[workspace] Deprecate lcm (in lieu of lcm_internal)

MODULE.bazel

@@ -151,18 +151,14 @@ use_repo(
     #
     "pybind11",
     #
-    # TODO(jwnimmer-tri) Move this to be internal (+ deprecation). However, it
-    # has bzlmod support so the rework will be a bit nuanced and attacked as a
-    # dedicated commit.
+    # Deprecated 2026-02-01.
     #
     "lcm",
 )
 
 # Load Java dependencies.
 
-# TODO(jwnimmer-tri) This is no longer used by Drake, but is kept around for
-# backwards compatibility for the to-be-deprecated `@lcm` external. It will be
-# deprecated for removal along with the entire @lcm repository soon enough.
+# TODO(jwnimmer-tri) Remove this during @lcm deprecation removal on 2026-02-01.
 maven = use_extension("@rules_jvm_external//:extensions.bzl", "maven")
 maven.install(
     name = "lcm_maven",

tools/workspace/lcm/BUILD.bazel

@@ -5,19 +5,17 @@ load(
     "drake_py_unittest",
 )
 
-# TODO(jwnimmer-tri) These tests are no longer relevant for Drake, but are kept
-# around as regression coverage of our `package.BUILD.bazel` file. This file
-# (and its tests) will be removed when the `@lcm` deprecation is removed.
+# Remove everything here on 2026-02-01 along with LCM deprecation.
 
 drake_py_test(
     name = "import_lcm_test",
     allow_import_unittest = True,
-    deps = ["@lcm//:lcm-python"],
+    deps = ["@lcm//:lcm-python_non_deprecated"],
 )
 
 drake_py_unittest(
     name = "no_lcm_warnings_test",
-    deps = ["@lcm//:lcm-python"],
+    deps = ["@lcm//:lcm-python_non_deprecated"],
 )
 
 add_lint_tests()

tools/workspace/lcm/example/BUILD.bazel

@@ -9,6 +9,9 @@ load(
     "lcm_py_library",
 )
 
+# Remove everything here on 2026-02-01 along with LCM deprecation.
+# This directory is a regression test for that deprecated external.
+
 package(default_visibility = ["//visibility:private"])
 
 _LCM_PACKAGE = "package1.package2"
@@ -23,6 +26,7 @@ lcm_cc_library(
     aggregate_hdr = "package1/package2/package2.hpp",
     lcm_package = _LCM_PACKAGE,
     lcm_srcs = _LCM_SRCS,
+    macro_deprecation = None,
     # Disable Drake's add_lint_tests() for this library.
     # This line would not typically be required for non-Drake projects.
     tags = ["nolint"],
@@ -32,6 +36,7 @@ lcm_java_library(
     name = "java_lib",
     lcm_package = _LCM_PACKAGE,
     lcm_srcs = _LCM_SRCS,
+    macro_deprecation = None,
     # Disable Drake's add_lint_tests() for this library.
     # This line would not typically be required for non-Drake projects.
     tags = ["nolint"],
@@ -41,6 +46,7 @@ lcm_py_library(
     name = "py_lib",
     lcm_package = _LCM_PACKAGE,
     lcm_srcs = _LCM_SRCS,
+    macro_deprecation = None,
     # Disable Drake's add_lint_tests() for this library.
     # This line would not typically be required for non-Drake projects.
     tags = ["nolint"],

tools/workspace/lcm/lcm.bzl

@@ -139,6 +139,8 @@ _lcm_library_gen = rule(
     implementation = _lcmgen_impl,
 )
 
+MACRO_DEPRECATION = "DRAKE DEPRECATED: The starlark macros at `@drake//tools/workspace/lcm:lcm.bzl` are deprecated for removal. Instead, you should add LCM to your project's MODULE.bazel file as a bazel module and then use LCM's upstream Bazel support at `@lcm//lcm-bazel:*.bzl`. The deprecated code will be removed from Drake on or after 2026-01-01."  # noqa
+
 def lcm_cc_library(
         name,
         lcm_srcs = [],
@@ -147,6 +149,7 @@ def lcm_cc_library(
         deprecation = None,
         aggregate_hdr = None,
         aggregate_hdr_strip_prefix = ["**/include/"],
+        macro_deprecation = MACRO_DEPRECATION,
         _use_new_lcm_gen = False,
         **kwargs):
     """Declares a cc_library on message classes generated from `*.lcm` files.
@@ -176,6 +179,8 @@ def lcm_cc_library(
         fail("lcm_srcs is required")
     if not lcm_package:
         fail("lcm_package is required")
+    if macro_deprecation != None:
+        print(macro_deprecation)
 
