fix: resolve lazy login imports relative to the loaded package

lm15/__init__.py

@@ -293,12 +293,12 @@
 # nothing on the request path needs them, and lm15's import time is a
 # promise, so these names resolve lazily (PEP 562).
 _LAZY_LOGIN = {
-    "Auth": ("lm15.login", "Auth"),
-    "AsyncAuth": ("lm15.login", "AsyncAuth"),
-    "BoundClient": ("lm15.login", "BoundClient"),
-    "TerminalUI": ("lm15.login", "TerminalUI"),
-    "providers": ("lm15.login", "providers"),
-    "connect": ("lm15.interactive", "connect"),
+    "Auth": (".login", "Auth"),
+    "AsyncAuth": (".login", "AsyncAuth"),
+    "BoundClient": (".login", "BoundClient"),
+    "TerminalUI": (".login", "TerminalUI"),
+    "providers": (".login", "providers"),
+    "connect": (".interactive", "connect"),
 }
 
 
@@ -308,6 +308,6 @@ def __getattr__(name: str):
         raise AttributeError(f"module 'lm15' has no attribute {name!r}")
     import importlib
 
-    value = getattr(importlib.import_module(target[0]), target[1])
+    value = getattr(importlib.import_module(target[0], __package__), target[1])
     globals()[name] = value
     return value

lm15/login/flows/__init__.py

@@ -52,7 +52,7 @@ def _account_flow(provider: str) -> ProviderFlow | None:
         return None
     import importlib
 
-    module = importlib.import_module(f"lm15.login.flows.{module_name}")
+    module = importlib.import_module(f".{module_name}", __package__)
     for name in dir(module):
         candidate = getattr(module, name)
         if isinstance(candidate, type) and issubclass(candidate, ProviderFlow) and candidate is not ProviderFlow:

tests/test_api_papercuts.py

@@ -98,3 +98,42 @@ def test_factories_stay_in_types(self):
 
         for name in self.FACTORY_NAMES:
             assert callable(getattr(types, name))
+
+    @pytest.mark.parametrize("surface", ["exports", "flows"])
+    def test_lazy_imports_use_the_loaded_package(self, surface):
+        import subprocess
+        import sys
+        from pathlib import Path
+
+        code = """
+import importlib.util
+import sys
+from pathlib import Path
+
+root = Path(sys.argv[1])
+sys.modules['lm15'] = None  # No unrelated top-level installation may be used.
+spec = importlib.util.spec_from_file_location(
+    'vendored_lm15', root / '__init__.py', submodule_search_locations=[str(root)],
+)
+package = importlib.util.module_from_spec(spec)
+sys.modules[spec.name] = package
+spec.loader.exec_module(package)
+assert 'vendored_lm15.login' not in sys.modules
+if sys.argv[2] == 'exports':
+    for name in package.__all__:
+        getattr(package, name)
+    from vendored_lm15.login import Auth
+    assert package.Auth is Auth
+    assert package.connect.__module__ == 'vendored_lm15.interactive'
+else:
+    from vendored_lm15.login.flows import descriptor, flow, ProviderFlow
+    assert descriptor('xai').id == 'xai'
+    assert isinstance(flow('xai', 'device'), ProviderFlow)
+    assert type(flow('xai', 'device')).__module__ == 'vendored_lm15.login.flows.xai'
+"""
+        result = subprocess.run(
+            [sys.executable, "-I", "-c", code,
+             str(Path(__file__).resolve().parents[1] / "lm15"), surface],
+            capture_output=True, text=True, encoding="utf-8", timeout=30,
+        )
+        assert result.returncode == 0, result.stderr