platform arch refactor

In working on #237 getting arm logic added in will take some interface redesign:

The existing Dependency interface is as such:

dependencies.ts

export interface Dependency {
  name: string;
  version: string;
  "darwin"?: PlatformDependency;
  "linux"?: PlatformDependency;
  "windows": PlatformDependency;
}

which is used by say the esBuild (and dart/pandoc) resolvers:

return {
    name: "esbuild javscript bundler",
    version,
    "windows": esBuildRelease("windows-64"),
    "linux": esBuildRelease("linux-64"),
    "darwin": esBuildRelease("darwin-64"),
  };

these then are used in configure.ts as kDependencies

// Download dependencies
  info("Downloading dependencies");
  for (const dependency of kDependencies) {
    info(`Preparing ${dependency.name}`);
    const platformDep = dependency[Deno.build.os];
    if (platformDep) {
      info(`Downloading ${dependency.name}`);
      const targetFile = await downloadBinaryDependency(platformDep, config);

      info(`Configuring ${dependency.name}`);
      await platformDep.configure(targetFile);

      info(`Cleaning up`);
      Deno.removeSync(targetFile);
    }
    info(`${dependency.name} complete.\n`);
  }

APIs to consider:

nested archs - Deno.build.arch can be "x86_64" | "aarch64" making it easy to use as a key

export interface Dependency {
  name: string;
  version: string;
  "aarch64": {
	  "darwin"?: PlatformDependency;
	  "linux"?: PlatformDependency;
	  "windows"?: PlatformDependency;
  };
  "x86_64": {
	  "darwin"?: PlatformDependency;
	  "linux"?: PlatformDependency;
	  "windows"?: PlatformDependency;
  };
}

which would essentially result in dl resolution code changing to:

-const platformDep = dependency[Deno.build.os];
+const platformDep = dependency[Deno.build.arch][Deno.build.os];

or some flatter designs:

• x86 default:
  • darwin + darwin-aarch64
• no default (my preference given a flat structure):
  • darwin-x86_64 + darwin-x86_64

and do something like

-const platformDep = dependency[Deno.build.os];
+const platformDep = dependency[`${Deno.build.os}-${Deno.build.arch}`];

Secondarily, the other implication to consider in the surrounding code is that arm builds are still generally not as first-class. While it seems everything has x86 builds in place, even for misc dev versions, arm versions are more hit or miss. As such, the general codebase could potentially use a little love to make more informative where its hitting problems and potentially more aggressively halt. The existing code just tries to dl if it exists and regardless will print info(${dependency.name} complete.\n);

@dragonstyle any particular preferences or other interface designs come to mind?

Start with dependencies.ts and configure.ts, including the kDependencies loop and its use of Deno.build.os; review the existing resolver examples for esBuild, dart, and pandoc. Done means the project has a settled interface for OS and architecture selection and dependency setup reports missing or unsuccessful downloads instead of unconditionally printing completion.