feat(poly check): exclude imports within "if TYPE_CHECKING" (#406)

* feat: parse module imports, and exclude imports within an if TYPE_CHECKING clause

* bump Polylith plugin to 1.46.0

* bump CLI to 1.40.0

Author: DavidVujic

components/polylith/imports/parser.py

@@ -2,7 +2,10 @@
 from collections.abc import Iterable
 from functools import lru_cache
 from pathlib import Path
-from typing import List, Set
+from typing import List, Set, Union
+
+typing_ns = "typing"
+type_checking = "TYPE_CHECKING"
 
 
 def parse_import(node: ast.Import) -> List[str]:
@@ -31,6 +34,40 @@ def parse_imports(node: ast.AST) -> List[str]:
     return []
 
 
+def find_type_checking_body(node: ast.If) -> List[ast.stmt]:
+    if isinstance(node.test, ast.Name) and node.test.id == type_checking:
+        return node.body
+
+    if isinstance(node.test, ast.Attribute) and node.test.attr == type_checking:
+        if isinstance(node.test.value, ast.Name) and node.test.value.id == typing_ns:
+            return node.body
+
+    return []
+
+
+def flatten(data: Iterable) -> list:
+    return [item for nested in data for item in nested]
+
+
+def parse_node(node: ast.AST) -> Union[dict, None]:
+    if isinstance(node, ast.Import):
+        return {"include": parse_import(node)}
+
+    if isinstance(node, ast.ImportFrom):
+        return {"include": parse_import_from(node)}
+
+    if isinstance(node, ast.If):
+        found = find_type_checking_body(node)
+        parsed = flatten(parse_imports(f) for f in found)
+
+        if not parsed:
+            return None
+
+        return {"exclude": parsed}
+
+    return None
+
+
 def parse_module(path: Path) -> ast.AST:
     with open(path.as_posix(), "r", encoding="utf-8", errors="ignore") as f:
         tree = ast.parse(f.read(), path.name)
@@ -42,14 +79,17 @@ def parse_module(path: Path) -> ast.AST:
 def extract_imports(path: Path) -> List[str]:
     tree = parse_module(path)
 
-    return [i for node in ast.walk(tree) for i in parse_imports(node) if i is not None]
+    nodes = (parse_node(n) for n in ast.walk(tree))
+    parsed_nodes = [n for n in nodes if n is not None]
 
+    includes = [i for n in parsed_nodes for i in n.get("include", [])]
+    excludes = {i for n in parsed_nodes for i in n.get("exclude", [])}
 
-def extract_and_flatten(py_modules: Iterable) -> Set[str]:
-    extracted = (extract_imports(m) for m in py_modules)
-    flattened = (i for imports in extracted for i in imports)
+    return [i for i in includes if i not in excludes]
 
-    return set(flattened)
+
+def extract_and_flatten(py_modules: Iterable) -> Set[str]:
+    return {i for m in py_modules for i in extract_imports(m)}
 
 
 def is_python_file(path: Path) -> bool:

projects/poetry_polylith_plugin/pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "poetry-polylith-plugin"
-version = "1.45.2"
+version = "1.46.0"
 description = "A Poetry plugin that adds tooling support for the Polylith Architecture"
 authors = ["David Vujic"]
 homepage = "https://davidvujic.github.io/python-polylith-docs/"

projects/polylith_cli/pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "polylith-cli"
-version = "1.39.0"
+version = "1.40.0"
 description = "Python tooling support for the Polylith Architecture"
 authors = ['David Vujic']
 homepage = "https://davidvujic.github.io/python-polylith-docs/"