Allow bzlmod users to inhibit toolchain registration (#2819)
Partial fix for #2818
diff --git a/rust/extensions.bzl b/rust/extensions.bzl
index 1a8b779..683d11d 100644
--- a/rust/extensions.bzl
+++ b/rust/extensions.bzl
@@ -31,6 +31,17 @@
return root, our_module
+def _empty_repository_impl(repository_ctx):
+ repository_ctx.file("WORKSPACE.bazel", """workspace(name = "{}")""".format(
+ repository_ctx.name,
+ ))
+ repository_ctx.file("BUILD.bazel", "")
+
+_empty_repository = repository_rule(
+ doc = ("Declare an empty repository."),
+ implementation = _empty_repository_impl,
+)
+
def _rust_impl(module_ctx):
# Toolchain configuration is only allowed in the root module, or in
# rules_rust.
@@ -40,18 +51,25 @@
toolchains = root.tags.toolchain or rules_rust.tags.toolchain
for toolchain in toolchains:
- rust_register_toolchains(
- dev_components = toolchain.dev_components,
- edition = toolchain.edition,
- allocator_library = toolchain.allocator_library,
- rustfmt_version = toolchain.rustfmt_version,
- rust_analyzer_version = toolchain.rust_analyzer_version,
- sha256s = toolchain.sha256s,
- extra_target_triples = toolchain.extra_target_triples,
- urls = toolchain.urls,
- versions = toolchain.versions,
- register_toolchains = False,
- )
+ if len(toolchain.versions) == 0:
+ # If the root module has asked for rules_rust to not register default
+ # toolchains, an empty repository named `rust_toolchains` is created
+ # so that the `register_toolchains()` in MODULES.bazel is still
+ # valid.
+ _empty_repository(name = "rust_toolchains")
+ else:
+ rust_register_toolchains(
+ dev_components = toolchain.dev_components,
+ edition = toolchain.edition,
+ allocator_library = toolchain.allocator_library,
+ rustfmt_version = toolchain.rustfmt_version,
+ rust_analyzer_version = toolchain.rust_analyzer_version,
+ sha256s = toolchain.sha256s,
+ extra_target_triples = toolchain.extra_target_triples,
+ urls = toolchain.urls,
+ versions = toolchain.versions,
+ register_toolchains = False,
+ )
_COMMON_TAG_KWARGS = dict(
allocator_library = attr.string(
@@ -92,7 +110,8 @@
versions = attr.string_list(
doc = (
"A list of toolchain versions to download. This paramter only accepts one versions " +
- "per channel. E.g. `[\"1.65.0\", \"nightly/2022-11-02\", \"beta/2020-12-30\"]`."
+ "per channel. E.g. `[\"1.65.0\", \"nightly/2022-11-02\", \"beta/2020-12-30\"]`. " +
+ "May be set to an empty list (`[]`) to inhibit `rules_rust` from registering toolchains."
),
default = _RUST_TOOLCHAIN_VERSIONS,
),
