Add option_deps to proto_library for import option.

`option_deps` are passed to protoc as `--option_dependencies` for resolution of option imports, but should not be included in the outputted descriptor set or considered by <lang>_proto_library aspects (i.e. `attr_aspects`) for gencode output.

PiperOrigin-RevId: 743679882

Author: zhangskz

.github/workflows/test_bazel.yml

@@ -27,6 +27,8 @@ jobs:
       fail-fast: false
       matrix:
         runner: [ ubuntu, windows, macos ]
+        # Bazel < 7.3.0 depends on rules_proto version that doesn't have @rules_proto//proto:toolchain_type target used by Bazel
+        # https://github.com/bazelbuild/bazel/blob/a82541b93897216ec9c0ab48eaa8fd95c2995864/src/main/starlark/builtins_bzl/common/proto/proto_semantics.bzl#L20
         bazelversion: [ '7.1.2', '8.0.0' ]
         bzlmod: [ true, false ]
         toolchain_resolution: [ "", "--incompatible_enable_proto_toolchain_resolution=true" ]
@@ -67,7 +69,7 @@ jobs:
         uses: protocolbuffers/protobuf-ci/bazel@v4
         with:
           credentials: ${{ secrets.GAR_SERVICE_ACCOUNT }}
-          bazel-cache: examples
+          bazel-cache: examples-${{ matrix.bazelversion }}-${{ matrix.bzlmod }}-${{ matrix.toolchain_resolution }}
           version: ${{ matrix.bazelversion }}
           bash: >
             cd examples;

MODULE.bazel

@@ -46,6 +46,14 @@ bazel_dep(name = "rules_license", version = "1.0.0")
 bazel_dep(name = "rules_pkg", version = "1.0.1")
 bazel_dep(name = "rules_python", version = "1.0.0")
 
+# Pin to rules_proto to 7.1.0 to avoid toolchain incompatibilities when
+# --incompatible_enable_proto_toolchain_resolution=true in Bazel 7.
+# rules_proto 7.0.2 from deps incorrectly rules_proto's toolchain_type but protobuf's toolchain, but
+# 7.0.3+ uses protobuf's toolchain and toolchain_type but 7.0.3 isn't on BCR.
+# TODO: Restore as dev_dependency once Bazel 7 is dropped or pin is no longer needed.
+# rules_proto is needed for @com_google_protobuf_v25 used in //compatibility/... tests
+bazel_dep(name = "rules_proto", version = "7.1.0")
+
 bazel_dep(name = "rules_rust", version = "0.56.0", dev_dependency = True)
 bazel_dep(name = "rules_ruby", version = "0.17.3", dev_dependency = True)
 
@@ -82,6 +90,7 @@ ruby.toolchain(
     version = "system",
 )
 use_repo(ruby, "ruby")
+
 ruby.bundle_fetch(
     name = "protobuf_bundle",
     gem_checksums = {
@@ -227,9 +236,6 @@ bazel_dep(
 cc_configure = use_extension("@rules_cc//cc:extensions.bzl", "cc_configure_extension")
 use_repo(cc_configure, "local_config_cc")
 
-# rules_proto are needed for @com_google_protobuf_v25 used in //compatibility/... tests
-bazel_dep(name = "rules_proto", version = "7.0.2", dev_dependency = True)
-
 # For the Lua upb implementation
 bazel_dep(name = "lua", version = "5.4.6", dev_dependency = True)
 

bazel/private/proto_info.bzl

@@ -34,12 +34,13 @@ def _from_root(root, repo, relpath):
         #   - with sibling layout: `{root}/package/path`
         return _join(root, "" if repo.startswith("../") else repo, relpath)
 
-def _create_proto_info(*, srcs, deps, descriptor_set, proto_path = "", workspace_root = "", bin_dir = None, allow_exports = None):
+def _create_proto_info(*, srcs, deps, descriptor_set, option_deps = [], proto_path = "", workspace_root = "", bin_dir = None, allow_exports = None):
     """Constructs ProtoInfo.
 
     Args:
       srcs: ([File]) List of .proto files (possibly under _virtual path)
       deps: ([ProtoInfo]) List of dependencies
+      option_deps: ([ProtoInfo]) List of option dependencies
       descriptor_set: (File) Descriptor set for this Proto
       proto_path: (str) Path that should be stripped from files in srcs. When
         stripping is needed, the files should be symlinked into `_virtual_imports/target_name`
@@ -61,6 +62,8 @@ def _create_proto_info(*, srcs, deps, descriptor_set, proto_path = "", workspace
             fail("srcs parameter expects all files to have the same workspace_root: ", workspace_root)
         if not src.short_path.startswith(src_prefix):
             fail("srcs parameter expects all files start with %s" % src_prefix)
+    if not srcs and option_deps:
+        fail("option_deps parameter should not be set when srcs is empty")
     if type(descriptor_set) != "File":
         fail("descriptor_set parameter expected to be a File")
     if proto_path:
@@ -71,9 +74,10 @@ def _create_proto_info(*, srcs, deps, descriptor_set, proto_path = "", workspace
         if not bin_dir:
             fail("bin_dir parameter should be set when _virtual_imports are used")
 