     helper_tags = []
     for sticky_tag in ["manual", "nolint"]:
@@ -201,11 +206,15 @@ def lcm_cc_library(
             tags = helper_tags,
         )
     else:
+        lcmgen = None
+        if macro_deprecation == None:
+            lcmgen = "@lcm//:lcm-gen_non_deprecated"
         _lcm_library_gen(
             name = name + "_lcm_library_gen",
             language = "cc",
             lcm_srcs = lcm_srcs,
             lcm_package = lcm_package,
+            lcmgen = lcmgen,
             outs = outs,
             deprecation = deprecation,
             tags = helper_tags,
@@ -226,7 +235,10 @@ def lcm_cc_library(
     deps = kwargs.pop("deps", [])
     if not _use_new_lcm_gen:
         if "@lcm//:lcm_coretypes" not in deps:
-            deps = deps + ["@lcm//:lcm_coretypes"]
+            if macro_deprecation == None:
+                deps = deps + ["@lcm//:lcm_coretypes_non_deprecated"]
+            else:
+                deps = deps + ["@lcm//:lcm_coretypes"]
 
     includes = kwargs.pop("includes", [])
     if "." not in includes:
@@ -252,6 +264,7 @@ def lcm_py_library(
         lcm_structs = [],
         add_current_package_to_imports = True,
         extra_srcs = [],
+        macro_deprecation = MACRO_DEPRECATION,
         **kwargs):
     """Declares a py_library on message classes generated from `*.lcm` files.
 
@@ -275,13 +288,19 @@ def lcm_py_library(
         fail("lcm_srcs is required")
     if not lcm_package:
         fail("lcm_package is required")
+    if macro_deprecation != None:
+        print(macro_deprecation)
 
     outs = _lcm_outs(lcm_srcs, lcm_package, lcm_structs, ".py")
+    lcmgen = None
+    if macro_deprecation == None:
+        lcmgen = "@lcm//:lcm-gen_non_deprecated"
     _lcm_library_gen(
         name = name + "_lcm_library_gen",
         language = "py",
         lcm_srcs = lcm_srcs,
         lcm_package = lcm_package,
+        lcmgen = lcmgen,
         outs = outs,
     )
 
@@ -300,6 +319,7 @@ def lcm_java_library(
         lcm_srcs = [],
         lcm_package = None,
         lcm_structs = [],
+        macro_deprecation = MACRO_DEPRECATION,
         **kwargs):
     """Declares a java_library on message classes generated from `*.lcm` files.
 
@@ -311,19 +331,28 @@ def lcm_java_library(
         fail("lcm_srcs is required")
     if not lcm_package:
         fail("lcm_package is required")
+    if macro_deprecation != None:
+        print(macro_deprecation)
 
     outs = _lcm_outs(lcm_srcs, lcm_package, lcm_structs, ".java")
+    lcmgen = None
+    if macro_deprecation == None:
+        lcmgen = "@lcm//:lcm-gen_non_deprecated"
     _lcm_library_gen(
         name = name + "_lcm_library_gen",
         language = "java",
         lcm_srcs = lcm_srcs,
         lcm_package = lcm_package,
+        lcmgen = lcmgen,
         outs = outs,
     )
 
     deps = kwargs.pop("deps", [])
     if "@lcm//:lcm-java" not in deps:
-        deps = deps + ["@lcm//:lcm-java"]
+        if macro_deprecation == None:
+            deps = deps + ["@lcm//:lcm-java_non_deprecated"]
+        else:
+            deps = deps + ["@lcm//:lcm-java"]
 
     java_library(
         name = name,

tools/workspace/lcm/package.BUILD.bazel

@@ -3,15 +3,14 @@
 load("@drake//tools/skylark:cc.bzl", "cc_binary", "cc_library")
 load("@drake//tools/skylark:java.bzl", "java_binary", "java_library")
 load("@drake//tools/skylark:py.bzl", "py_library")
+load("@drake//tools/skylark:sh.bzl", "sh_binary")
 load(
     "@drake//tools/workspace:generate_export_header.bzl",
     "generate_export_header",
 )
 load("@drake//tools/workspace:generate_file.bzl", "generate_file")
 
-# TODO(jwnimmer-tri) Nothing in this file is used by Drake anymore, but is kept
-# around for backwards compatibility. The @lcm repository will be deprecated for
-# removal soon.
+# Everything here is deprecated for removal on 2026-02-01.
 
 licenses([
     "notice",  # BSD-3-Clause
@@ -62,6 +61,8 @@ LCM_PUBLIC_HEADER_INCLUDES = [
     "lcm",
 ]
 
