Max Isbey
1f3fbc7ca3
Three implementations of lazy module attributes had grown: the hand-rolled __getattr__/__dir__ in mcp/__init__.py, the submodule fallback factory used by the four package inits, and a one-name __getattr__ in mcp.server.elicitation. They shared two problems. An unconditional module-level __getattr__ is visible to type checkers, so pyright typed every misspelled `mcp.<name>` (and `mcp.client.<name>`, ...) as `object` instead of reporting it. And the submodule fallback ran a filesystem find_spec on every attribute miss and speculatively imported whatever matched, so a name sweep (cloudpickle's whichmodule, hasattr probes) could import real submodules as a side effect, while dir(mcp.client) no longer listed submodules it would happily resolve. mcp.shared._lazy.lazy_module_attrs now serves all of them: lazy exports (a `(module, attr)` pair or a zero-argument loader, resolved once and cached in the namespace) plus known submodules (an explicit set, or the package's real submodules listed once on first need). A miss is a plain AttributeError with no search and no import, and __dir__ reports the exports and submodules. Every caller binds the pair under `if not TYPE_CHECKING:`, so attribute typos are pyright errors again while the TYPE_CHECKING mirrors keep the real names typed. The mcp.server.auth package gets the same fallback so qualified annotations such as `mcp.server.auth.provider.TokenVerifier` resolve on demand. The elicitation gate's wire-schema type is resolved through the same mechanism from a cached accessor, so validating rendered schemas no longer re-executes the wire-package import on every call.
53 lines
1.9 KiB
Python
53 lines
1.9 KiB
Python
"""`mcp.server.elicitation` module-level behaviour."""
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import builtins
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from collections.abc import Mapping, Sequence
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from types import ModuleType
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from unittest.mock import patch
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import mcp_types._v2025_11_25 as wire
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from pydantic import BaseModel
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from mcp.server import elicitation
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from mcp.server.elicitation import render_elicitation_schema
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def test_wire_schema_gate_type_is_still_reachable_on_the_module():
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"""`PrimitiveSchemaDefinition` used to be bound here by a module-level import; it now
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resolves lazily to the same class, and `dir()` still lists it."""
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assert elicitation.PrimitiveSchemaDefinition is wire.PrimitiveSchemaDefinition
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assert "PrimitiveSchemaDefinition" in dir(elicitation)
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def test_rendering_schemas_repeatedly_executes_no_further_imports():
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"""The wire-schema gate type is resolved once; rendering more schemas afterwards never
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runs another import statement (the import cost is a one-time first-use bill, not a
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per-call one)."""
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class Prompt(BaseModel):
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name: str
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age: int = 0
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render_elicitation_schema(Prompt) # warm-up: pays the one-time wire-package import
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real_import = builtins.__import__
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import_calls: list[str] = []
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def counting_import(
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name: str,
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globals: Mapping[str, object] | None = None,
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locals: Mapping[str, object] | None = None,
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fromlist: Sequence[str] = (),
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level: int = 0,
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) -> ModuleType:
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import_calls.append(name)
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return real_import(name, globals, locals, fromlist, level)
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with patch.object(builtins, "__import__", counting_import):
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for _ in range(20):
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render_elicitation_schema(Prompt)
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# pydantic runs its own function-level imports while generating a schema; the SDK's
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# gate (the wire package) must not add any of ours.
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assert [name for name in import_calls if name.startswith("mcp")] == []
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