[build] Fully retire the non-lcmtypes drake module

In the past, we allowed 'import drake...' to refer to Python libraries
inside the Drake source tree. With bzlmod this is no longer practical.
Prior commits already removed most uses; this commit finishes the job.
From now on, imports should say e.g., 'from common...', instead.

Note that lcmtypes like 'from drake import lcmt_geometry_data' still
retain the 'drake' package name.

BUILD.bazel

@@ -3,7 +3,7 @@
 
 load("//tools/install:install.bzl", "install", "install_test")
 load("//tools/lint:lint.bzl", "add_lint_tests")
-load("//tools/skylark:py.bzl", "py_library")
+load("//tools/skylark:drake_py.bzl", "drake_py_library")
 
 package(
     default_visibility = ["//visibility:public"],
@@ -17,12 +17,13 @@ exports_files([
     "package.xml",
 ])
 
-# Drake's top-level module; all drake_py_stuff rules add this to deps.
-# (We use py_library here because drake_py_library would be circular.)
-# This file should NOT be installed (see commits in __init__.py).
-py_library(
+# A legacy hack module to disambiguate the 'drake' module when Drake is being
+# used as a non-bzlmod external. We should remove this when we drop support for
+# WORKSPACE (i.e., Bazel >= 9).
+drake_py_library(
     name = "module_py",
     srcs = ["__init__.py"],
+    visibility = ["//lcmtypes:__pkg__"],
 )
 
 # Expose shared library for (a) installed binaries, (b) Drake Python bindings,

__init__.py

@@ -1,17 +1,13 @@
-# It confusing to have both drake-the-workspace and drake-the-lcmtypes-package
-# on sys.path at the same time via Bazel's py_library(imports = ...).
+# It brittle to have both drake-the-workspace and drake-the-lcmtypes-package
+# available on the sys.path at the same time in Bazel.
 #
-# To prevent that confusion, and possibly also import errors, in our
-# //lcmtypes:lcmtypes_drake_py rule we use add_current_package_to_imports =
-# False, and then here in drake-the-workspace's package initialization we use
-# __path__ editing to fold the two directories into the same package.
+# To avoid import errors based on which one came first on the path, in our
+# //lcmtypes:lcmtypes_drake_py rule we depend on this file, and here (in
+# drake-the-workspace's package initialization) we use __path__ editing to
+# fold the two directories into the same package.
 #
 # We need to do it on a best-effort basis, because not all of our py_binary
 # rules use lcmtypes -- sometimes the lcmtypes will be absent from runfiles.
-#
-# Note that this file should NOT be installed (`//:install` should not touch
-# it).  The `//lcmtypes`-supplied init file is the correct file to install.
-
 try:
     import drake.lcmtypes
     __path__.append(list(drake.lcmtypes.__path__)[0] + "/drake")

bindings/pydrake/BUILD.bazel

@@ -35,6 +35,7 @@ exports_files([
 PACKAGE_INFO = get_pybind_package_info(base_package = "//bindings")
 
 # This target provides the following Python modules:
+# - drake (i.e., our lcmtypes)
 # - pydrake
 # - pydrake.autodiffutils
 # - pydrake.common (and all of its sub-modules)
@@ -48,6 +49,7 @@ drake_py_library(
     ],
     deps = [
         "//bindings/pydrake/common:_init_py",
+        "//lcmtypes:lcmtypes_drake_py",
     ],
 )
 
