Fix pybind API and docs

[mergennachin]

Summary of Changes to runtime/init.py

This PR fixes two critical bugs and improves documentation in the Python runtime API.

Bug Fixes

1. Fix isinstance(data, BinaryIO) Check for File-Like Objects

Problem: When loading a program from file-like objects (e.g., io.BytesIO), the runtime would fail with a TypeError because isinstance(data, BinaryIO) doesn't work. BinaryIO is a typing protocol, not a concrete class, so isinstance() checks always return False.

Fix (runtime/init.py:320-322):
elif isinstance(data, BinaryIO): # Never matched!
data_bytes = data.read()

elif hasattr(data, "read"): # Duck typing approach
data_bytes = data.read()

Impact: Users can now correctly load programs from BytesIO, file handles, and other file-like objects.

Regression Test: Added test_load_program_with_file_like_objects() in runtime/test/test_runtime.py to validate BytesIO, bytes, and bytearray loading.

2. Fix ETDump Parameters Ignored When Loading From Bytes/Buffer

Problem: When loading programs from bytes, bytearray, or file-like objects, the enable_etdump and debug_buffer_size parameters were hardcoded to False and 0, completely ignoring user-provided values. This made ETDump profiling impossible for in-memory program loading.

Fix (runtime/init.py:327-332):
p = self._legacy_module._load_program_from_buffer(
data_bytes,
enable_etdump=False, # Hardcoded!
debug_buffer_size=0, # Hardcoded!
program_verification=verification,
)

p = self._legacy_module._load_program_from_buffer(
data_bytes,
enable_etdump=enable_etdump, # Use provided parameter
debug_buffer_size=debug_buffer_size, # Use provided parameter
program_verification=verification,
)

Impact: ETDump profiling now works correctly for all program loading paths (file path, bytes, bytearray, file-like objects), not just file paths.

Regression Test: Added test_etdump_params_with_bytes_and_buffer() in runtime/test/test_runtime_etdump_gen.py to validate parameter passing for bytes, bytearray, and BytesIO.

Documentation Improvements

Fixed Docstring Errors

• BackendRegistry.is_available(): Fixed copy-paste error in docstring (was describing registered_backend_names instead)
• Program.metadata(): Fixed return type description (was generic, now specific to MethodMeta)
• Runtime.load_program(): Added missing documentation for enable_etdump and debug_buffer_size parameters

Enhanced API Documentation

• Method.execute(): Clarified input/output types (torch.Tensor objects)
• Method.metadata: Improved description of what metadata includes
• Runtime class: Added Attributes section documenting backend_registry and operator_registry

Improved Module-Level Examples

• Fixed ETDump example: Changed debug_buffer_size=1e7 to int(1e7) (correct type)
• Added backend/operator introspection example: Shows how to query available backends and operators
• Made example output generic: Removed specific backend names and added build-dependent notes

Testing

All tests pass (7/7) including both new regression tests:
✅ test_load_program_with_file_like_objects - Validates BytesIO bug fix
✅ test_etdump_params_with_bytes_and_buffer - Validates ETDump parameter bug fix

Impact

These fixes improve the robustness and usability of the Python runtime API:

• File-like object support now works as documented
• ETDump profiling now works for all loading methods
• Documentation is more accurate and comprehensive

[pytorch-bot]

🔗 Helpful Links

🧪 See artifacts and rendered test results at hud.pytorch.org/pr/pytorch/executorch/15051

• 📄 Preview Python docs built from this PR

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❗ 1 Active SEVs

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• [ROCm][CI] Machines under the label linux.rocm.gpu.2 are undergoing maintenance.

❌ 6 New Failures, 7 Unrelated Failures

As of commit 376c281 with merge base d00279d ():

NEW FAILURES - The following jobs have failed:

• pull / test-multimodal-linux (gemma3-4b) / linux-job (gh)
  RuntimeError: Command docker exec -t 13016f19d2207de7e5fa72cbc935cade293a2d487998040193b76131d2a77484 /exec failed with exit code 139
• pull / test-qnn-wheel-packages-linux (3.10) / linux-job (gh)
  RuntimeError: Command docker exec -t 25731f4e0dd02ab0b7ba8b58d54dbd9cba3b575a564b72c2a9411f8431743883 /exec failed with exit code 1
• pull / test-qnn-wheel-packages-linux (3.11) / linux-job (gh)
  RuntimeError: Command docker exec -t 2bc0401a0f199d4f137c0ebf80332d2bbb76b0d6ff216d3f90d8c2f6b957f901 /exec failed with exit code 1
• pull / test-qnn-wheel-packages-linux (3.12) / linux-job (gh)
  RuntimeError: Command docker exec -t ec69f6a2e37ef145ba9e6d0d4ddbf44e22a63e93064b859fa5388af0006dd4b8 /exec failed with exit code 1
• pull / unittest / windows / windows-job (gh)
  runtime/test/test_runtime_etdump_gen.py::RuntimeETDumpGenTest::test_etdump_params_with_bytes_and_buffer
• pull / unittest-editable / windows / windows-job (gh)
  runtime/test/test_runtime_etdump_gen.py::RuntimeETDumpGenTest::test_etdump_params_with_bytes_and_buffer

FLAKY - The following jobs failed but were likely due to flakiness present on trunk:

• pull / test-openvino-linux / linux-job (gh) (detected as infra flaky with no log or failing log classifier)
• pull / test-static-llama-qnn-linux / linux-job (gh) (detected as infra flaky with no log or failing log classifier)
• pull / unittest / linux / linux-job (gh) (matched linux rule in flaky-rules.json)
  The runner has received a shutdown signal. This can happen when the runner service is stopped, or a manually started runner is canceled.
• pull / unittest-editable / macos / macos-job (gh) (similar failure)
  RuntimeError: Command bash /Users/ec2-user/runner/_work/_temp/exec_script failed with exit code 1

BROKEN TRUNK - The following jobs failed but were present on the merge base:

👉 Rebase onto the `viable/strict` branch to avoid these failures

• pull / unittest / macos / macos-job (gh) (trunk failure)
  RuntimeError: Command bash /Users/ec2-user/runner/_work/_temp/exec_script failed with exit code 1
• pull / unittest-buck / macos / macos-job (gh) (trunk failure)
  RuntimeError: Command bash /Users/ec2-user/runner/_work/_temp/exec_script failed with exit code 1
• pull / unittest-editable / linux / linux-job (gh) (trunk failure)

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