Leverage default sources where possible.

Testing Done:
Used the following (on a modern linux distro) to ~autoconvert:
```
for t in java_library scala_library junit_tests python_library python_tests
do
  ./pants filter --type=$t :: \
  | cut -d: -f1 | sort -u | sed -e '/^$/d' -e 's|$|/BUILD|' \
  | while read f; do ls $f* || echo $f >2; done \
  | xargs sed -r -i "/\bsources\s*=\s*globs(['\"]*.[a-z]+['\"])\s*,?/d"
done
```

And then fixed up some failing tests by comparing the results of the
following when run on master and this branch - then fixing targets that
owned no files in the branch only:
```
./pants list {examples,testprojects}:: | {
  while read t; do
    [ -z "$(./pants filemap $t)" ] && echo "No files owned by $t"
  done
}
```

CI went green here:
  https://travis-ci.org/pantsbuild/pants/builds/173760812

Bugs closed: 4033

Reviewed at https://rbcommons.com/s/twitter/r/4358/

contrib/go/src/python/pants/contrib/go/subsystems/BUILD

@@ -2,7 +2,6 @@
 # Licensed under the Apache License, Version 2.0 (see LICENSE).
 
 python_library(
-  sources=globs('*.py'),
   dependencies=[
     '3rdparty/python:requests',
     '3rdparty/python:six',

contrib/python/src/python/pants/contrib/python/checks/tasks/BUILD

@@ -3,7 +3,6 @@
 
 python_library(
   name='python',
-  sources=globs('*.py'),
   resource_targets=[
     ':resources'
   ],

contrib/python/tests/python/pants_test/contrib/python/checks/tasks/checkstyle/BUILD

@@ -2,7 +2,6 @@
 # Licensed under the Apache License, Version 2.0 (see LICENSE).
 
 python_tests(
-  sources=globs('*.py'),
   dependencies=[
     'contrib/python/src/python/pants/contrib/python/checks/tasks/checkstyle:all',
     'src/python/pants/util:dirutil',

contrib/scalajs/src/python/pants/contrib/scalajs/subsystems/BUILD

@@ -8,5 +8,4 @@ python_library(
     'src/python/pants/subsystem',
     'src/python/pants/util:dirutil',
   ],
-  sources = globs('*.py'),
 )

contrib/scalajs/src/python/pants/contrib/scalajs/targets/BUILD

@@ -11,5 +11,4 @@ python_library(
     'src/python/pants/base:payload_field',
     'src/python/pants/build_graph',
   ],
-  sources = globs('*.py'),
 )

contrib/scalajs/src/python/pants/contrib/scalajs/tasks/BUILD

@@ -10,5 +10,4 @@ python_library(
     'src/python/pants/task',
     'src/python/pants/util:memo',
   ],
-  sources = globs('*.py'),
 )

contrib/scalajs/tests/scala/org/pantsbuild/scalajs/example/factfinder/BUILD

@@ -8,5 +8,4 @@ junit_tests(
     '3rdparty:scalatest',
     'contrib/scalajs/examples/src/scala/org/pantsbuild/scalajs/example/factfinder',
   ],
-  sources=globs('*.scala'),
 )

examples/src/java/org/pantsbuild/example/3rdparty_jvm.md

@@ -37,7 +37,7 @@ statements in your Java code.
 
 For example, your `BUILD` file might have
 
-!inc[start-after=sources&end-before=src/java](../../../../../tests/java/org/pantsbuild/example/hello/greet/BUILD)
+!inc[start-after=junit_tests&end-before=src/java](../../../../../tests/java/org/pantsbuild/example/hello/greet/BUILD)
 
 And your Java code might have:
 

examples/src/java/org/pantsbuild/example/java_sources/BUILD

@@ -2,7 +2,6 @@
 # Licensed under the Apache License, Version 2.0 (see LICENSE).
 
 java_library(
-  sources = globs('*.java'),
   dependencies = [
    'examples/src/scala/org/pantsbuild/example/scala_with_java_sources',
   ],

examples/src/python/example/README.md

@@ -137,9 +137,9 @@ Use `test` to run the tests. This uses `pytest`:
                          ============== test session starts ===============
                          platform darwin -- Python 2.6.8 -- py-1.4.20 -- pytest-2.5.2
                          plugins: cov, timeout
-                         collected 1 items
+                         collected 2 items
 
-                         examples/tests/python/example_test/hello/greet/greet.py .
+                         examples/tests/python/example_test/hello/greet/test_greet.py ..
 
