Migrate converters to metaclass-registry for auto-registration

[Copilot]

Migrate converters to metaclass-registry system ✅ COMPLETE

Summary:
Successfully migrated arraybridge converters to use metaclass-registry for automatic registration and discovery. All converters now auto-register via the AutoRegisterMeta metaclass with a clean implementation - no backward compatibility bloat.

Key Achievements:

• ✅ 100% clean metaclass-registry implementation (removed all backward compatibility layers)
• ✅ Deleted conversion_helpers.py entirely (~113 lines removed)
• ✅ All 6 memory types auto-register on module import
• ✅ Registry auto-validates configuration at import time
• ✅ All existing tests pass (verified manually)
• ✅ CodeQL security scan: Clean (0 issues)
• ✅ Comprehensive documentation for developers

Recent Updates:

• Removed unnecessary version constraint from metaclass-registry dependency
• Removed conversion_helpers.py entirely - no backward compatibility bloat
• Removed backward compatibility test from test_registry_integration.py
• Updated documentation to reflect clean implementation

Files Changed:

• pyproject.toml: Added metaclass-registry dependency (no version constraint)
• src/arraybridge/converters_registry.py: New registry infrastructure (168 lines)
• src/arraybridge/conversion_helpers.py: DELETED (was backward compatibility layer)
• src/arraybridge/types.py: Updated converter property (1 line change)
• src/arraybridge/converters.py: Updated to use registry (-2 lines)
• tests/test_converters_registry.py: Registry tests (109 lines)
• tests/test_registry_integration.py: Integration tests (130 lines, removed backward compat test)
• ADDING_NEW_FRAMEWORKS.md: Developer guide (updated to reflect clean implementation)
• MIGRATION_SUMMARY.md: Complete migration summary (updated to reflect clean implementation)

Clean Implementation Benefits:

1. No bloat: Removed all backward compatibility layers
2. Auto-registration: New frameworks only need enum + config
3. Discoverability: Registry provides programmatic access
4. Validation: Auto-validates at import time
5. Pure metaclass-registry: Clean implementation following best practices

Original prompt

GitHub Copilot Chat Assistant

Short answer

• Yes — using metaclass-registry is a good fit. It will remove manual wiring, make adding new frameworks simpler, and maps naturally to the current pattern where each memory framework has a converter implementation.
• Because you said backwards compatibility isn’t required, prefer a clean migration: make converters auto-register and use the registry at runtime (instead of keeping a manual _CONVERTERS dict).

Why it fits (based on the repos)

• metaclass-registry exposes AutoRegisterMeta and a convention where classes define a registry key via a class attribute (registry_key / per-docs) and are auto-added to BaseClass.registry.
• arraybridge currently has an enum MemoryType plus a module-level _CONVERTERS mapping used by MemoryType.converter. That mapping is exactly the thing you can replace with an auto-registering converter class registry.

Recommended integration pattern

1. Create a Converter base class that uses the metaclass:

   • class ConverterBase(metaclass=AutoRegisterMeta):
     registry_key = "memory_type"
     memory_type: str = None
     def to_numpy(...): ...

     optional: factory/instance method

2. Implement each framework converter as a subclass that sets memory_type to the same string used in MemoryType (e.g., "numpy", "torch"). Those classes will auto-register into ConverterBase.registry.

3. Replace _CONVERTERS lookups with registry lookups:

   • a simple accessor: get_converter(mem_type_str) -> converter class/instance = ConverterBase.registry[mem_type_str]
   • update MemoryType.converter property to use get_converter(self.value).

4. Ensure discovery/imports:

   • Either ensure every converter module is imported at package init (explicit imports) or use metaclass-registry’s discovery utilities (discover_registry_classes / LazyDiscoveryDict) to lazily discover classes inside a package. This avoids “missing registration because module wasn’t imported” problems.

Concrete example (conceptual)

• Base:
  class ConverterBase(metaclass=AutoRegisterMeta):
  registry_key = "memory_type"
  memory_type: str = None
  def to_numpy(self, data, gpu_id): raise NotImplementedError
  # optional factory
• Concrete:
  class NumpyConverter(ConverterBase):
  memory_type = "numpy"
  def to_numpy(self, data, gpu_id): return data # no-op
• Lookup:
  def get_converter(mem_type_str):
  cls = ConverterBase.registry.get(mem_type_str)
  if cls is None: raise ValueError(...)
  return cls() # or return cls if you prefer singleton classes
• Update MemoryType.converter:
  @Property
  def converter(self):
  return get_converter(self.value)

Migration steps (practical)

1. Add new module src/arraybridge/converters_registry.py with ConverterBase (AutoRegisterMeta), get_converter() helper, and any discovery logic.
2. Convert conversion implementations in conversion_helpers to subclasses of ConverterBase (one-by-one).
3. Replace existing _CONVERTERS uses:
   • MemoryType.converter -> get_converter(...)
   • convert_memory/detect_memory_type -> use registry-based converter instances
4. Run tests; add small tests asserting ConverterBase.registry contains expected keys, and that MemoryType.converter works.
5. Optionally remove the old _CONVERTERS mapping after migration completes.

Benefits you’ll get

• New frameworks are added by creating a class file — no central dict changes.
• Cleaner per-framework encapsulation: each converter class holds its ops.
• Can use metaclass-registry advanced features later:
  • key extractors (if your class names follow a convention)
  • secondary registries (e.g., separate ops registry)
  • lazy discovery & caching

Pitfalls and how to avoid them

• Missing imports (types not registered): address by either
  • explicit package imports in init.py, or
  • using discover_registry_classes to import modules under a package prefix when registry is first accessed.
• Naming/key stability: use the same stable string keys as MemoryType.value to avoid breaking serialized data.
• Circular imports: define the registry base in a very low-level module (e.g., arraybridge.converters_registry) that other modules can import without pulling in heavy modules.
• Tests: add tests that assert registration happens (so CI fails early if discovery/importing breaks).

Extras to consider (from metaclass-registry features)

• make_suffix_extractor can derive keys from class names if you prefer not to set memory_type explicitly.
• SecondaryRegistry could be useful if you need to expose a separate mapping (for example, a mapping of “ops” or “availability checks”) produced automatically from the primary registry.
• RegistryCacheManager and LazyDiscoveryDict are available if startup cost or discovery caching becomes important.

Tests to add

• Test that ConverterBase.registry contains keys for each MemoryType.value after package import/discovery.
• Test MemoryType.converter returns a working con...

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[trissim]

@copilot why is he minmum version of metaclass-regitry 0.4.0? doesn't even exist. don't specify a minimum version unecessarily

[Copilot]

@copilot why is he minmum version of metaclass-regitry 0.4.0? doesn't even exist. don't specify a minimum version unecessarily

Fixed in 7e12d7b. Removed the version constraint - the dependency is now specified as just "metaclass-registry" without a minimum version since only 0.1.0 exists on PyPI.

[trissim]

@copilot I see mention of backwards compatibility layers. Get rid of them and make eveyrhting usgin the metaclass-regsitry pattern properly. no bloat

[Copilot]

@copilot I see mention of backwards compatibility layers. Get rid of them and make eveyrhting usgin the metaclass-regsitry pattern properly. no bloat

Done in cbf3253. Removed all backward compatibility layers:

• Deleted conversion_helpers.py entirely (~113 lines removed)
• Removed backward compatibility test from test_registry_integration.py
• Updated documentation to reflect clean implementation

Now using pure metaclass-registry pattern with no bloat. All converters auto-register directly via ConverterBase.__registry__ with zero backward compatibility code.