+    protoc_deps = deps + option_deps
     transitive_sources = depset(
         direct = srcs,
-        transitive = [dep.transitive_sources for dep in deps],
+        transitive = [dep.transitive_sources for dep in protoc_deps],
         order = "preorder",
     )
 
@@ -82,14 +86,15 @@ def _create_proto_info(*, srcs, deps, descriptor_set, proto_path = "", workspace
     root_paths = _uniq([src.root.path for src in srcs])
     transitive_proto_path = depset(
         direct = [_empty_to_dot(_from_root(root, workspace_root, proto_path)) for root in root_paths],
-        transitive = [dep.transitive_proto_path for dep in deps],
+        transitive = [dep.transitive_proto_path for dep in protoc_deps],
     )
 
     if srcs:
         check_deps_sources = depset(direct = srcs)
     else:
         check_deps_sources = depset(transitive = [dep.check_deps_sources for dep in deps])
 
+    # Exclude option_deps from transitive descriptor sets.
     transitive_descriptor_sets = depset(
         direct = [descriptor_set],
         transitive = [dep.transitive_descriptor_sets for dep in deps],
@@ -122,11 +127,11 @@ ProtoInfo, _ = provider(
     fields = {
         "direct_sources": "(list[File]) The `.proto` source files from the `srcs` attribute.",
         "transitive_sources": """(depset[File]) The `.proto` source files from this rule and all
-                    its dependent protocol buffer rules.""",
+                    its `deps` and `option_deps` protocol buffer rules.""",
         "direct_descriptor_set": """(File) The descriptor set of the direct sources. If no srcs,
             contains an empty file.""",
         "transitive_descriptor_sets": """(depset[File]) A set of descriptor set files of all
-            dependent `proto_library` rules, and this one's. This is not the same as passing
+            its `deps` `proto_library` rules, and this one's. Excludes `option_deps`. This is not the same as passing
             --include_imports to proto-compiler. Will be empty if no dependencies.""",
         "proto_source_root": """(str) The directory relative to which the `.proto` files defined in
             the `proto_library` are defined. For example, if this is `a/b` and the rule has the
@@ -147,10 +152,10 @@ ProtoInfo, _ = provider(
             This will make it possible to fix `proto_library` in the future.
             """,
         "transitive_proto_path": """(depset(str) A set of `proto_source_root`s collected from the
-            transitive closure of this rule.""",
+            transitive closure of this rule's `deps` and `option_deps`.""",
         "check_deps_sources": """(depset[File]) The `.proto` sources from the 'srcs' attribute.
             If the library is a proxy library that has no sources, it contains the
-            `check_deps_sources` from this library's direct deps.""",
+            `check_deps_sources` from this library's direct `deps`.""",
         "allow_exports": """(Target) The packages where this proto_library can be exported.""",
 
         # Deprecated fields:

bazel/private/proto_library_rule.bzl

@@ -15,10 +15,14 @@ load("//bazel/common:proto_common.bzl", "proto_common")
 load("//bazel/common:proto_info.bzl", "ProtoInfo")
 load("//bazel/private:toolchain_helpers.bzl", "toolchains")
 
-STRICT_DEPS_FLAG_TEMPLATE = (
-    #
+DIRECT_DEPS_FLAG_TEMPLATE = (
     "--direct_dependencies_violation_msg=" +
-    "%%s is imported, but %s doesn't directly depend on a proto_library that 'srcs' it."
+    "%%s is imported, but %s doesn't have direct `deps` on a proto_library that 'srcs' it."
+)
+
+OPTION_DEPS_FLAG_TEMPLATE = (
+    "--option_dependencies_violation_msg=" +
+    "%%s is option imported, but %s doesn't have direct `option_deps` on a proto_library that 'srcs' it."
 )
 
 def _check_srcs_package(target_package, srcs):
@@ -63,6 +67,7 @@ def _proto_library_impl(ctx):
     _check_srcs_package(ctx.label.package, ctx.attr.srcs)
     srcs = ctx.files.srcs
     deps = [dep[ProtoInfo] for dep in ctx.attr.deps]
+    option_deps = [dep[ProtoInfo] for dep in ctx.attr.option_deps]
     exports = [dep[ProtoInfo] for dep in ctx.attr.exports]
     import_prefix = _get_import_prefix(ctx)
     strip_import_prefix = _get_strip_import_prefix(ctx)
@@ -77,17 +82,19 @@ def _proto_library_impl(ctx):
 
     proto_path, virtual_srcs = _process_srcs(ctx, srcs, import_prefix, strip_import_prefix)
     descriptor_set = ctx.actions.declare_file(ctx.label.name + "-descriptor-set.proto.bin")
+
     proto_info = ProtoInfo(
         srcs = virtual_srcs,
         deps = deps,
         descriptor_set = descriptor_set,
+        option_deps = option_deps,
         proto_path = proto_path,
         workspace_root = ctx.label.workspace_root,
         bin_dir = ctx.bin_dir.path,
         allow_exports = ctx.attr.allow_exports,
     )
 