                          ============ 1 passed in 0.02 seconds ============
 
@@ -310,7 +310,7 @@ parameters:
                          plugins: cov, timeout
                          collected 2 items
 
-                         examples/tests/python/example_test/hello/greet/greet.py .
+                         examples/tests/python/example_test/hello/greet/test_greet.py .
 
                          ========= 1 tests deselected by '-kreq' ==========
                          ===== 1 passed, 1 deselected in 0.05 seconds =====

examples/src/python/example/pants_publish_plugin/BUILD

@@ -3,7 +3,6 @@
 
 python_library(
   name='pants-publish-plugin',
-  sources=globs('*.py'),
   dependencies=[
     'src/python/pants/backend/jvm/targets:java',
     'src/python/pants/backend/jvm/tasks:jar_task',

examples/src/scala/org/pantsbuild/example/fact/BUILD

@@ -2,9 +2,7 @@
 # Licensed under the Apache License, Version 2.0 (see LICENSE).
 
 # A pure scala library, with no Java or 3rdparty dependencies.
-scala_library(
-  sources=globs('*.scala'),
-)
+scala_library()
 scala_js_library(name='fact-js',
   sources=globs('*.scala'),
 )

examples/src/scala/org/pantsbuild/example/hello/welcome/BUILD

@@ -7,7 +7,6 @@ scala_library(
   dependencies=[
     'examples/src/java/org/pantsbuild/example/hello/greet:greet',
   ],
-  sources=globs('*.scala'),
   resources = [
     'examples/src/resources/org/pantsbuild/example/hello',
   ],

examples/tests/java/org/pantsbuild/example/hello/greet/BUILD

@@ -4,7 +4,6 @@
 # Test the Hello World example's "greet" library
 
 junit_tests(
-  sources=globs('*.java'),
   dependencies=[
     'examples/src/java/org/pantsbuild/example/hello/greet',
   ],

examples/tests/python/example_test/hello/greet/BUILD

@@ -8,7 +8,6 @@ python_tests(
     'examples/src/python/example/hello/greet:greet',
     ':prep',
   ],
-  sources=globs('*.py'),
 )
 
 # Prepare for the 'greet' test. Realistically, you wouldn't set up a

examples/tests/scala/org/pantsbuild/example/hello/welcome/BUILD

@@ -7,5 +7,4 @@ junit_tests(
     '3rdparty:junit',
     '3rdparty:scalatest',
   ],
-  sources=globs('*.scala'),
 )

pants-plugins/tests/python/internal_backend_test/utilities/BUILD

@@ -2,7 +2,6 @@
 # Licensed under the Apache License, Version 2.0 (see LICENSE).
 
 python_tests(
-  sources=globs('*.py'),
   dependencies=[
     'pants-plugins/src/python/internal_backend/utilities:plugin',
     'src/python/pants/base:revision',

src/java/com/sun/tools/javac/api/BUILD

@@ -3,7 +3,6 @@
 
 
 java_library(
-  sources=globs('*.java'),
   dependencies=[
   ],
   platform='java7',

src/java/org/pantsbuild/args4j/BUILD

@@ -2,7 +2,6 @@
 # Licensed under the Apache License, Version 2.0 (see LICENSE).
 
 java_library(
-  sources=globs('*.java'),
   dependencies=[
     '3rdparty:args4j',
     '3rdparty:guava',

src/java/org/pantsbuild/junit/annotations/BUILD

@@ -10,6 +10,5 @@ java_library(
       Annotations for use with org.pantsbuild#junit-runner that support running tests in parallel.
     """)
   ),
-  sources=globs('*.java'),
   platform='java7',
 )

src/java/org/pantsbuild/testing/BUILD

@@ -2,6 +2,7 @@
 # Licensed under the Apache License, Version 2.0 (see LICENSE).
 
 java_library(
+  # We have to use explicit sources here to grab `EasyMockTest.java` which otherwise gets excluded.
   sources=globs('*.java'),
   dependencies=[
     '3rdparty:easymock',

src/java/org/pantsbuild/tools/jar/BUILD

@@ -2,7 +2,6 @@
 # Licensed under the Apache License, Version 2.0 (see LICENSE).
 
