Look up each module name without a package version only once

aikido_zen/background_process/packages.py

@@ -56,9 +56,22 @@ def is_version_supported(version, required_version):
 
 # packages store, uses python's built in GlobalInterpreterLock (GIL)
 packages_store = {}
+# version() scans all of sys.path, so names it cannot find (re, json) are looked up once.
+names_without_version = set()
 
 
 class PackagesStore:
+    @staticmethod
+    def add_installed_package(name):
+        if name in names_without_version or name in packages_store:
+            return
+        version = None
+        try:
+            version = importlib_metadata.version(name)
+        except importlib_metadata.PackageNotFoundError:
+            pass
+        PackagesStore.add_package(name, version)
+
     @staticmethod
     def export():
         result = []
@@ -70,6 +83,9 @@ def export():
 
     @staticmethod
     def add_package(package, version):
+        if not version:
+            names_without_version.add(package)
+            return
         packages_store[package] = {
             "name": package,
             "version": version,
@@ -91,9 +107,13 @@ def clear():
         for package in packages_store.values():
             package["cleared"] = True
 
+    @staticmethod
+    def clear_names_without_version():
+        names_without_version.clear()
+
     @staticmethod
     def import_list(imported_packages):
         for package in imported_packages:
-            if PackagesStore.get_package(package["name"]):
+            if package["name"] in packages_store:
                 continue
             packages_store[package["name"]] = package

aikido_zen/sinks/builtins_import.py

@@ -1,7 +1,5 @@
 from aikido_zen.sinks import on_import, patch_function, after
 import contextvars
-import importlib.metadata
-from importlib.metadata import PackageNotFoundError
 from aikido_zen.background_process.packages import PackagesStore
 
 running_import_scan = contextvars.ContextVar("running_import_scan", default=False)
@@ -30,16 +28,7 @@ def _import(func, instance, args, kwargs, return_value):
             # Avoid circular dependencies, this is a double safety-check for if contextvar check fails.
             return
 
-        if PackagesStore.get_package(name):
-            return
-
-        version = None
-        try:
-            version = importlib.metadata.version(name)
-        except PackageNotFoundError:
-            pass
-        if version:
-            PackagesStore.add_package(name, version)
+        PackagesStore.add_installed_package(name)
     finally:
         running_import_scan.set(False)
 

aikido_zen/sinks/tests/builtins_import_test.py

@@ -1,3 +1,6 @@
+import importlib.metadata
+from unittest.mock import patch
+
 import pytest
 
 import aikido_zen
@@ -10,6 +13,7 @@
 @pytest.fixture(autouse=True)
 def run_around_tests():
     PackagesStore.clear()
+    PackagesStore.clear_names_without_version()
 
 
 def test_flask_import():
@@ -24,20 +28,37 @@ def test_django_import():
     assert PackagesStore.get_package("django")["version"] == "4.0"
 
 
+def test_name_without_a_distribution_is_looked_up_once():
+    with patch(
+        "importlib.metadata.version", wraps=importlib.metadata.version
+    ) as version:
+        for _ in range(10):
+            import json
+
+    assert [c.args for c in version.call_args_list] == [("json",)]
+    assert PackagesStore.get_package("json") is None
+
+
 def test_recursive_package_store(monkeypatch):
     """Test that recursive imports during package scanning don't cause max recursion depth errors."""
 
-    def recursive_get_package(name):
+    calls = []
+
+    def recursive_add_installed_package(name):
         """Recursively add package and its dependencies to PackagesStore."""
+        calls.append(name)
         import flask
 
     PackagesStore.clear()
-    monkeypatch.setattr(PackagesStore, "get_package", recursive_get_package)
+    monkeypatch.setattr(
+        PackagesStore, "add_installed_package", recursive_add_installed_package
+    )
 
     import flask
 
     # Restore the original method after the test
     monkeypatch.undo()
+    assert calls == ["flask"]
 
 
 def test_recursive_package_store_2(monkeypatch):