fix: resolve hoisted tsc binaries

[mrousavy]

Summary

Resolve the TypeScript compiler binary by walking up ancestor node_modules/.bin directories before falling back to PATH.

This fixes package builds in workspaces where package dependencies are hoisted to the repository root, such as Bun workspaces. Previously Bob only checked <package>/node_modules/.bin/tsc, so a package with hoisted TypeScript could fail even though typescript was installed in the workspace.

Validation

• PATH="/Users/mrousavy/.nvm/versions/node/v24.16.0/bin:/opt/homebrew/bin:/opt/homebrew/sbin:/usr/local/bin:/System/Cryptexes/App/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin:/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/local/bin:/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/bin:/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/appleinternal/bin:/opt/pmk/env/global/bin:/Library/Apple/usr/bin:/Users/mrousavy/.codex/tmp/arg0/codex-arg0piPym5:/opt/homebrew/opt/binutils/bin:/Users/mrousavy/.nvm/versions/node/v20.19.4/bin:/Users/mrousavy/.rbenv/shims:/opt/homebrew/opt/openjdk@17/bin:/Users/mrousavy/Library/Android/sdk/emulator:/Users/mrousavy/Library/Android/sdk/tools:/Users/mrousavy/Library/Android/sdk/tools/bin:/Users/mrousavy/Library/Android/sdk/platform-tools:/Applications/Codex.app/Contents/Resources" yarn workspace react-native-builder-bob test run
• PATH="/Users/mrousavy/.nvm/versions/node/v24.16.0/bin:/opt/homebrew/bin:/opt/homebrew/sbin:/usr/local/bin:/System/Cryptexes/App/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin:/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/local/bin:/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/bin:/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/appleinternal/bin:/opt/pmk/env/global/bin:/Library/Apple/usr/bin:/Users/mrousavy/.codex/tmp/arg0/codex-arg0piPym5:/opt/homebrew/opt/binutils/bin:/Users/mrousavy/.nvm/versions/node/v20.19.4/bin:/Users/mrousavy/.rbenv/shims:/opt/homebrew/opt/openjdk@17/bin:/Users/mrousavy/Library/Android/sdk/emulator:/Users/mrousavy/Library/Android/sdk/tools:/Users/mrousavy/Library/Android/sdk/tools/bin:/Users/mrousavy/Library/Android/sdk/platform-tools:/Applications/Codex.app/Contents/Resources" yarn typecheck
• PATH="/Users/mrousavy/.nvm/versions/node/v24.16.0/bin:/opt/homebrew/bin:/opt/homebrew/sbin:/usr/local/bin:/System/Cryptexes/App/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin:/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/local/bin:/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/bin:/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/appleinternal/bin:/opt/pmk/env/global/bin:/Library/Apple/usr/bin:/Users/mrousavy/.codex/tmp/arg0/codex-arg0piPym5:/opt/homebrew/opt/binutils/bin:/Users/mrousavy/.nvm/versions/node/v20.19.4/bin:/Users/mrousavy/.rbenv/shims:/opt/homebrew/opt/openjdk@17/bin:/Users/mrousavy/Library/Android/sdk/emulator:/Users/mrousavy/Library/Android/sdk/tools:/Users/mrousavy/Library/Android/sdk/tools/bin:/Users/mrousavy/Library/Android/sdk/platform-tools:/Applications/Codex.app/Contents/Resources" yarn lint

[satya164]

Thanks for the PR

Few concerns:

• it'd be good to limit how much we traverse up, e.g., by checking the presence of a known lockfile to identify monorepo root
  • otherwise it may traverse up till ~/node_modules/.bin - which would be unexpected, especially because the warning isn't printed with such lookup
• iirc most package managers add binaries to PATH
  • I'm curious why it's not getting picked up by which. it may be because typescript isn't specified in the library's devDependencies
  • in case it's not in the immediate node_modules/.bin and the package manager is adding it to PATH, the latter would be a more appropriate pick

I think the appropriate workflow is to add typescript to devDependencies of the package in your project, but we can add manual lookup as well, given:

• lookup is bound to monorepo root (or we have a warning similar to the current which warning if it's found outside monorepo root)
• optionally prioritize PATH over node_modules/.bin lookup (package manager knows better than manual lookup)
• in both cases, we can identify monorepo root with the lockfile approach, and print a warning if the found path was outside so we have proper warning about incorrect setups
• for tests, let's move it to __tests__ folder and use mock-fs (which is already present) if possible