build: load every compiled schematic before publishing

The load failure fixed in the previous commit reached a published release
because nothing in the build or the test suite ever loads what actually ships.
The jasmine suite runs against the TypeScript output, which is a different
module format from the CommonJS bundle in the package, so a bundle can be
completely unloadable while every test passes.

Requiring each compiled entry point at the end of the schematics build closes
that gap. Reverting the previous commit now fails the build with the real
error:

    Compiled schematics failed to load:
      deploy/actions.js: TypeError [ERR_INVALID_ARG_TYPE] ...
      deploy/builder.js: TypeError [ERR_INVALID_ARG_TYPE] ...

It catches the whole class, not just this instance: an unresolvable import, a
bad top-level require, or anything else that throws at module load.

Author: armando-navarro

tools/build.ts

@@ -357,6 +357,35 @@ async function compileSchematics() {
     copy(src('schematics', 'setup', 'schema.json'), dest('schematics', 'setup', 'schema.json')),
   ]);
   await replaceSchematicVersions();
+  await loadCompiledSchematics();
+}
+
+/**
+ * Loads every compiled schematic entry point, so a bundle that cannot even be required fails the
+ * build instead of shipping.
+ */
+async function loadCompiledSchematics() {
+  const entryPoints = [
+    join('update', 'index.js'),
+    join('deploy', 'actions.js'),
+    join('deploy', 'builder.js'),
+    join('add', 'index.js'),
+    join('setup', 'index.js'),
+    join('update', 'v7', 'index.js'),
+    join('update', 'v21', 'index.js'),
+  ];
+  const failures: string[] = [];
+  for (const entryPoint of entryPoints) {
+    const path = dest('schematics', entryPoint);
+    try {
+      require(path);
+    } catch (error) {
+      failures.push(`  ${entryPoint}: ${error}`);
+    }
+  }
+  if (failures.length) {
+    throw new Error(`Compiled schematics failed to load:\n${failures.join('\n')}`);
+  }
 }
 
 async function buildLibrary() {