Lint the code.

Additionally move the code to a src directory so meta/config can be
used later on.

.travis.yml

@@ -10,6 +10,11 @@ python:
     - 3.8
     - pypy2
     - pypy3
+matrix:
+  include:
+    - name: "lint"
+      python: 3.7
+      env: TOXENV="lint"
 
 install:
     - pip install zope.testrunner coverage coveralls

setup.py

@@ -56,7 +56,8 @@ def _read_file(filename):
       url="https://github.com/zopefoundation/transaction",
       license="ZPL 2.1",
       platforms=["any"],
-      packages=find_packages(),
+      packages=find_packages('src'),
+      package_dir={'': 'src'},
       include_package_data=True,
       zip_safe=False,
       test_suite="transaction.tests",

transaction/__init__.py → src/transaction/__init__.py

@@ -16,11 +16,11 @@
 """
 
 #: Default implementation of `~ITransaction`
-from transaction._transaction import Transaction
+from transaction._transaction import Transaction  # noqa: F401 unused import
 #: Default implementation of `~ISavepoint`
-from transaction._transaction import Savepoint
+from transaction._transaction import Savepoint  # noqa: F401 unused import
 #: A single-threaded `~ITransactionManager`
-from transaction._manager import TransactionManager
+from transaction._manager import TransactionManager  # noqa: F401 unused import
 #: A thread-safe `~ITransactionManager`
 from transaction._manager import ThreadTransactionManager
 
@@ -29,8 +29,8 @@
 # via getattr and getattribute; see http://bugs.python.org/issue12022.  On
 # Python 3, you must use ``with transaction.manager`` instead.
 
-#: The default transaction manager (a `~.ThreadTransactionManager`). All other functions in
-#: this module refer to this object.
+#: The default transaction manager (a `~.ThreadTransactionManager`). All other
+#: functions in this module refer to this object.
 manager = ThreadTransactionManager()
 #: See `.ITransactionManager.get`
 get = __enter__ = manager.get

transaction/_compat.py → src/transaction/_compat.py

@@ -6,15 +6,17 @@
 
 if PY3:  # pragma: no cover
     text_type = str
-else: # pragma: no cover
+else:  # pragma: no cover
     # py2
-    text_type = unicode
+    text_type = unicode  # noqa: F821 undefined name 'unicode'
+
 
 def text_(s):
     if not isinstance(s, text_type):  # pragma: no cover
         s = s.decode('utf-8')
     return s
 
+
 if PY3:  # pragma: no cover
     def native_(s, encoding='latin-1', errors='strict'):
         if isinstance(s, text_type):
@@ -28,10 +30,12 @@ def native_(s, encoding='latin-1', errors='strict'):
 
 if PY3:  # pragma: no cover
     from io import StringIO
-else: # pragma: no cover
+else:  # pragma: no cover
     from io import BytesIO
     # Prevent crashes in IPython when writing tracebacks if a commit fails
-    # ref: https://github.com/ipython/ipython/issues/9126#issuecomment-174966638
+    # ref:
+    # https://github.com/ipython/ipython/issues/9126#issuecomment-174966638
+
     class StringIO(BytesIO):
         def write(self, s):
             s = native_(s, encoding='utf-8')
@@ -40,11 +44,11 @@ def write(self, s):
 
 if PY3:  # pragma: no cover
     def reraise(tp, value, tb=None):
-        if value.__traceback__ is not tb: # pragma: no cover
+        if value.__traceback__ is not tb:  # pragma: no cover
             raise value.with_traceback(tb)
         raise value
 
-else: # pragma: no cover
+else:  # pragma: no cover
     def exec_(code, globs=None, locs=None):
         """Execute code in a namespace."""
         if globs is None:
@@ -64,6 +68,6 @@ def exec_(code, globs=None, locs=None):
 
 try:  # pragma: no cover
     from threading import get_ident as get_thread_ident
-except ImportError: # pragma: no cover
-    # py2
-    from thread import get_ident as get_thread_ident
+except ImportError:  # pragma: no cover
+    # PY2
+    from thread import get_ident as get_thread_ident  # noqa: F401 unused

transaction/_manager.py → src/transaction/_manager.py

@@ -61,8 +61,8 @@ def _new_transaction(txn, synchs):
 
 @implementer(ITransactionManager)
 class TransactionManager(object):
-    """
-    Single-thread implementation of `~transaction.interfaces.ITransactionManager`.
+    """Single-thread implementation of
+    `~transaction.interfaces.ITransactionManager`.
     """
 
     def __init__(self, explicit=False):
@@ -71,8 +71,7 @@ def __init__(self, explicit=False):
         self._synchs = WeakSet()
 
     def begin(self):
-        """ See `~transaction.interfaces.ITransactionManager`.
-        """
+        """See `~transaction.interfaces.ITransactionManager`."""
         if self._txn is not None:
             if self.explicit:
                 raise AlreadyInTransaction()
@@ -81,11 +80,11 @@ def begin(self):
         _new_transaction(txn, self._synchs)
         return txn
 
-    __enter__ = lambda self: self.begin()
+    def __enter__(self):
+        self.begin()
 
     def get(self):
-        """ See `~transaction.interfaces.ITransactionManager`.
-        """
+        """See `~transaction.interfaces.ITransactionManager`."""
         if self._txn is None:
             if self.explicit:
                 raise NoTransaction()
@@ -174,6 +173,7 @@ def _retryable(self, error_type, error):
         return False
 
     run_no_func_types = int, type(None)
+
     def run(self, func=None, tries=3):
         if isinstance(func, self.run_no_func_types):
             if func is not None:
@@ -222,8 +222,8 @@ def run(self, func=None, tries=3):
 
 @implementer(ITransactionManager)
 class ThreadTransactionManager(threading.local):
-    """
-    Thread-local `transaction manager <transaction.interfaces.ITransactionManager>`.
+    """Thread-local
+    `transaction manager <transaction.interfaces.ITransactionManager>`.
 
     A thread-local transaction manager can be used as a global
     variable, but has a separate copy for each thread.
@@ -289,6 +289,7 @@ def attempts(self, number=3):
     def run(self, func=None, tries=3):
         return self.manager.run(func, tries)
 
+
 class Attempt(object):
 
     success = False
@@ -300,8 +301,8 @@ def _retry_or_raise(self, t, v, tb):
         retry = self.manager._retryable(t, v)
         self.manager.abort()
         if retry:
-            return retry # suppress the exception if necessary
-        reraise(t, v, tb) # otherwise reraise the exception
+            return retry  # suppress the exception if necessary
+        reraise(t, v, tb)  # otherwise reraise the exception
 
     def __enter__(self):
         return self.manager.__enter__()
@@ -310,7 +311,7 @@ def __exit__(self, t, v, tb):
         if v is None:
             try:
                 self.manager.commit()
-            except:
+            except:  # noqa: E722 do not use bare 'except'
                 return self._retry_or_raise(*sys.exc_info())
             else:
                 self.success = True