TypeScript compilation fails in azure-rest-api-specs pipelines

[mikeharder]

The following code was recently added to the root package.json in https://github.com/azure/azure-rest-api-specs:

  "scripts": {
    "postinstall": "tsc"
  },

https://github.com/Azure/azure-rest-api-specs/pull/23763/files#diff-7ae45ad102eab3b6d7e7896acd08c427a9b25b346470d7bc6507b6481575d519R21

This was added to improve the experience on dev machines, by compiling the scripts in the repo after running npm install.

However, this causes failures in the unified pipeline:

stdout: 
> postinstall
> tsc

../../../scripts/repo-sync/common.ts(2,21): error TS7016: Could not find a declaration file for module 'nodegit'. '/mnt/vss/_work/1/a/unified-pipeline-runtime/common/temp/node_modules/.pnpm/[email protected][email protected]/node_modules/nodegit/lib/nodegit.js' implicitly has an 'any' type.
  Try `npm i --save-dev @types/nodegit` if it exists or add a new declaration (.d.ts) file containing `declare module 'nodegit';`

https://dev.azure.com/azure-sdk/internal/_build/results?buildId=2753855&view=logs&j=e37a1bb9-a190-5269-3a0e-37469dfbe682&t=09cb0672-20c5-5dce-4552-dad3f3e96fd3

The failure is caused by the scripts/repo-sync folder in the openapi-alps repo unable to be successfully compiled, at least using the version of TypeScript in the azure-rest-api-specs repo.

As a temporary fix, I have removed the postinstall: tsc lines in Azure/azure-rest-api-specs#23837.

Better long-term fixes:

• Align the TypeScript versions and ensure the code from openapi-alps compiles when copied into azure-rest-api-specs
• Reduce the set of folders compiled in the preinstall script, to only those needed for local dev machine work