CoreOwnership.md

Core ownership

SharpRuntime::Core.Base is the acyclic foundation used by the physical runtime modules. SharpRuntime::Core is a compatibility umbrella over Core.Base, Console, Uri, and TimeZone; internal modules must depend on the narrow physical targets instead of the umbrella.

Public include spellings and System::* namespaces do not determine physical ownership. Ownership follows dependency direction: a type remains in Core.Base when moving it to a higher module would make foundational primitives depend upward or create a static-library cycle.

Foundation groups

Group	Representative types	Ownership reason
Primitive/value types	Boolean, integer and floating-point types, Decimal, Guid, DateOnly, DateTime, TimeOnly, TimeSpan	Used throughout every higher layer.
Object and string model	Object, ValueType, String, StringComparer, arrays, tuples and nullable types	Defines the common public vocabulary of the runtime.
Memory/span model	Span, ReadOnlySpan, Memory, ReadOnlyMemory, ArraySegment, SequencePosition	Required by primitive parsing, text and buffers.
Base exceptions	Exception, SystemException, argument/format/overflow and platform exceptions	Higher modules expose these exceptions from public APIs.
Attributes and delegate helpers	Attribute, Action, Func, EventHandler, Delegate, MulticastAction	Shared header-level contracts with no valid higher owner.
Environment/runtime compatibility	Environment, OperatingSystem, AppDomain, GC/reflection stubs	Root System compatibility surface; implementations depend only on the foundation.

Extracted optional clusters

Component	Owned surface	Direct dependency
SharpRuntime::Console	Console* headers and Console.cpp	Core.Base
SharpRuntime::Uri	Uri* headers, URI enums/exceptions and Uri.cpp	Core.Base
SharpRuntime::TimeZone	TimeZone, TimeZoneInfo, their rules and exceptions	Core.Base

These components retain their original include paths. The compatibility SharpRuntime::Core target enables all three for existing consumers.

Intentional cross-namespace foundation types

Include path owned by Core.Base	Reason
System/Buffers/MemoryHandle.hpp	System::Memory and ReadOnlyMemory expose it; making Core.Base depend on Buffers would reverse the base dependency.
System/Collections/Generic/IEqualityComparer.hpp	Primitive and string equality infrastructure uses it; Collections.Core depends on Core.Base.
System/Diagnostics/Stopwatch.hpp	TimeProvider and timing primitives need the lightweight clock abstraction without the process/debugging component.
System/Globalization/CharUnicodeInfo.hpp, NumberStyles.hpp, UnicodeCategory.hpp	Character and numeric primitives expose these types; Globalization depends on Core.Base.
System/IO/IOException.hpp, DirectoryNotFoundException.hpp	Environment throws DirectoryNotFoundException; moving them to IO creates Core.Base -> IO -> Core.Base.
System/Numerics/BFloat16.hpp	BitConverter exposes the value type while Numerics depends on Core.Base and Collections.Core.
System/Security/Cryptography/CryptographicException.hpp	Root conversion/parsing helpers and cryptography APIs need one base exception without reversing the cryptography dependency.
System/Text/NormalizationForm.hpp	Root string normalization APIs expose the enum while Text depends on Core.Base and Buffers.
System/Threading/LazyThreadSafetyMode.hpp	System::Lazy<T> exposes the enum while Threading depends on Core.Base.

New cross-namespace ownership in Core.Base requires a concrete cycle or public-foundation rationale in this table and must pass scripts/validate_module_boundaries.py.