+DEPRECATION = "DRAKE DEPRECATED: The @lcm module extension from drake_dep_repositories() is deprecated for removal. Upstream LCM now has native bazel support; use the upstream BUILD rules, instead. The deprecated code will be removed from Drake on or after 2026-02-01."  # noqa
+
 # We only build a shared-library flavor of liblcm.so, because its LGPL-licensed
 # and thus should never be linked statically.  Building C++ shared libraries
 # in Bazel is not well-supported, but for C code is relatively trivial.  This
@@ -112,6 +113,7 @@ cc_library(
     srcs = ["libdrake_lcm.so"],
     hdrs = LCM_PUBLIC_HEADERS,
     includes = LCM_PUBLIC_HEADER_INCLUDES,
+    deprecation = DEPRECATION,
 )
 
 # This is the header-only library used by generated messages.
@@ -120,6 +122,7 @@ cc_library(
     hdrs = ["lcm/lcm_coretypes.h"],
     includes = ["."],
     linkstatic = True,
+    deprecation = DEPRECATION,
 )
 
 cc_binary(
@@ -134,6 +137,7 @@ cc_binary(
         ":lcm",
         "@glib",
     ],
+    deprecation = DEPRECATION,
 )
 
 cc_binary(
@@ -143,6 +147,7 @@ cc_binary(
     ],
     copts = LCM_COPTS,
     deps = [":lcm"],
+    deprecation = DEPRECATION,
 )
 
 cc_binary(
@@ -169,6 +174,7 @@ cc_binary(
     deps = [
         "@glib",
     ],
+    deprecation = DEPRECATION,
 )
 
 cc_binary(
@@ -241,6 +247,7 @@ py_library(
     srcs = ["gen/lcm/__init__.py"],  # Shim, from the genrule above.
     imports = ["gen"],
     deps = [":lcm-python-upstream"],
+    deprecation = DEPRECATION,
 )
 
 java_library(
@@ -253,12 +260,14 @@ java_library(
     deps = [
         "@lcm_maven//:net_sf_jchart2d_jchart2d",
     ],
+    deprecation = DEPRECATION,
 )
 
 java_binary(
     name = "lcm-logplayer-gui",
     main_class = "lcm.logging.LogPlayer",
     runtime_deps = [":lcm-java"],
+    deprecation = DEPRECATION,
 )
 
 java_binary(
@@ -272,4 +281,30 @@ java_binary(
     runtime_deps = [
         ":lcm-java",
     ],
+    deprecation = DEPRECATION,
+)
+
+cc_library(
+    name = "lcm_coretypes_non_deprecated",
+    deps = [":lcm_coretypes"],
+    visibility = ["@drake//tools/workspace/lcm:__subpackages__"],
+)
+
+py_library(
+    name = "lcm-python_non_deprecated",
+    deps = [":lcm-python"],
+    visibility = ["@drake//tools/workspace/lcm:__subpackages__"],
+)
+
+java_library(
+    name = "lcm-java_non_deprecated",
+    srcs = glob(["lcm-java/lcm/**/*.java"]),
+    javacopts = ["-XepDisableAllChecks"],
+    deps = ["@lcm_maven//:net_sf_jchart2d_jchart2d"],
+    visibility = ["@drake//tools/workspace/lcm:__subpackages__"],
+)
+
+sh_binary(
+    name = "lcm-gen_non_deprecated",
+    srcs = [":lcm-gen"],
 )

tools/workspace/lcm/repository.bzl

@@ -1,18 +1,16 @@
 load("//tools/workspace:github.bzl", "github_archive")
 
+# Everything here is deprecated for removal on 2026-02-01.
+
 def lcm_repository(
         name,
         mirrors = None):
     github_archive(
         name = name,
         repository = "lcm-proj/lcm",
-        upgrade_advice = """
-        When updating, lcm needs its own pull request separate from the rest of
-        the monthly upgrades.
-        """,
         # TODO(jwnimmer-tri) At the moment we have both @lcm and @lcm_internal
-        # repositories. We are working to deprecate @lcm. In the meantime, be
-        # aware that we have a different pins for each repository.
+        # repositories, with @lcm being deprecated. Be aware that we have
+        # different pins for each repository.
         commit = "v1.5.1",
         sha256 = "40ba0b7fb7c9ad06d05e06b4787d743cf11be30eb4f1a03abf4a92641c5b1203",  # noqa
         build_file = ":package.BUILD.bazel",

tools/workspace/lcm_internal/repository.bzl

@@ -11,8 +11,8 @@ def lcm_internal_repository(
         the monthly upgrades.
         """,
         # TODO(jwnimmer-tri) At the moment we have both @lcm and @lcm_internal
-        # repositories. We are working to deprecate @lcm. In the meantime, be
-        # aware that we have a different pins for each repository.
+        # repositories, with @lcm being deprecated. Be aware that we have
+        # different pins for each repository.
         # TODO(jwnimmer-tri) Once LCM has its next tagged release >v1.5.1, we
         # should switch this back to a release tag instead of this hash.
         commit = "e4bed2c86fbd6dd2280326801acf71cbd05074be",