fix: use npm run re:format with git diff check

[dikjain]

Type of Change

• Bugfix
• New feature
• Enhancement
• Refactoring
• Dependency updates
• Documentation
• CI/CD

Description

Added a ReScript formatter check to the CI/CD pipeline to ensure consistent code formatting across the codebase.

Changes made:

• Created .github/workflows/formatter-check.yml workflow file
• Workflow runs on every pull request and push to main branch
• Executes npm run re:format to format files
• Uses git diff to verify no formatting changes are needed
• Provides clear error messages indicating which files need formatting

Motivation and Context

This change addresses issue #3559.

Problem:
Currently, the project does not have an automated check in the CI/CD pipeline to ensure that code is formatted with the ReScript formatter. This leads to:

• Inconsistent code style across the codebase
• Increased code review effort on formatting issues
• Manual formatting checks by reviewers

Solution:
By integrating a formatter check into the pipeline, we can automatically verify formatting during pull requests and enforce consistency across the project.

How it works:

1. Runs npm run re:format in the CI environment
2. Checks if any files were modified by the formatter using git status --porcelain
3. If files were modified → formatting was incorrect → CI fails ❌
4. If no files were modified → formatting was correct → CI passes ✅

Closes #3559

How did you test it?

Testing performed:

• Verified the workflow file syntax is valid
• Tested formatter command locally: npm run re:format
• Tested formatter check command locally: npx rescript format -all -check
• Workflow will be automatically tested when this PR is created (CI will run)

Expected CI behavior:

• ✅ CI should pass if all files are properly formatted
• ❌ CI should fail if any files need formatting (with clear error messages)

Where to test it?

• GitHub Actions (automatically runs on PR)
• INTEG
• SANDBOX
• PROD

Checklist

• I ran npm run re:build
• I reviewed submitted code
• I added unit tests for my changes where possible (N/A - this is a CI/CD workflow)

Additional Notes

For Developers:
To check formatting locally before pushing:

# Check if files are formatted (doesn't modify)
npx rescript format -all -check

# Format files (modifies files)
npm run re:format

The CI check will ensure all ReScript files (.res and .resi) are properly formatted according to ReScript's standard formatting rules.

[semanticdiff-com]

Review changes with  

Changed Files

File	Status
.github/workflows/formatter-check.yml	0% smaller

[dikjain]

hey @JeevaRamu0104 , i've fixed this isse, can you please review it ?

[susrithasabbini]

Should we add AUTO_RELEASE_PAT in github secrets @JeevaRamu0104 or else default token will be generated by github actions each time it runs the workflow i guess.