[drake_bazel_external] Port to use MODULE.bazel (#348)

drake_bazel_external/.bazelrc

@@ -1,9 +1,5 @@
 # SPDX-License-Identifier: MIT-0
 
-# Don't use bzlmod yet.
-common --enable_workspace=true
-common --enable_bzlmod=false
-
 # Default to an optimized build.
 build --compilation_mode=opt
 

drake_bazel_external/.gitignore

@@ -2,3 +2,4 @@
 
 /bazel-*
 /user.bazelrc
+/MODULE.bazel.lock

drake_bazel_external/MODULE.bazel

@@ -0,0 +1,58 @@
+# SPDX-License-Identifier: MIT-0
+
+module(name = "drake_external_examples")
+
+# If you don't want to support building on macOS, you may remove the next line.
+# Note that it must appear prior to loading "rules_cc", per the documentation:
+#  https://github.com/bazelbuild/apple_support?tab=readme-ov-file#bazel-7-setup
+bazel_dep(name = "apple_support", version = "1.17.1")
+
+# Add the Bazel rules we need.
+bazel_dep(name = "rules_cc", version = "0.0.17")
+bazel_dep(name = "rules_python", version = "0.40.0")
+
+# Here we introduce Drake as a module dependency, but note that Drake is not
+# published to any Bazel registry. Below, we'll override it with a github
+# source archive.
+bazel_dep(name = "drake")
+
+# By default, this example always uses the latest Drake master branch.
+DRAKE_COMMIT = "master"
+DRAKE_CHECKSUM = None
+
+# You can choose a specific revision of Drake to use, e.g.:
+# DRAKE_COMMIT = "19bb4703fdf4950d4b3530d496d8a0ff1ca5fc22"
+# DRAKE_CHECKSUM = "489d255db3cb1c8ff7a91ae0f961d76b6083a1d4a3f58150371b4b359683adb6"
+#
+# You can also use DRAKE_COMMIT to choose a Drake release; e.g.:
+# DRAKE_COMMIT = "v0.15.0"
+# DRAKE_CHECKSUM = "... TBD ..."
+#
+# Before changing the COMMIT, temporarily uncomment the next line so that Bazel
+# displays the suggested new value for the CHECKSUM.
+# DRAKE_CHECKSUM = "0" * 64
+
+# This declares the `@drake` module as a source code archive from github.
+# See README.md for instructions to use a local path, instead.
+archive_override(
+    module_name = "drake",
+    urls = [x.format(DRAKE_COMMIT) for x in [
+        "https://github.com/RobotLocomotion/drake/archive/{}.tar.gz",
+    ]],
+    sha256 = DRAKE_CHECKSUM,
+    strip_prefix = "drake-{}".format(DRAKE_COMMIT.lstrip("v")),
+)
+
+# Use the host system /usr/bin/python3.
+python_repository = use_repo_rule(
+    "@drake//tools/workspace/python:repository.bzl",
+    "python_repository",
+)
+
+python_repository(
+    name = "python",
+    linux_interpreter_path = "/usr/bin/python3",
+    requirements_flavor = "build",
+)
+
+register_toolchains("@python//:all")

drake_bazel_external/README.md

@@ -33,6 +33,15 @@ cause differences.  This is important when using tools like
 `drake::FindResource` / `pydrake.common.FindResource`.
 You may generally want to stick to using `bazel run` when able.
 
+### Using a local checkout of Drake
+
+To use Drake sources on disk instead of downloaded from github, pass the flag
+``--override_module=drake=/home/user/stuff/drake`` to bazel on the command line
+or add a line such as the following to ``user.bazelrc`` in the current directory:
+```
+build --override_module=drake=/home/user/stuff/drake
+```
+
 ## Python Versions
 
 By default, Python 3 is the Python interpreter that Drake will use when built

private/test/file_sync_test.py

@@ -62,16 +62,13 @@
     for path in [
         ".bazelignore",
         ".bazelproject",
-        ".bazelrc",
         ".clang-format",
         ".github/ci_build_test",
         ".github/setup",
         ".github/ubuntu_setup",
-        ".gitignore",
         "BUILD.bazel",
         "CPPLINT.cfg",
         "LICENSE",
-        "WORKSPACE",
         "apps/BUILD.bazel",
         "apps/exec.sh",
         "apps/find_resource_test.py",
@@ -84,7 +81,6 @@
         "apps/simple_adder_test.cc",
         "apps/simple_continuous_time_system.cc",
         "apps/simple_logging_example.py",
-        "environ.bzl",
         "setup/install_prereqs",
     ]
 ])