Add '--bail' option when running '--build' mode

Search Terms

project references, bail, cascade, errors

Suggestion

When building multiple Typescript projects using the --build flag, and the projects had dependencies on each other, an error in an upstream project can cause a cascade of errors from downstream projects that obscure the original error.

A possible solution would be a --bail option (or however you'd like to name it). When provided in --build mode, it would prevent all projects downstream from a project with an error from building. While this may hide downstream errors that are only found when re-running, it will prevent "false-positive" errors from being shown.

Use Cases

Using --build mode on a large web of project references, without the possibility of being flooded with spurious errors due to one upstream typo.

Checklist

My suggestion meets these guidelines:

• This wouldn't be a breaking change in existing TypeScript/JavaScript code
• This wouldn't change the runtime behavior of existing JavaScript code
• This could be implemented without emitting different JS based on the types of the expressions
• This isn't a runtime feature (e.g. library functionality, non-ECMAScript syntax with JavaScript output, etc.)
• This feature would agree with the rest of TypeScript's Design Goals.

Start at the TypeScript command-line handling for --build and trace how project references are built in dependency order. Reproduce the cascade with multiple referenced projects and an upstream error, then determine how a --bail option should stop downstream builds. Done means the option works in --build mode without changing existing behavior when it is absent.