[ci] enforce flake8 (fixes #161)

.pre-commit-config.yaml

@@ -26,3 +26,7 @@ repos:
     hooks:
     -   id: isort
         args: ["--profile", "black", --line-length=100]
+-   repo: https://github.com/pycqa/flake8
+    rev: 5.0.4
+    hooks:
+    - id: flake8

hamilton/data_quality/default_validators.py

@@ -412,7 +412,7 @@ def arg(cls) -> str:
 def _append_pandera_to_default_validators():
     """Utility method to append pandera validators as needed"""
     try:
-        import pandera
+        import pandera  # noqa: F401
     except ModuleNotFoundError:
         logger.info(
             "Cannot import pandera from pandera_validators. Run pip install sf-hamilton[pandera] if needed."

hamilton/graph.py

@@ -110,7 +110,7 @@ def create_function_graph(
 
 def create_graphviz_graph(
     nodes: Set[node.Node], user_nodes: Set[node.Node], comment: str, graphviz_kwargs: dict
-) -> "graphviz.Digraph":
+) -> "graphviz.Digraph":  # noqa: F821
     """Helper function to create a graphviz graph.
 
     :param nodes: The set of computational nodes
@@ -136,7 +136,7 @@ def create_graphviz_graph(
 
 def create_networkx_graph(
     nodes: Set[node.Node], user_nodes: Set[node.Node], name: str
-) -> "networkx.DiGraph":
+) -> "networkx.DiGraph":  # noqa: F821
     """Helper function to create a networkx graph.
 
     :param nodes: The set of computational nodes
@@ -272,7 +272,7 @@ def display(
         """
         # Check to see if optional dependencies have been installed.
         try:
-            import graphviz
+            import graphviz  # noqa: F401
         except ModuleNotFoundError:
             logger.exception(
                 " graphviz is required for visualizing the function graph. Install it with:"

setup.cfg

@@ -0,0 +1,9 @@
+[flake8]
+max-line-length = 100
+exclude = build/,.git/
+ignore =
+    E203, # whitespace before ':' \
+    E402, # module level import not at top of file \
+    E501, # line too long \
+    W503, # line break before binary operator \
+    W605  # invalid escape sequence

tests/resources/bad_functions.py

@@ -2,7 +2,7 @@
 Module for more dummy functions to test graph things with.
 """
 # we import this to check we don't pull in this function when parsing this module.
-from tests.resources import only_import_me
+from tests.resources import only_import_me  # noqa: F401
 
 
 def A(b, c) -> int:

tests/resources/cyclic_functions.py

@@ -2,7 +2,7 @@
 Module for cyclic functions to test graph things with.
 """
 # we import this to check we don't pull in this function when parsing this module.
-from tests.resources import only_import_me
+from tests.resources import only_import_me  # noqa: F401
 
 
 def A(b: int, c: int) -> int: