feat(packages): POC — migrate to Bun + Nx for faster incremental package/plugin builds

[rusackas]

SUMMARY

Note

Bycatch warning: I was annoyed by the lack of license headers, so I added a pre-commit hook to catch that for changed/new files. On CI, that runs on EVERYTHING, and it caught some old files without headers! So you'll see those updates here as well.

This PR updates Superset's frontend build system by combining Bun's fast JavaScript runtime with Nx's intelligent caching, achieving dramatic performance improvements:

• Faster full builds I forget the benchmarks, but it was about 30% faster or so
• 68x faster incremental builds (56s → 0.8s when no changes)
• 10-20x faster typical builds (only rebuild what changed)
• Fixed TypeScript error reporting that was silently failing
• DRY configuration - reduced 325+ lines of repetitive config
• Local caching only - no cloud dependencies

Key Changes

1. Nx Build Caching: Intelligent, dependency-aware caching that only rebuilds changed packages
2. Bun-Optimized Pipeline: Parallel Babel compilation with better CPU utilization (470%+ vs 350%)
3. Fixed tsc.sh Bug: TypeScript errors now properly reported (was silently ignoring errors)
4. Apache License Compliance: Added pre-commit hooks for license header checking
5. DRY Configuration: Moved repetitive config to nx.json, reducing each project.json from 20 to 7 lines

BEFORE/AFTER SCREENSHOTS OR ANIMATED GIF

Before: Every build takes 56s regardless of changes

$ npm run plugins:build
... 56 seconds later ...

After: Incremental builds with caching

$ npm run plugins:build
✔  25/25 tasks [25 read from cache]
... 0.8 seconds ...

Performance benchmarks:

Scenario	Old (npm)	New (Bun+Nx)	Improvement
No changes	56s	0.8s	68x faster
1 package changed	56s	~3s	18x faster
5 packages changed	56s	~12s	4.6x faster

TESTING INSTRUCTIONS

1. Test the build system:

   # Clean install and initial build
   npm ci
   npm run plugins:build  # First build: ~56s (populating cache)
   
   # Test cache hit
   npm run plugins:build  # Second build: ~0.8s (100% cache hits)
   
   # Test incremental build
   echo "// test" >> superset-frontend/plugins/plugin-chart-table/src/index.ts
   npm run plugins:build  # Only rebuilds plugin-chart-table and dependents

2. Verify TypeScript error reporting:

   # Add a type error to any package
   echo "const x: string = 123;" >> superset-frontend/packages/superset-ui-core/src/index.ts
   npm run plugins:build  # Should fail with TypeScript error
   git restore superset-frontend/packages/superset-ui-core/src/index.ts

3. Test license compliance:

   # Create a file without license header
   echo "console.log('test');" > test.js
   git add test.js
   git commit -m "test"  # Pre-commit hook should fail
   rm test.js

ADDITIONAL INFORMATION

• Has associated issue:
• Required feature flags:
• Changes UI
• Includes DB Migration (follow approval process in SIP-59)
  • Migration is atomic, supports rollback & is backwards-compatible
  • Confirm DB migration upgrade and downgrade tested
  • Runtime estimates and downtime expectations provided
• Introduces new feature or API (Nx build caching)
• Removes existing feature or API

Notes:

• No breaking changes - npm run plugins:build works exactly the same, just faster
• All build outputs are identical to the previous system
• Pre-commit hooks automatically installed on npm install
• Local caching only (no Nx Cloud), stored in .nx/cache

[korbit-ai]

Based on your review schedule, I'll hold off on reviewing this PR until it's marked as ready for review. If you'd like me to take a look now, comment /korbit-review.

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