 java_library(
-  sources=globs('*.java'),
   dependencies=[
     '3rdparty:args4j',
     '3rdparty:guava',

src/java/org/pantsbuild/tools/junit/withretry/BUILD

@@ -13,6 +13,5 @@ java_library(
   dependencies=[
     '3rdparty:junit',
   ],
-  sources=globs('*.java'),
   platform='java7',
 )

src/java/org/pantsbuild/tools/runner/BUILD

@@ -14,7 +14,6 @@ java_library(
   dependencies=[
     '3rdparty:guava',
   ],
-  sources=globs('*.java'),
   platform='java7',
 )
 

src/python/pants/backend/docgen/targets/BUILD

@@ -3,7 +3,6 @@
 
 
 python_library(
-  sources = globs('*.py'),
   dependencies = [
     'src/python/pants/base:payload',
     'src/python/pants/base:payload_field',

src/python/pants/backend/docgen/tasks/BUILD

@@ -2,7 +2,6 @@
 # Licensed under the Apache License, Version 2.0 (see LICENSE).
 
 python_library(
-  sources = globs('*.py'),
   resource_targets = [
     ':resources',
   ],

src/python/pants/backend/graph_info/tasks/BUILD

@@ -2,7 +2,6 @@
 # Licensed under the Apache License, Version 2.0 (see LICENSE).
 
 python_library(
-  sources = globs('*.py'),
   dependencies = [
     'src/python/pants/base:build_environment',
     'src/python/pants/base:cmd_line_spec_parser',

src/python/pants/backend/jvm/zinc/BUILD

@@ -1,5 +1,4 @@
 python_library(
-  sources = globs('*.py'),
   dependencies = [
     '3rdparty/python:six',
   ],

src/python/pants/backend/python/tasks/BUILD

@@ -3,7 +3,6 @@
 
 python_library(
   name='python',
-  sources=globs('*.py'),
   dependencies=[
     '3rdparty/python/twitter/commons:twitter.common.collections',
     '3rdparty/python/twitter/commons:twitter.common.dirutil',

src/python/pants/build_graph/BUILD

@@ -3,7 +3,6 @@
 
 
 python_library(
-  sources = globs('*.py'),
   dependencies = [
     '3rdparty/python/twitter/commons:twitter.common.collections',
     '3rdparty/python:six',

src/python/pants/cache/BUILD

@@ -2,7 +2,6 @@
 # Licensed under the Apache License, Version 2.0 (see LICENSE).
 
 python_library(
-  sources = globs('*.py'),
   dependencies = [
     '3rdparty/python:requests',
     '3rdparty/python:six',

src/python/pants/core_tasks/BUILD

@@ -2,7 +2,6 @@
 # Licensed under the Apache License, Version 2.0 (see LICENSE).
 
 python_library(
-  sources=globs('*.py'),
   resource_targets=[':templates',],
   dependencies=[
     '3rdparty/python:ansicolors',

src/python/pants/fs/BUILD

@@ -2,7 +2,6 @@
 # Licensed under the Apache License, Version 2.0 (see LICENSE).
 
 python_library(
-  sources = globs('*.py'),
   dependencies = [
     'src/python/pants/util:contextutil',
     'src/python/pants/util:meta',

src/python/pants/help/BUILD

@@ -2,7 +2,6 @@
 # Licensed under the Apache License, Version 2.0 (see LICENSE).
 
 python_library(
-  sources=globs('*.py'),
   dependencies=[
     'src/python/pants/base:build_environment',
     'src/python/pants/base:exceptions',

src/python/pants/invalidation/BUILD

@@ -3,7 +3,6 @@
 
 
 python_library(
-  sources = globs('*.py'),
   dependencies = [
     'src/python/pants/base:hash_utils',
     'src/python/pants/build_graph',

src/python/pants/ivy/BUILD

@@ -2,7 +2,6 @@
 # Licensed under the Apache License, Version 2.0 (see LICENSE).
 
