If running hook/build.dart of a package fails, then we should not continue building dependent packages

[mkustermann]

It seems currently the build runner will make a plan (order of packages) and then build all of them. See here

  Future<HookResult> _run({}) async {
    ...
    final (buildPlan, packageGraph, planSuccess) = await _makePlan(...);
    ...
    for (final package in buildPlan) {
    ...
    final (hookOutput, packageSuccess) = await _runHookForPackageCached(...);
    final validateResult = validateNoDuplicateDylibs(hookResult.assets);
    if (validateResult.isNotEmpty) {
      for (final error in validateResult) {
        logger.severe(error);
      }
      hookResult = hookResult.copyAdd(HookOutputImpl(), false);
    }

    return hookResult;
  }

I don't see any path where it fails early, which seems problematic: If package:foo depends on package:bar, both of them have build hooks and foos hook depends on outputs from bars hook, then if bar fails to build, we shouldn't even attempt to build foo.

Conservatively it could fail after the first package that failed to build or verify correctly.

Slightly better would be to have a graph (or more precisely a DAG) and build everything whose dependencies have transitively been successfully built, but never attempt to build a package that has any transitive dependencies with build failures.