build(bazel): Emit metadata.json under Blaze

packages/bazel/src/ng_module.bzl

@@ -22,6 +22,11 @@ def _basename_of(ctx, file):
     ext_len = len(".html")
   return file.short_path[len(ctx.label.package) + 1:-ext_len]
 
+# Return true if run with bazel (the open-sourced version of blaze), false if
+# run with blaze.
+def _is_bazel():
+  return not hasattr(native, "genmpm")
+
 def _flat_module_out_file(ctx):
   """Provide a default for the flat_module_out_file attribute.
 
@@ -50,8 +55,7 @@ def _should_produce_flat_module_outs(ctx):
   Returns:
     true iff we should run the bundle_index_host to produce flat module metadata and bundle index
   """
-  is_bazel = not hasattr(native, "genmpm")
-  return is_bazel and ctx.attr.module_name
+  return _is_bazel() and ctx.attr.module_name
 
 # Calculate the expected output of the template compiler for every source in
 # in the library. Most of these will be produced as empty files but it is
@@ -81,28 +85,32 @@ def _expected_outs(ctx):
             ".js",
         ]
         summaries = [".ngsummary.json"]
+        metadata = [".metadata.json"]
       else:
         devmode_js = [".js"]
         summaries = []
+        metadata = []
     elif short_path.endswith(".css"):
       basename = short_path[len(package_prefix):-len(".css")]
       devmode_js = [
           ".css.shim.ngstyle.js",
           ".css.ngstyle.js",
       ]
       summaries = []
-
+      metadata = []
     else:
       continue
 
     filter_summaries = ctx.attr.filter_summaries
     closure_js = [f.replace(".js", ".closure.js") for f in devmode_js if not filter_summaries or not f.endswith(".ngsummary.js")]
     declarations = [f.replace(".js", ".d.ts") for f in devmode_js]
 
-    devmode_js_files += [ctx.new_file(ctx.bin_dir, basename + ext) for ext in devmode_js]
-    closure_js_files += [ctx.new_file(ctx.bin_dir, basename + ext) for ext in closure_js]
-    declaration_files += [ctx.new_file(ctx.bin_dir, basename + ext) for ext in declarations]
-    summary_files += [ctx.new_file(ctx.bin_dir, basename + ext) for ext in summaries]
+    devmode_js_files  += [ctx.actions.declare_file(basename + ext) for ext in devmode_js]
+    closure_js_files  += [ctx.actions.declare_file(basename + ext) for ext in closure_js]
+    declaration_files += [ctx.actions.declare_file(basename + ext) for ext in declarations]
+    summary_files     += [ctx.actions.declare_file(basename + ext) for ext in summaries]
+    if not _is_bazel():
+      metadata_files  += [ctx.actions.declare_file(basename + ext) for ext in metadata]
 
   # We do this just when producing a flat module index for a publishable ng_module
   if _should_produce_flat_module_outs(ctx):
@@ -330,7 +338,8 @@ def ng_module_impl(ctx, ts_compile_actions, ivy = False):
 
   outs = _expected_outs(ctx)
   providers["angular"] = {
-    "summaries": outs.summaries
+    "summaries": outs.summaries,
+    "metadata": outs.metadata
   }
   providers["ngc_messages"] = outs.i18n_messages
 

packages/bazel/src/ngc-wrapped/index.ts

@@ -268,6 +268,12 @@ export function compile({allowNonHermeticReads, allDepsCompiledWithBazel = true,
     }
   }
 
+  if (!bazelOpts.nodeModulesPrefix) {
+    // If there is no node modules, then metadata.json should be emitted since
+    // there is no other way to obtain the information
+    generateMetadataJson(program.getTsProgram(), files, compilerOpts.rootDirs, bazelBin, tsHost);
+  }
+
   if (bazelOpts.tsickleExternsPath) {
     // Note: when tsickleExternsPath is provided, we always write a file as a
     // marker that compilation succeeded, even if it's empty (just containing an
@@ -282,6 +288,31 @@ export function compile({allowNonHermeticReads, allDepsCompiledWithBazel = true,
   return {program, diagnostics};
 }
 
+/**
+ * Generate metadata.json for the specified `files`. By default, metadata.json
+ * is only generated by the compiler if --flatModuleOutFile is specified. But
+ * if compiled under blaze, we want the metadata to be generated for each
+ * Angular component.
+ */
+function generateMetadataJson(
+    program: ts.Program, files: string[], rootDirs: string[], bazelBin: string,
+    tsHost: ts.CompilerHost) {
+  const collector = new ng.MetadataCollector();
+  for (const file of files) {
+    const sourceFile = program.getSourceFile(file);
+    if (sourceFile) {
+      const metadata = collector.getMetadata(sourceFile);
+      if (metadata) {
+        const relative = relativeToRootDirs(file, rootDirs);
+        const shortPath = relative.replace(EXT, '.metadata.json');
+        const outFile = resolveNormalizedPath(bazelBin, shortPath);
+        const data = JSON.stringify(metadata);
+        tsHost.writeFile(outFile, data, false, undefined, []);
+      }
+    }
+  }
+}
+
 function isCompilationTarget(bazelOpts: BazelOptions, sf: ts.SourceFile): boolean {
   return !NGC_GEN_FILES.test(sf.fileName) &&
       (bazelOpts.compilationTargetSrc.indexOf(sf.fileName) !== -1);