Exclude Antlr test from testprojects to avoid interpreter conflict (#…

…6944)

### Problem
Antlr 3 only works with Python 2, so we have to constrain that part to only using Python 2, as done in #6924.

However, this results in one of the `testprojects` shards failing when using Python 3 due to mixing a Py2-only constraint with a Py3-only constraint.

```bash
$ export PANTS_PYTHON_SETUP_INTERPRETER_CONSTRAINTS='["CPython>=3.5,<4"]'
$ ./pants clean-all test testprojects/src/python/antlr:eval testprojects/src/python/antlr:eval-bin testprojects/src/python/coordinated_runs:creator testprojects/src/python/coordinated_runs:phaser testprojects/src/python/coordinated_runs:waiter testprojects/src/python/print_env:print_env

...

18:47:02 00:04   [pyprep]
18:47:02 00:04     [interpreter]
                   Invalidated 4 targets.
FAILURE: Unable to detect a suitable interpreter for compatibilities: CPython>=2.7,<3 && CPython>=3.5,<4 (Conflicting targets: testprojects/src/python/antlr:eval, testprojects/src/python/coordinated_runs:creator)
```

We can get Antlr to evaluate correctly when there are no other targets, but `test_testprojects_integration.py` works by running multiple targets with one single command so this does not help.

```bash
$ export PANTS_PYTHON_SETUP_INTERPRETER_CONSTRAINTS='["CPython>=3.5,<4"]'
$ ./pants clean-all test testprojects/src/python/antlr:eval testprojects/src/python/antlr:eval-bin 

{interpreter will resolve correctly}
```

### Solution
Exclude the Antlr testproject from `projects/testprojects`. The code is already covered by the tests in `backend/codegen/antlr/test_antlr_py_gen_integration.py`.

This is a much simpler solution than trying to come up with logic in `test_testprojects_integration.py` to handle interpreter conflicts like this, e.g. putting Python 2 only targets in one dedicated shard.

### Also fixes duplicate .so binary names
By removing the antlr test, the shards were redistributed in `test_testprojects_integration.py`. This led to `python_distribution/ctypes` and `python_distribution/ctypes_with_extra_compiler_flags` running at the same time, which resulted in the error `FAILURE: The name 'asdf-cpp' was used for two shared libraries`.

We fix this by making the `asdf-cpp` name unique for all of the 3 uses.

testprojects/src/python/python_distribution/ctypes/BUILD

@@ -4,13 +4,13 @@
 ctypes_compatible_c_library(
   name='c_library',
   sources=['some_math.h', 'some_math.c', 'src-subdir/add_three.h', 'src-subdir/add_three.c'],
-  ctypes_native_library=native_artifact(lib_name='asdf-c'),
+  ctypes_native_library=native_artifact(lib_name='asdf-c_ctypes'),
 )
 
 ctypes_compatible_cpp_library(
   name='cpp_library',
   sources=['some_more_math.hpp', 'some_more_math.cpp'],
-  ctypes_native_library=native_artifact(lib_name='asdf-cpp'),
+  ctypes_native_library=native_artifact(lib_name='asdf-cpp_ctypes'),
 )
 
 python_dist(

testprojects/src/python/python_distribution/ctypes/ctypes_python_pkg/ctypes_wrapper.py

@@ -16,8 +16,8 @@ def get_generated_shared_lib(lib_name):
   return os.path.normpath(rel_path)
 
 
-asdf_c_lib_path = get_generated_shared_lib('asdf-c')
-asdf_cpp_lib_path = get_generated_shared_lib('asdf-cpp')
+asdf_c_lib_path = get_generated_shared_lib('asdf-c_ctypes')
+asdf_cpp_lib_path = get_generated_shared_lib('asdf-cpp_ctypes')
 
 asdf_c_lib = ctypes.CDLL(asdf_c_lib_path)
 asdf_cpp_lib = ctypes.CDLL(asdf_cpp_lib_path)

testprojects/src/python/python_distribution/ctypes/setup.py

@@ -12,5 +12,5 @@
   version='0.0.1',
   packages=find_packages(),
   # Declare two files at the top-level directory (denoted by '').
-  data_files=[('', ['libasdf-c.so', 'libasdf-cpp.so'])],
+  data_files=[('', ['libasdf-c_ctypes.so', 'libasdf-cpp_ctypes.so'])],
 )

testprojects/src/python/python_distribution/ctypes_with_extra_compiler_flags/BUILD

