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RO_E_METADATA_NAME_IS_NAMESPACE
Metadata name identifies a namespace instead of a type
RO_E_METADATA_NAME_IS_NAMESPACE is HRESULT 2147483664 (0x80000010) from winerror.h. AllStat describes it as “Name is an existing namespace rather than a typename.” In the Windows Runtime metadata, object lifetime, asynchronous operation, activation, and apartment model, the code identifies a specific failure boundary and should not be replaced by a generic COM exception.
Telemetry should preserve this result as a separate outcome rather than merging it with unrelated COM or WinRT failures.
Decisive interpretation boundary
Before choosing recovery, verify that the caller distinguishes namespace enumeration from type resolution and supplies the complete leaf type name. If this condition cannot be proven for it, stop before consuming outputs or repeating side effects.
Also confirm that all observed objects, tokens, buffers, proxies, metadata files, or ACLs belong to the current operation generation and were not retained from an earlier attempt.
Where it is encountered
- C++/WinRT, WRL,.NET projections, or native WinRT ABI calls. Record the interface, method, component version, thread, apartment, process, and correlation ID.
- Runtime-class activation, WinMD reflection, asynchronous objects, observable state, or view lifecycle.
- Cross-thread and cross-apartment handoff between UI, ASTA, STA, MTA, broker, and background work.
The immediate focus for it is a WinRT metadata request that expects a concrete runtime class, interface, enum, or delegate but receives a namespace path. Keep it attached to that operation; the same numeric severity outside the owning API does not supply enough context.
Correct handling and recovery
Append or select the intended type, or switch to a namespace-enumeration API. Do not attempt activation with the namespace token.
An unchanged retry loop for it can duplicate effects, deepen reentrancy, or hide an invalid lifetime transition.
Difference from nearby HRESULTs
It confirms that the prefix exists; RO_E_METADATA_NAME_NOT_FOUND says neither a type nor namespace matched.
A support tool discussing it should name the neighboring result only after the originating API and decisive state are known.
Lifetime, retry, and cleanup rules
After it, determine whether the current object, interface pointer, call context, token, stream, metadata reader, asynchronous operation, or access-control instance remains valid. Release only resources owned by the failing attempt, cancel callbacks through their documented mechanism, and avoid double close, double commit, repeated activation, or replay of a non-idempotent remote method.
The retry policy for it should state the trigger, maximum attempts, cancellation owner, and reconciliation step for effects that may have completed elsewhere.
Developer and administrator guidance
When it crosses native, managed, scripting, RPC, or WinRT projection boundaries, preserve the unsigned 32-bit HRESULT. Unit tests for it should assert the code-specific postcondition and resource ownership, not merely that an exception was thrown.
After it, avoid broad permission grants or system-wide resets unless code-specific evidence proves a global configuration problem. Define who owns retry, cancellation, cleanup, policy changes, package repair, and user-facing messaging for it.
Practical scenario
A reflection tool tries to activate <code>Windows.Storage</code>. It enumerates types in that namespace and then selects <code>Windows.Storage.StorageFile</code>.
A regression test should reproduce it, assert the raw HRESULT and all relevant outputs, then correct only the decisive condition and verify the intended success or neighboring failure result.
References
- Microsoft: C++/WinRT error handling
- Microsoft: concurrency and asynchronous operations
- Microsoft: WinMD files
- Microsoft: IAgileObject
- Microsoft: COM apartments
- Microsoft: HRESULT values
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