Max Isbey
cb7c68cf84
Every package init in the SDK resolves its submodules on attribute access except four docstring-only leaves - mcp.os.posix, mcp.os.win32, mcp.server.auth.handlers and mcp.server.auth.middleware - so a chain like `import mcp; mcp.server.auth.handlers.token` stopped resolving even though `mcp.client.stdio` and friends do. Give them the same lazy fallback, so "attribute chains still resolve" is true without a footnote (explicit imports remain the supported form), and pin one chain through each in the ratchet.
79 lines
3.6 KiB
Python
79 lines
3.6 KiB
Python
"""`mcp.shared._lazy`: lazy exports and submodules resolved on attribute access."""
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import subprocess
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import sys
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from types import ModuleType
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import pytest
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from inline_snapshot import snapshot
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import tests.shared.lazy_submodule_fixture as fixture_pkg
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def test_package_attribute_imports_the_submodule_of_that_name():
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"""SDK-defined: `pkg.<name>` imports `pkg.<name>` on first touch and binds it on the package."""
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submodule = getattr(fixture_pkg, "fine")
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assert isinstance(submodule, ModuleType)
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assert submodule.MARKER == "ok"
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assert submodule is sys.modules["tests.shared.lazy_submodule_fixture.fine"]
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assert vars(fixture_pkg)["fine"] is submodule
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def test_lazy_export_is_loaded_once_and_cached_in_the_namespace():
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"""SDK-defined: a lazy export runs its loader on first access, then reads as a plain attribute."""
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assert fixture_pkg.ANSWER == 42
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assert fixture_pkg.ANSWER == 42
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assert fixture_pkg.load_calls == 1
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assert vars(fixture_pkg)["ANSWER"] == 42
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def test_dir_lists_exports_and_submodules_but_not_the_lazy_machinery():
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"""SDK-defined: `dir(pkg)` reports the lazy exports and real submodules, and hides the
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helper's own bindings so the namespace looks the way an eager module would."""
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listing = dir(fixture_pkg)
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assert {"ANSWER", "fine", "broken", "load_calls"} <= set(listing)
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assert {"__getattr__", "__dir__", "_lazy_module_attrs"}.isdisjoint(listing)
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def test_missing_name_raises_attribute_error_without_importing_anything():
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"""SDK-defined: a name that is neither an export nor a real submodule is a plain
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AttributeError; nothing is speculatively imported for it."""
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with pytest.raises(AttributeError):
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getattr(fixture_pkg, "no_such_submodule")
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assert "tests.shared.lazy_submodule_fixture.no_such_submodule" not in sys.modules
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def test_dunder_probe_raises_attribute_error_without_a_submodule_search():
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"""SDK-defined: dunder names are protocol probes, never lazy names."""
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with pytest.raises(AttributeError):
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getattr(fixture_pkg, "__no_such_dunder__")
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def test_submodule_with_a_missing_dependency_surfaces_the_real_import_error():
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"""SDK-defined: an existing submodule that fails to import raises its own error, not AttributeError."""
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with pytest.raises(ModuleNotFoundError) as exc_info:
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getattr(fixture_pkg, "broken")
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assert exc_info.value.name == "definitely_not_installed_dependency_xyz"
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def test_bare_import_mcp_still_resolves_deep_submodule_chains():
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"""SDK-defined: after only `import mcp`, `mcp.client.stdio.stdio_client` etc. still resolve,
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and each package's `dir()` lists submodules that were never imported explicitly.
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A fresh interpreter is required: this process already imported those modules.
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"""
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probe = (
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"import mcp\n"
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"print([mcp.client.stdio.stdio_client.__name__, mcp.server.stdio.stdio_server.__name__,\n"
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" mcp.shared.memory.__name__, mcp.os.posix.utilities.__name__,\n"
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" mcp.os.win32.utilities.__name__, mcp.server.auth.handlers.token.__name__,\n"
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" mcp.server.auth.middleware.auth_context.__name__,\n"
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" 'stdio' in dir(mcp.client), 'stdio' in dir(mcp.server), 'exceptions' in dir(mcp.shared)])\n"
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)
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result = subprocess.run([sys.executable, "-c", probe], capture_output=True, text=True, check=False, timeout=20)
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assert result.returncode == 0, result.stderr
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assert result.stdout == snapshot("""\
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['stdio_client', 'stdio_server', 'mcp.shared.memory', 'mcp.os.posix.utilities', 'mcp.os.win32.utilities', \
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'mcp.server.auth.handlers.token', 'mcp.server.auth.middleware.auth_context', True, True, True]
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""")
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