Add deprecation warning for to_edge + to_backend workflow in CoreMLPa…

[mohammed-saalim]

Fixes #15960
This PR adds a deprecation warning in the CoreMLPartitioner to guide users away from the deprecated to_edge() + to_backend() workflow and toward the recommended to_edge_transform_and_lower() flow.

Changes

• Added _check_if_called_from_to_backend() method to detect deprecated workflow
• Modified partition() to log warning when deprecated flow is detected
• Added two unit tests to verify warning behavior

Pattern

Following the same pattern as #13209 (XNNPACK).

Related

This picks up the abandoned PR #15963.

cc @kimishpatel @YifanShenSZ @cymbalrush @metascroy

[pytorch-bot]

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❌ 3 New Failures

As of commit adfe544 with merge base 62d6dc1 ():

NEW FAILURES - The following jobs have failed:

• Copilot code review / Cleanup artifacts (gh)
  Process completed with exit code 1.
• pull / test-samsung-models-linux / linux-job (gh)
  RuntimeError: Command docker exec -t bbb1702502f28f14ae30f5c459894d0b27491b1537ea1c3d366735a0b5b984c0 /exec failed with exit code 1
• pull / test-samsung-quantmodels-linux / linux-job (gh)
  RuntimeError: Command docker exec -t c4b935f3a6d185fe653d7e0f721fa6981da17ac82315b4e0eaafe24047ed4f34 /exec failed with exit code 1

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[Copilot]

Pull request overview

This PR adds a deprecation warning in the CoreML partitioner to steer users away from the older to_edge() + to_backend() workflow toward to_edge_transform_and_lower(), matching the pattern already used for XNNPACK and adding tests to validate the behavior.

Changes:

• Added _check_if_called_from_to_backend() to CoreMLPartitioner to detect when partition() is invoked via the deprecated to_backend path.
• Updated CoreMLPartitioner.partition() to log a deprecation warning when the deprecated flow is detected, including context on performance implications and a docs link.
• Added two unit tests that verify the warning is emitted for to_edge() + to_backend() and not emitted when using to_edge_transform_and_lower(), and wired them into the file’s __main__ block.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
backends/apple/coreml/partition/coreml_partitioner.py	Adds stack-based detection of deprecated to_backend usage and emits a CoreML-specific deprecation warning while preserving existing partitioning behavior.
backends/apple/coreml/test/test_coreml_partitioner.py	Introduces tests that capture the CoreML partitioner logger output to assert that the deprecation warning appears only for to_edge() + to_backend() and extends the manual test runner to invoke these tests.

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[mohammed-saalim]

@pytorchbot label "release notes: none"

[meta-cla]

Thank you for signing our Contributor License Agreement. We can now accept your code for this (and any) Meta Open Source project. Thanks!

[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated no new comments.

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[mohammed-saalim]

is there any update? @manuelcandales @metascroy

[metascroy]

Looks great! Let's see what CI says

[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated no new comments.

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[mohammed-saalim]

I fixed the linting issue @metascroy
Lemme know if something needs to be changed.

[metascroy]

rerunning CI

[mohammed-saalim]

can u pls re-run it. @metascroy
Thanks!

[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated no new comments.

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[mohammed-saalim]

Hi @metascroy,

The linting issues have been resolved with the latest commits:

• Fixed trailing newline
• Fixed UFMT formatting

The failing Samsung test jobs (test-samsung-models-linux and test-samsung-quantmodels-linux) are due to a missing SAMSUNG_AI_LITECORE_KEY secret in the CI configuration, which is unrelated to this PR.

The CoreML-related changes and tests are ready for review. Thanks!

[metascroy]

Looks great! Just running some trunk jobs, and then I'll merge.

Thanks for the contribution!