simplify version handling since we support only one

Author: alexeagle

.github/workflows/release_prep.sh

@@ -37,6 +37,7 @@ mkdir -p ${PREFIX}/bazel/private
 cat >${INTEGRITY_FILE} <<EOF
 "Generated during release by release_prep.sh"
 
+RELEASE_VERSION="${TAG}"
 RELEASED_BINARY_INTEGRITY = $(
 curl -s https://api.github.com/repos/protocolbuffers/protobuf/releases/tags/${TAG} \
   | jq -f <(echo "$filter_releases")

bazel/private/prebuilt_protoc_extension.bzl

@@ -1,18 +1,15 @@
 "Module extensions for use under bzlmod"
 
+load("@bazel_skylib//lib:modules.bzl", "modules")
 load("//toolchain:platforms.bzl", "PROTOBUF_PLATFORMS")
 load("//bazel/private:prebuilt_protoc_toolchain.bzl", "prebuilt_protoc_repo")
 
-def create_all_toolchain_repos(name, version):
+def create_all_toolchain_repos(name = "prebuilt_protoc"):
     for platform in PROTOBUF_PLATFORMS.keys():
         prebuilt_protoc_repo(
             # We must replace hyphen with underscore to workaround rules_python py_proto_library constraint
             name = ".".join([name, platform.replace("-", "_")]),
             platform = platform,
-            version = version,
         )
 
-protoc = module_extension(
-    # TODO: replace version number here during release, maybe with git archive .gitattributes config
-    implementation = lambda module_ctx: create_all_toolchain_repos("prebuilt_protoc", "v33.0")
-)
+protoc = modules.as_extension(create_all_toolchain_repos)

bazel/private/prebuilt_protoc_toolchain.bzl

@@ -1,6 +1,6 @@
 "Repository rule that downloads a pre-compiled protoc from our official release for a single platform."
 
-load(":prebuilt_tool_integrity.bzl", "RELEASED_BINARY_INTEGRITY")
+load(":prebuilt_tool_integrity.bzl", "RELEASED_BINARY_INTEGRITY", "RELEASE_VERSION")
 load("//toolchain:platforms.bzl", "PROTOBUF_PLATFORMS")
 
 def release_version_to_artifact_name(release_version, platform):
@@ -18,14 +18,13 @@ def release_version_to_artifact_name(release_version, platform):
     )
 
 def _prebuilt_protoc_repo_impl(rctx):
-    release_version = rctx.attr.version
     filename = release_version_to_artifact_name(
-        release_version,
+        RELEASE_VERSION,
         rctx.attr.platform,
     )
     rctx.download_and_extract(
         url = "https://github.com/protocolbuffers/protobuf/releases/download/{}/{}".format(
-            release_version,
+            RELEASE_VERSION,
             filename,
         ),
         sha256 = RELEASED_BINARY_INTEGRITY[filename],
@@ -54,9 +53,5 @@ prebuilt_protoc_repo = repository_rule(
             mandatory = True,
             values = PROTOBUF_PLATFORMS.keys(),
         ),
-        "version": attr.string(
-            doc = "Release tag from protocolbuffers/protobuf repo, e.g. 'v25.3'",
-            mandatory = True,
-        ),
     },
 )

bazel/private/prebuilt_tool_integrity.bzl

@@ -6,6 +6,8 @@ so that the integrity of the prebuilt tools is included in the release artifact.
 The checked in content is only here to allow load() statements in the sources to resolve.
 """
 
+RELEASE_VERSION = "v33.0"
+
 # Fetched from the last release of protobuf, so the example can work
 RELEASED_BINARY_INTEGRITY = {
   "MODULE.bazel.intoto.jsonl": "32ee438bf7e3a210a6b7d5e2d272900a2e7f4a1b4f0992fdf0490281771cac3e",

bazel/private/toolchains/prebuilt/BUILD.bazel

@@ -1,27 +1,7 @@
 """Create lazy definitions to reference the pre-built protoc toolchains.
 
 Ensures that Bazel only downloads required binaries for selected toolchains.
-
-This follows guidance here:
-https://docs.bazel.build/versions/main/skylark/deploying.html#registering-toolchains
-"
-Note that in order to resolve toolchains in the analysis phase
-Bazel needs to analyze all toolchain targets that are registered.
-Bazel will not need to analyze all targets referenced by toolchain.toolchain attribute.
-If in order to register toolchains you need to perform complex computation in the repository,
-consider splitting the repository with toolchain targets
-from the repository with <LANG>_toolchain targets.
-Former will be always fetched,
-and the latter will only be fetched when user actually needs to build <LANG> code.
-"
-
-The "complex computation" in our case is simply downloading our pre-built protoc binaries.
-This guidance tells us how to avoid that: we put the toolchain targets in the alias repository
-with only the toolchain attribute pointing into the platform-specific repositories.
-
-These can be registered in the workspace file or passed to --extra_toolchains flag.
-By default all these toolchains are registered by the protoc module extension
-so users don't normally need to interact with these targets.
+In particular, see comment below on the toolchain#toolchain attribute.
 """
 
 load("//toolchain:platforms.bzl", "PROTOBUF_PLATFORMS")