feat: implement kernels info

[sayakpaul]

Fixes #674

Example:

kernels info kernels-community/flash-attn3 

Repository: kernels-community/flash-attn3
Revision: v1
Name: flash-attn3
Version: 1
License: BSD-3-Clause
Upstream: -
Source: -
Python dependencies: -
Backends: cuda
Variants:

torch-stable-abi29-cu128-x86_64-linux: CPU (x86_64) does not match system CPU (aarch64)
torch-stable-abi29-cu126-x86_64-linux: CPU (x86_64) does not match system CPU (aarch64)
torch-stable-abi29-cu130-x86_64-linux: CPU (x86_64) does not match system CPU (aarch64)
torch211-cxx11-cu128-x86_64-linux: CPU (x86_64) does not match system CPU (aarch64)
torch210-cxx11-cu128-x86_64-linux: CPU (x86_64) does not match system CPU (aarch64)
torch212-cxx11-cu130-x86_64-linux: CPU (x86_64) does not match system CPU (aarch64)
torch211-cxx11-cu130-x86_64-linux: CPU (x86_64) does not match system CPU (aarch64)
torch210-cxx11-cu130-x86_64-linux: CPU (x86_64) does not match system CPU (aarch64)

(tested on a Macbook)

I decided to add info on the supported/unsupported variants for comprehensive info reporting. Can drop it if needed.

[HuggingFaceDocBuilderDev]

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[github-actions]

Coverage report — kernels/

Measured on: Python 3.10 / Torch 2.12.0.
Other CI configurations are not included in this number.
Hardware-gated code paths (ROCm/XPU/NPU/Darwin/Windows) are excluded or unreachable on the Linux+CUDA runner.

Total coverage: 84.6% — threshold: 80% — ✅

Per-file breakdown

Name	Stmts	Miss	Cover	Missing
src/kernels/__init__.py	10	0	100%
src/kernels/_system.py	6	1	83%	10
src/kernels/_versions.py	63	7	89%	46, 49, 52-53, 56-57, 100
src/kernels/backends.py	194	55	72%	40, 44, 48-51, 68, 90, 108, 117, 121, 125-127, 148, 170, 181, 188-191, 201, 205-225, 233, 256-276
src/kernels/compat.py	8	1	88%	5
src/kernels/deps.py	54	4	93%	58-59, 95, 98
src/kernels/layer/__init__.py	6	0	100%
src/kernels/layer/_interval_tree.py	103	4	96%	23, 52, 147, 150
src/kernels/layer/device.py	48	14	71%	42, 47-49, 91, 96-98, 101, 149, 152, 155-157
src/kernels/layer/func.py	81	7	91%	81, 111, 183, 301, 307, 320, 338
src/kernels/layer/globals.py	5	0	100%
src/kernels/layer/kernelize.py	74	8	89%	255, 281, 289-290, 296, 300, 316-318
src/kernels/layer/layer.py	210	16	92%	167, 210, 216, 229, 337, 417-418, 430, 439, 447, 458, 487, 491, 504, 557, 587
src/kernels/layer/mode.py	14	0	100%
src/kernels/layer/repos.py	130	34	74%	27, 33, 36-41, 61-62, 68, 71-74, 88, 92, 101-102, 108, 111-114, 121-122, 128, 131-134, 141-142, 148, 151-154, 235
src/kernels/lockfile.py	71	46	35%	37-104, 108-131
src/kernels/status.py	49	2	96%	23, 81
src/kernels/utils.py	301	55	82%	65, 77-81, 87-88, 218, 222, 225, 287, 295, 334-335, 373, 404, 409, 444, 673, 676, 678, 684, 697-698, 719-731, 735-742, 750, 754-764, 768-775, 813, 817, 836, 838
src/kernels/variants.py	262	19	93%	56, 87, 108, 138, 247-248, 289, 291, 371-378, 384-390, 421-427, 439-445, 534-536
src/kernels/verify.py	88	1	99%	32
TOTAL	1777	274	85%

Updated by the Test kernels workflow on commit 0708d5cdc98ce364bf701b5d83241d614a800d97.

[danieldk]

Nice! Added some comments.

[danieldk]

This has strong overlap with the existing kernels versions subcommand, I would therefore leave it out (always make orthogonal functions). Also, since some kernels accumunate(d) a lot of variants over time, it would push away all the other information.

[sayakpaul]

Can you elaborate more on this suggestion? Didn't quite get what's wanted.

[sayakpaul]

Ah got it.