
+from pants.backend.jvm.register import register_goals
 from pants.commands.goal import Goal, GoalError
 
 
 class GoalTest(unittest.TestCase):
   def test_parse_args(self):
+    # Have to load in goals, because parse_args requires Phase.all() now.
+    # Fortunately, we only have to load in the goals we're actually using below, so the goals in the
+    # core register are sufficient.
+    register_goals()
+
     def assert_result(goals, specs, args):
       g, s = Goal.parse_args(args)
       self.assertEquals((goals, specs), (list(g), list(s)))