@@ -349,7 +351,6 @@ drake_py_unittest(
     name = "lcm_test",
     deps = [
         ":lcm_py",
-        "//lcmtypes:lcmtypes_drake_py",
     ],
 )
 

bindings/pydrake/systems/BUILD.bazel

@@ -227,7 +227,6 @@ drake_pybind_library(
         ":framework_py",
         ":module_py",
         "//bindings/pydrake:lcm_py",
-        "//lcmtypes:lcmtypes_drake_py",
     ],
     py_srcs = ["_lcm_extra.py"],
 )

bindings/pydrake/visualization/BUILD.bazel

@@ -49,7 +49,6 @@ drake_pybind_library(
         "//bindings/pydrake/systems",
         "//bindings/pydrake/geometry",
         "//bindings/pydrake:lcm_py",
-        "//lcmtypes:lcmtypes_drake_py",
     ],
     py_srcs = [
         "meldis.py",

common/proto/call_python_client_notebook.ipynb

@@ -18,7 +18,7 @@
    "outputs": [],
    "source": [
     "# Example Python client.\n",
-    "from drake.common.proto.call_python_client import CallPythonClient"
+    "from common.proto.call_python_client import CallPythonClient"
    ]
   },
   {

lcmtypes/BUILD.bazel

@@ -254,23 +254,12 @@ drake_lcm_cc_library(
     ],
 )
 
-# Generate the *.py sources, but keep __init__.py separate, so that it doesn't
-# get installed.  The install will use this (private) library.  Users should
-# depend on ":lcmtypes_drake_py", immediately below.
 drake_lcm_py_library(
-    name = "_generated_lcmtypes_drake_py",
-    # We'll rely on the //:module_py path munging instead.
-    add_current_package_to_imports = False,
+    name = "lcmtypes_drake_py",
     lcm_package = "drake",
     lcm_srcs = ALL_LCM_SRCS,
-    visibility = ["//visibility:private"],
-)
-
-drake_py_library(
-    name = "lcmtypes_drake_py",
-    srcs = ["__init__.py"],
     deps = [
-        ":_generated_lcmtypes_drake_py",
+        "//:module_py",
     ],
 )
 
@@ -351,7 +340,7 @@ install(
         ],
     }),
     targets = [
-        ":_generated_lcmtypes_drake_py",
+        ":lcmtypes_drake_py",
     ] + select({
         "@lcm//:lcm_install_java_is_off": [],
         "//conditions:default": [

multibody/parsing/test/package_downloader_test.py

@@ -8,7 +8,7 @@
 import unittest
 from urllib.error import HTTPError
 
-import drake.multibody.parsing.package_downloader as mut
+import multibody.parsing.package_downloader as mut
 
 # We'll mock out the internet-touching methods. We don't want our unit test
 # touching the internet. See setUp and tearDown below for details.

tools/skylark/drake_py.bzl

@@ -9,15 +9,10 @@ load("//tools/skylark:py.bzl", "py_binary", "py_library", "py_test")
 
 def drake_py_library(
         name,
-        deps = None,
         **kwargs):
     """A wrapper to insert Drake-specific customizations."""
-
-    # Work around https://github.com/bazelbuild/bazel/issues/1567.
-    deps = (deps or []) + ["//:module_py"]
     py_library(
         name = name,
-        deps = deps,
         srcs_version = "PY3",
         **kwargs
     )
@@ -134,11 +129,6 @@ def drake_py_binary(
         library code. This prevents submodules from leaking in as top-level
         submodules. For more detail, see #8041.
     """
-
-    # Work around https://github.com/bazelbuild/bazel/issues/1567.
-    deps = deps or []
-    if "//:module_py" not in deps:
-        deps += ["//:module_py"]
     if main == None and len(srcs) == 1:
         main = srcs[0]
     _py_target_isolated(
@@ -265,10 +255,7 @@ def drake_py_test(
     kwargs = incorporate_num_threads(kwargs, num_threads = num_threads)
     kwargs = amend(kwargs, "tags", append = ["py"])
 
-    # Work around https://github.com/bazelbuild/bazel/issues/1567.
     deps = deps or []
-    if "//:module_py" not in deps:
-        deps += ["//:module_py"]
     if not allow_import_unittest:
         deps = deps + ["//common/test_utilities:disable_python_unittest"]
     _py_target_isolated(