Fix case of empty package directory under usethis tool import-linter

nathanjmcdougall · nathanjmcdougall · commit 4bc18728e6de · 2025-12-23T20:32:19.000+13:00
diff --git a/pyproject.toml b/pyproject.toml
@@ -136,8 +136,8 @@ lint.select = [
 lint.ignore = [ "PLR2004", "S101", "SIM108" ]
 lint.per-file-ignores."!tests/**/*.py" = [ "ARG002", "PT" ]
 lint.per-file-ignores."src/usethis/_ui/interface/**/*.py" = [ "PLR0913" ]
-lint.per-file-ignores."tests/**/*.py" = [ "D", "INP", "S603", "TC" ]
 
+lint.per-file-ignores."tests/**" = [ "D", "INP", "S603", "TC" ]
 lint.flake8-bugbear.extend-immutable-calls = [ "typer.Argument", "typer.Option" ]
 lint.flake8-builtins.strict-checking = true
 lint.flake8-tidy-imports.banned-api."typer.testing.CliRunner".msg = "Use `usethis._test.CliRunner` instead of `typer.CliRunner`."
diff --git a/src/usethis/_integrations/project/imports.py b/src/usethis/_integrations/project/imports.py
@@ -34,6 +34,8 @@ def get_layered_architectures(pkg_name: str) -> dict[str, LayeredArchitecture]:
 
     This is intended to inform the basis of a layer contract.
 
+    Note that the resulting dictionary may be empty if the package seems to be empty.
+
     Reference:
         https://import-linter.readthedocs.io/en/stable/contract_types.html#layers
 
diff --git a/src/usethis/_tool/impl/import_linter.py b/src/usethis/_tool/impl/import_linter.py
@@ -242,6 +242,10 @@ def get_root_packages() -> list[str] | NoConfigValue:
                             keys=["tool", "importlinter", "contracts"],
                             get_value=lambda: contracts,
                         ),
+                        # N.B. these INI sections are added via
+                        # `ini_contracts_config_items`
+                        # but there might be others so we still need to declare they
+                        # are associated with this tool based on regex.
                         Path(".importlinter"): ConfigEntry(
                             keys=[re.compile("importlinter:contract:.*")]
                         ),
@@ -271,6 +275,9 @@ def _get_layered_architecture_by_module_by_root_package(
             try:
                 layered_architecture_by_module = get_layered_architectures(root_package)
             except ImportGraphBuildFailedError:
+                layered_architecture_by_module = {}
+
+            if not layered_architecture_by_module:
                 layered_architecture_by_module = {
                     root_package: LayeredArchitecture(layers=[], excluded=set())
                 }
diff --git a/tests/usethis/_tool/impl/test_import_linter.py b/tests/usethis/_tool/impl/test_import_linter.py
@@ -156,6 +156,24 @@ def test_pyproject_toml_exists(self, tmp_path: Path):
             assert not (tmp_path / ".importlinter").exists()
             assert (tmp_path / "pyproject.toml").exists()
 
+    class TestGetConfigSpec:
+        def test_empty_src_directory(self, tmp_path: Path):
+            # Arrange: Create empty src directory with package subdirectory
+            # src/ contains mypkg/ but mypkg/ is completely empty (no __init__.py)
+            (tmp_path / "pyproject.toml").write_text('[project]\nname = "mypkg"')
+            (tmp_path / "src").mkdir()
+            (tmp_path / "src" / "mypkg").mkdir()
+            # mypkg directory is empty - no __init__.py, no files
+
+            # Act: get_config_spec should not crash with AssertionError
+            # when get_importable_packages returns empty and grimp fails
+            with change_cwd(tmp_path), files_manager():
+                config_spec = ImportLinterTool().get_config_spec()
+
+            # Assert: Should return a valid config spec with fallback contract
+            assert config_spec is not None
+            assert len(config_spec.config_items) > 0
+
 
 class TestIsINPRule:
     def test_inp_rule(self):
