fabric: unify CLI with `jsonargparse` [wip] #21150

Borda · 2025-09-03T07:55:01Z

What does this PR do?

reduce dependencies and since pytorch is already based on jsonargparse, there is no need for click

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📚 Documentation preview 📚: https://pytorch-lightning--21150.org.readthedocs.build/en/21150/

github-actions · 2025-09-03T07:55:25Z

⛈️ Required checks status: Has failure 🔴

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Groups summary

🟢 pytorch_lightning: Tests workflow

Check ID	Status
pl-cpu-guardian	success	✅

These checks are required after the changes to requirements/fabric/test.txt, src/lightning/fabric/cli.py.

🟢 pytorch_lightning: Azure GPU

Check ID	Status
pytorch-lightning (GPUs) (testing Lightning \| latest)	success	✅
pytorch-lightning (GPUs) (testing PyTorch \| oldest)	success	✅
pytorch-lightning (GPUs) (testing PyTorch \| latest)	success	✅

These checks are required after the changes to requirements/fabric/test.txt, src/lightning/fabric/cli.py.

🔴 pytorch_lightning: Benchmarks

Check ID	Status
lightning.Benchmarks	failure	❌

These checks are required after the changes to requirements/fabric/test.txt, src/lightning/fabric/cli.py.

🟢 fabric: Docs

Check ID	Status
docs-make (fabric, doctest)	success	✅
docs-make (fabric, html)	success	✅

These checks are required after the changes to src/lightning/fabric/cli.py, requirements/fabric/test.txt.

🟢 pytorch_lightning: Docker

Check ID	Status
build-cuda (3.10, 2.1.2, 12.1.1)	success	✅
build-cuda (3.11, 2.2.2, 12.1.1)	success	✅
build-cuda (3.11, 2.3.1, 12.1.1)	success	✅
build-cuda (3.11, 2.4.1, 12.1.1)	success	✅
build-cuda (3.12, 2.5.1, 12.1.1)	success	✅
build-cuda (3.12, 2.6.0, 12.4.1)	success	✅
build-pl (3.10, 2.1, 12.1.1)	success	✅
build-pl (3.11, 2.2, 12.1.1)	success	✅
build-pl (3.11, 2.3, 12.1.1)	success	✅
build-pl (3.11, 2.4, 12.1.1)	success	✅
build-pl (3.12, 2.5, 12.1.1)	success	✅
build-pl (3.12, 2.6, 12.4.1)	success	✅
build-pl (3.12, 2.7, 12.6.3)	success	✅
build-pl (3.12, 2.8, 12.6.3, true)	success	✅

These checks are required after the changes to requirements/fabric/test.txt.

🔴 lightning_fabric: CPU workflow

Check ID	Status
fabric-cpu-guardian	failure	❌

These checks are required after the changes to requirements/fabric/test.txt, src/lightning/fabric/cli.py, tests/tests_fabric/test_cli.py.

🔴 lightning_fabric: Azure GPU

Check ID	Status
lightning-fabric (GPUs) (testing Fabric \| oldest)	failure	❌
lightning-fabric (GPUs) (testing Fabric \| latest)	failure	❌
lightning-fabric (GPUs) (testing Lightning \| latest)	success	✅

These checks are required after the changes to requirements/fabric/test.txt, src/lightning/fabric/cli.py, tests/tests_fabric/test_cli.py.

🟢 mypy

Check ID	Status
mypy	success	✅

These checks are required after the changes to requirements/fabric/test.txt, src/lightning/fabric/cli.py.

🟢 install

Check ID	Status
install-pkg-guardian	success	✅

These checks are required after the changes to src/lightning/fabric/cli.py, requirements/fabric/test.txt.

Thank you for your contribution! 💜

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Copilot

Pull Request Overview

This PR replaces the Click-based CLI implementation with jsonargparse, aligning with PyTorch's CLI approach while reducing dependencies. The change introduces a class-based CLI structure that provides the same functionality through jsonargparse's ArgumentParser.

Key changes:

Replace Click dependency with jsonargparse[signatures] for CLI argument parsing
Restructure CLI from function-based to class-based architecture using FabricCLI
Update test requirements to use jsonargparse instead of Click

Reviewed Changes

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

File	Description
src/lightning/fabric/cli.py	Complete rewrite from Click to jsonargparse with new `FabricCLI` class structure
requirements/fabric/test.txt	Replace Click dependency with jsonargparse[signatures] requirement

_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}

src/lightning/fabric/cli.py

Copilot · 2025-09-03T07:57:37Z

src/lightning/fabric/cli.py

+            "--output_file",
+            type=str,


The original Click validation type=click.Path(exists=True) for output_file has been removed, but output files should typically NOT exist (they're being created). The original validation logic appears incorrect and this change fixes it, but the help text still mentions 'The file should not already exist' without enforcement.

codecov · 2025-09-03T08:25:48Z

Codecov Report

❌ Patch coverage is 27.86885% with 44 lines in your changes missing coverage. Please review.
✅ Project coverage is 81%. Comparing base (04e103b) to head (3d64840).
⚠️ Report is 5 commits behind head on master.
✅ All tests successful. No failed tests found.

❗ There is a different number of reports uploaded between BASE (04e103b) and HEAD (3d64840). Click for more details.

HEAD has 108 uploads less than BASE

Flag BASE (04e103b) HEAD (3d64840)

cpu 54 27

python 6 3

lightning_fabric 14 2

pytest 30 3

lightning 31 16

python3.11 12 6

python3.12 6 3

python3.10 12 6

python3.12.7 18 9

Additional details and impacted files

@@            Coverage Diff            @@
##           master   #21150     +/-   ##
=========================================
- Coverage      87%      81%     -6%     
=========================================
  Files         269      269             
  Lines       23595    23627     +32     
=========================================
- Hits        20581    19127   -1454     
- Misses       3014     4500   +1486

for more information, see https://pre-commit.ci

…into fabric/cli

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Borda requested review from lantiga, tchaton, justusschock and ethanwharris as code owners September 3, 2025 07:55

github-actions bot added fabric lightning.fabric.Fabric dependencies Pull requests that update a dependency file labels Sep 3, 2025

Borda requested a review from Copilot September 3, 2025 07:55

Copilot AI reviewed Sep 3, 2025

View reviewed changes

Borda changed the title ~~fabric: unify CLI with jsonargparse~~ fabric: unify CLI with jsonargparse [wip] Sep 3, 2025

fabric: unify CLI with jsonargparse

9ac0601

Borda force-pushed the fabric/cli branch from 3d64840 to 9ac0601 Compare September 9, 2025 19:19

pre-commit-ci bot and others added 4 commits September 9, 2025 19:20

[pre-commit.ci] auto fixes from pre-commit.com hooks

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for more information, see https://pre-commit.ci

update tests

d90cef8

Merge branch 'fabric/cli' of https://github.com/Lightning-AI/lightning …

b6b89e4

…into fabric/cli

[pre-commit.ci] auto fixes from pre-commit.com hooks

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fabric: unify CLI with `jsonargparse` [wip] #21150

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fabric: unify CLI with `jsonargparse` [wip] #21150

fabric: unify CLI with `jsonargparse` [wip] #21150

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