[build] Adjust new_release for bzlmod spellings

MODULE.bazel

@@ -258,6 +258,5 @@ use_repo(
 # - Provide better configuration options for choosing dependencies.
 # - Adjust the wheel build to build more dependencies as Bazel modules.
 # - Update the maintainer docs in tools/workspace/README.
-# - Debug any new glitches with the new_release automation.
 # - Investigate any impact on S3 mirroring.
 # - Deprecate non-bzlmod use of Drake downstream.

tools/workspace/metadata.bzl

@@ -5,10 +5,12 @@ def generate_repository_metadata(repository_ctx, **kwargs):
     dict entry of name="" using the repository_ctx.name.  This information can
     be loaded later using the tools/workspace/metadata.py library.
     """
+    canonical_name = repository_ctx.name
+    apparent_name = canonical_name.split("+")[-1]
     repository_ctx.file(
         "drake_repository_metadata.json",
         content = json.encode(struct(
-            name = repository_ctx.name,
+            name = apparent_name,
             **kwargs
         )),
         executable = False,

tools/workspace/metadata.py

@@ -5,10 +5,52 @@
 
 import glob
 import json
+import logging
 import os
 import subprocess
 
 
+_REPOSITORIES_WITH_NO_METADATA = [
+    # Bazel modules.
+    "eigen",
+    "fmt",
+    "spdlog",
+    "module_eigen",
+    "module_fmt",
+    "module_spdlog",
+    "pkgconfig_eigen",
+    "pkgconfig_fmt",
+    "pkgconfig_spdlog",
+    "platforms",
+    "rules_cc",
+    "rules_java",
+    "rules_license",
+    "rules_python",
+    "rules_rust",
+    "rules_shell",
+    # Host libraries / binaries.
+    "gfortran",
+    "glib",
+    "glx",
+    "gurobi",
+    "lapack",
+    "libblas",
+    "liblapack",
+    "mumps_internal",
+    "nasm",
+    "net_sf_jchart2d",
+    "opencl",
+    "opengl",
+    "org_apache_xmlgraphics_commons",
+    "x11",
+    "zlib",
+    # Vendored.
+    "doxygen",
+    "snopt",
+    "spgrid_internal",
+]
+
+
 def _check_output(args):
     return subprocess.check_output(args).decode("utf8")
 
@@ -31,9 +73,15 @@ def read_repository_metadata(repositories=None):
         repositories = set()
         for line in package_lines.split("\n"):
             if not line.startswith("@"):
+                # Not a repository.
                 continue
-            name = line[1:].split("/")[0]
-            repositories.add(name)
+            if line.startswith("@@"):
+                # A repository that only has a canonical name, not an apparent
+                # name. That means we don't load it in MODULE.bzl, so we don't
+                # care about its metadata.
+                continue
+            apparent_name = line[1:].split("/")[0]
+            repositories.add(apparent_name)
 
         # The bazel query only finds build-time dependencies.  Drake also
         # requires some load-time dependencies such as starlark libraries,
@@ -49,15 +97,28 @@ def read_repository_metadata(repositories=None):
     subprocess.check_call(["bazel", "fetch", "//..."])
 
     # Read the metadata.
-    for name in sorted(repositories):
-        json_path = os.path.join(
-            output_base, "external", name, "drake_repository_metadata.json")
-        try:
-            with open(json_path, "r") as f:
-                data = json.load(f)
-                result[data["name"]] = data
-        except IOError:
-            pass
+    for apparent_name in sorted(repositories):
+        found = False
+        for canonical_name in [
+                f"+drake_dep_repositories+{apparent_name}",
+                f"+internal_repositories+{apparent_name}"]:
+            json_path = os.path.join(
+                output_base, "external", canonical_name,
+                "drake_repository_metadata.json")
+            try:
+                with open(json_path, "r") as f:
+                    data = json.load(f)
+                    result[data["name"]] = data
+            except IOError:
+                pass
+            if found:
+                break
+
+    # Yell when something went wrong.
+    if not found and apparent_name not in _REPOSITORIES_WITH_NO_METADATA:
+        logging.warn(f"Missing metadata for {apparent_name}")
+    elif found and apparent_name in _REPOSITORIES_WITH_NO_METADATA:
+        logging.warn(f"Unexpectedly found metadata for {name}")
 
     # Add 'magic' metadata for repositories that don't/can't generate it the
     # usual way.