@@ -4,7 +4,7 @@
 ctypes_compatible_cpp_library(
   name='cpp_library',
   sources=['some_more_math.hpp', 'some_more_math.cpp'],
-  ctypes_native_library=native_artifact(lib_name='asdf-cpp'),
+  ctypes_native_library=native_artifact(lib_name='asdf-cpp_ctypes-with-extra-compiler-flags'),
   compiler_option_sets={'asdf'},
 )
 

testprojects/src/python/python_distribution/ctypes_with_extra_compiler_flags/ctypes_python_pkg/ctypes_wrapper.py

@@ -16,7 +16,7 @@ def get_generated_shared_lib(lib_name):
   return os.path.normpath(rel_path)
 
 
-asdf_cpp_lib_path = get_generated_shared_lib('asdf-cpp')
+asdf_cpp_lib_path = get_generated_shared_lib('asdf-cpp_ctypes-with-extra-compiler-flags')
 asdf_cpp_lib = ctypes.CDLL(asdf_cpp_lib_path)
 
 def f(x):

testprojects/src/python/python_distribution/ctypes_with_extra_compiler_flags/setup.py

@@ -11,5 +11,5 @@
   name='ctypes_test',
   version='0.0.1',
   packages=find_packages(),
-  data_files=[('', ['libasdf-cpp.so'])],
+  data_files=[('', ['libasdf-cpp_ctypes-with-extra-compiler-flags.so'])],
 )

testprojects/src/python/python_distribution/ctypes_with_third_party/BUILD

@@ -6,7 +6,7 @@
 ctypes_compatible_cpp_library(
   name='cpp_library_with_third_party',
   sources=['some_more_math.hpp', 'some_more_math_with_third_party.cpp'],
-  ctypes_native_library=native_artifact(lib_name='asdf-cpp-tp'),
+  ctypes_native_library=native_artifact(lib_name='asdf-cpp_ctypes-with-third-party'),
   dependencies=[':rang', ':cereal'],
   fatal_warnings=False
 )

testprojects/src/python/python_distribution/ctypes_with_third_party/ctypes_python_pkg/ctypes_wrapper.py

@@ -16,7 +16,7 @@ def get_generated_shared_lib(lib_name):
   return os.path.normpath(rel_path)
 
 
-asdf_cpp_lib_path = get_generated_shared_lib('asdf-cpp-tp')
+asdf_cpp_lib_path = get_generated_shared_lib('asdf-cpp_ctypes-with-third-party')
 asdf_cpp_lib = ctypes.CDLL(asdf_cpp_lib_path)
 
 def f(x):

testprojects/src/python/python_distribution/ctypes_with_third_party/setup.py

@@ -12,5 +12,5 @@
   version='0.0.1',
   packages=find_packages(),
   # Declare one shared lib at the top-level directory (denoted by '').
-  data_files=[('', ['libasdf-cpp-tp.so'])],
+  data_files=[('', ['libasdf-cpp_ctypes-with-third-party.so'])],
 )

tests/python/pants_test/backend/python/tasks/test_ctypes_integration.py

@@ -108,7 +108,7 @@ def _assert_ctypes_binary_creation(self, toolchain_variant):
       wheel_files = ZipFile(wheel_dist_with_path).namelist()
 
       dist_versioned_name = '{}-{}.data'.format(dist_name, dist_version)
-      for shared_lib_filename in ['libasdf-c.so', 'libasdf-cpp.so']:
+      for shared_lib_filename in ['libasdf-c_ctypes.so', 'libasdf-cpp_ctypes.so']:
         full_path_in_wheel = os.path.join(dist_versioned_name, 'data', shared_lib_filename)
         self.assertIn(full_path_in_wheel, wheel_files)
 

tests/python/pants_test/projects/test_testprojects_integration.py

@@ -80,6 +80,12 @@ def targets(self):
       'examples/src/java/org/pantsbuild/example/plugin',
     ]
 
+    # Interpreter will not resolve correctly when Pants is constrained to Python 3
+    python2_only = [
+      # tested in test_antlr_py_gen_integration.py
+      'testprojects/src/python/antlr'
+    ]
+
     # Targets for testing timeouts. These should only be run during specific integration tests,
     # because they take a long time to run.
     timeout_targets = [
@@ -104,7 +110,7 @@ def targets(self):
       'testprojects/src/python/python_distribution/ctypes_with_extra_compiler_flags:bin',
     ]
 
-    targets_to_exclude = (known_failing_targets + negative_test_targets + need_java_8 +
+    targets_to_exclude = (known_failing_targets + negative_test_targets + need_java_8 + python2_only +
                           timeout_targets + deliberately_conflicting_targets + simply_skip)
     exclude_opts = ['--exclude-target-regexp={}'.format(target) for target in targets_to_exclude]