Restore a gemfileparser module for compatibility

This is breaking downstream users like ScanCode otherwise

Reference: aboutcode-org/scancode-toolkit#3160
Reported-by: Daniel Thiele @danielthieleog
Signed-off-by: Philippe Ombredanne <pombredanne@nexb.com>

Author: pombredanne

MANIFEST.in

@@ -1,4 +1,4 @@
-graft gemfileparser2
+graft src
 graft tests
 
 include AUTHORS

setup.cfg

@@ -26,14 +26,23 @@ classifiers =
     Topic :: Utilities
 
 [options]
-zip_safe = False
-include_package_data = True
+package_dir =
+    =src
 packages = find:
+include_package_data = true
+zip_safe = false
+
+py_modules =
+    gemfileparser
+    gemfileparser2
+
 
 setup_requires = setuptools_scm[toml] >= 4
 
 python_requires = >=3.6.*
 
+[options.packages.find]
+where = src
 
 [options.extras_require]
 testing =

src/gemfileparser.py

@@ -0,0 +1,3 @@
+
+# compatibility import
+from gemfileparser2 import * # NOQA

gemfileparser2/__init__.py src/gemfileparser2.pygemfileparser2/__init__.py renamed to src/gemfileparser2.py

@@ -3,11 +3,8 @@
 # Copyright (c) Balasankar C <balasankarc@autistici.org> and others
 # SPDX-License-Identifier: GPL-3.0-or-later OR MIT
 
-import json
 import os
 
-from gemfileparser2 import GemfileParser
-
 TEST_DATA_DIR = os.path.join(os.path.dirname(__file__), 'data')
 
 
@@ -18,7 +15,16 @@ def check_gemparser_results(test_file, regen=False):
     "-expected.json" suffix appended.
     """
     test_file = os.path.join(TEST_DATA_DIR, test_file)
-    gemparser = GemfileParser(test_file)
+
+    from gemfileparser2 import GemfileParser as GemfileParser2
+    from gemfileparser import GemfileParser
+    _check_gemparser_results(test_file, parser=GemfileParser, regen=regen)
+    _check_gemparser_results(test_file, parser=GemfileParser2, regen=regen)
+
+
+def _check_gemparser_results(test_file, parser, regen=False):
+    import json
+    gemparser = parser(test_file)
     dependencies = {
         group: [dep.to_dict() for dep in deps]
         for group, deps in gemparser.parse().items()
@@ -72,7 +78,7 @@ def test_gemspec_3():
 
 
 def test_gemspec_no_deps():
-    check_gemparser_results("gemspecs/arel2.gemspec",  regen=False)
+    check_gemparser_results("gemspecs/arel2.gemspec", regen=False)
 
 
 def test_gemspec_4():