 python_library(
-  sources = globs('*.py'),
   dependencies = [
     '3rdparty/python/twitter/commons:twitter.common.collections',
     '3rdparty/python:six',

src/python/pants/java/junit/BUILD

@@ -2,7 +2,6 @@
 # Licensed under the Apache License, Version 2.0 (see LICENSE).
 
 python_library(
-  sources=globs('*.py'),
   dependencies=[
     '3rdparty/python/twitter/commons:twitter.common.collections',
     'src/python/pants/util:objects',

src/python/pants/logging/BUILD

@@ -2,7 +2,6 @@
 # Licensed under the Apache License, Version 2.0 (see LICENSE).
 
 python_library(
-  sources=globs('*.py'),
   dependencies=[
     'src/python/pants/util:dirutil',
   ],

src/python/pants/option/BUILD

@@ -2,7 +2,6 @@
 # Licensed under the Apache License, Version 2.0 (see LICENSE).
 
 python_library(
-  sources=globs('*.py'),
   dependencies=[
     '3rdparty/python:ansicolors',
     '3rdparty/python:six',

src/python/pants/process/BUILD

@@ -2,7 +2,6 @@
 # Licensed under the Apache License, Version 2.0 (see LICENSE).
 
 python_library(
-  sources = globs('*.py'),
   dependencies = [
     '3rdparty/python:fasteners',
     '3rdparty/python:psutil',

src/python/pants/source/BUILD

@@ -2,7 +2,6 @@
 # Licensed under the Apache License, Version 2.0 (see LICENSE).
 
 python_library(
-  sources=globs('*.py'),
   dependencies=[
     '3rdparty/python:six',
     '3rdparty/python/twitter/commons:twitter.common.dirutil',

src/python/pants/stats/BUILD

@@ -2,7 +2,6 @@
 # Licensed under the Apache License, Version 2.0 (see LICENSE).
 
 python_library(
-  sources = globs('*.py'),
   dependencies = [
     'src/python/pants/subsystem',
     'src/python/pants/util:dirutil',

src/python/pants/subsystem/BUILD

@@ -2,7 +2,6 @@
 # Licensed under the Apache License, Version 2.0 (see LICENSE).
 
 python_library(
-  sources = globs('*.py'),
   dependencies = [
     '3rdparty/python/twitter/commons:twitter.common.collections',
     'src/python/pants/option'

src/python/pants/task/BUILD

@@ -3,7 +3,6 @@
 
 
 python_library(
-  sources = globs('*.py'),
   dependencies = [
     'src/python/pants/base:build_environment',
     'src/python/pants/base:exceptions',

src/scala/org/pantsbuild/zinc/BUILD

@@ -13,7 +13,6 @@ scala_library(
     'src/scala/sbt/compiler/javac',
     'src/scala/sbt/inc',
   ],
-  sources=globs('*.scala'),
   strict_deps=True,
   platform='java7',
 )

src/scala/org/pantsbuild/zinc/cache/BUILD

@@ -9,7 +9,6 @@ scala_library(
     '3rdparty:guava',
     '3rdparty:jsr305',
   ],
-  sources=globs('*.scala'),
   strict_deps=True,
   platform='java7',
 )

src/scala/org/pantsbuild/zinc/logging/BUILD

@@ -8,7 +8,6 @@ scala_library(
   dependencies=[
     '3rdparty/jvm/com/typesafe/sbt:incremental-compiler',
   ],
-  sources=globs('*.scala'),
   strict_deps=True,
   platform='java7',
 )

src/scala/sbt/compiler/javac/BUILD

@@ -8,6 +8,5 @@ scala_library(
   dependencies=[
     '3rdparty/jvm/com/typesafe/sbt:incremental-compiler',
   ],
-  sources=globs('*.scala'),
   platform='java7',
 )

src/scala/sbt/inc/BUILD

@@ -8,6 +8,5 @@ scala_library(
   dependencies=[
     '3rdparty/jvm/com/typesafe/sbt:incremental-compiler',
   ],
-  sources=globs('*.scala'),
   platform='java7',
 )

testprojects/src/java/org/pantsbuild/testproject/annotation/processorwithdep/hellomaker/BUILD

@@ -2,6 +2,5 @@
 # Licensed under the Apache License, Version 2.0 (see LICENSE).
 
 java_library(
-  sources = globs('*.java'),
   dependencies = [],
 )