-    _write_descriptor_set(ctx, proto_info, deps, exports, descriptor_set)
+    _write_descriptor_set(ctx, proto_info, deps, option_deps, exports, descriptor_set)
 
     # We assume that the proto sources will not have conflicting artifacts
     # with the same root relative path
@@ -154,13 +161,13 @@ def _symlink_to_virtual_imports(ctx, srcs, import_prefix, strip_import_prefix):
         virtual_srcs.append(virtual_src)
     return proto_path, virtual_srcs
 
-def _write_descriptor_set(ctx, proto_info, deps, exports, descriptor_set):
+def _write_descriptor_set(ctx, proto_info, deps, option_deps, exports, descriptor_set):
     """Writes descriptor set."""
     if proto_info.direct_sources == []:
         ctx.actions.write(descriptor_set, "")
         return
 
-    dependencies_descriptor_sets = depset(transitive = [dep.transitive_descriptor_sets for dep in deps])
+    dependencies_descriptor_sets = depset(transitive = [dep.transitive_descriptor_sets for dep in deps + option_deps])
 
     args = ctx.actions.args()
 
@@ -191,7 +198,22 @@ def _write_descriptor_set(ctx, proto_info, deps, exports, descriptor_set):
             args.add("--direct_dependencies=")
 
         # Set `-direct_dependencies_violation_msg=`
-        args.add(ctx.label, format = STRICT_DEPS_FLAG_TEMPLATE)
+        args.add(ctx.label, format = DIRECT_DEPS_FLAG_TEMPLATE)
+
+        # option_deps can't be set unless sources is non-empty.
+        option_importable_sources = depset(
+            direct = proto_info.direct_sources,
+            transitive = [dep.check_deps_sources for dep in option_deps],
+        )
+        args.add_joined(
+            "--option_dependencies",
+            option_importable_sources,
+            map_each = proto_common.get_import_path,
+            join_with = ":",
+        )
+
+        # Set `-option_dependencies_violation_msg=`
+        args.add(ctx.label, format = OPTION_DEPS_FLAG_TEMPLATE)
 
     strict_imports = ctx.attr._strict_public_imports[BuildSettingInfo].value
     if strict_imports:
@@ -206,6 +228,7 @@ def _write_descriptor_set(ctx, proto_info, deps, exports, descriptor_set):
                 map_each = proto_common.get_import_path,
                 join_with = ":",
             )
+
     if proto_common.INCOMPATIBLE_ENABLE_PROTO_TOOLCHAIN_RESOLUTION:
         toolchain = ctx.toolchains[toolchains.PROTO_TOOLCHAIN]
         if not toolchain:
@@ -283,6 +306,13 @@ This pattern can be used to e.g. export a public api under a persistent name."""
             doc = """
 The list of other <code>proto_library</code> rules that the target depends upon.
 A <code>proto_library</code> may only depend on other <code>proto_library</code>
+targets. It may not depend on language-specific libraries.""",
+        ),
+        "option_deps": attr.label_list(
+            providers = [ProtoInfo],
+            doc = """
+The list of other <code>proto_library</code> rules that the target depends upon for options only.
+A <code>proto_library</code> may only depend on other <code>proto_library</code>
 targets. It may not depend on language-specific libraries.""",
         ),
         "exports": attr.label_list(

bazel/proto_library.bzl

@@ -11,8 +11,8 @@ load("@proto_bazel_features//:features.bzl", "bazel_features")
 load("//bazel/private:proto_library_rule.bzl", _proto_library = "proto_library")
 
 def proto_library(**kwattrs):
-    # This condition causes Starlark rules to be used only on Bazel >=7.0.0
-    if bazel_features.proto.starlark_proto_info:
+    # Only use Starlark rules when they are removed from Bazel.
+    if not hasattr(native, "proto_library"):
         _proto_library(**kwattrs)
     else:
         # On older Bazel versions keep using native rules, so that mismatch in ProtoInfo doesn't happen

protobuf_deps.bzl

@@ -53,6 +53,16 @@ def _github_archive(repo, commit, **kwargs):
 def protobuf_deps():
     """Loads common dependencies needed to compile the protobuf library."""
 
+    # Pin rules_proto since Bazel 7 otherwise depends on rules_proto 5.3.0-21.7 which is missing
+    # @rules_proto//proto:toolchain_type used by Bazel.
+    # 6.0.0 should work too but would require users to add `register_toolchains` for rules_proto
+    # to their WORKSPACE files.
+    if not native.existing_rule("rules_proto"):
+        http_archive(
+            name = "rules_proto",
+            strip_prefix = "rules_proto-7.1.0",
+            url = "https://github.com/bazelbuild/rules_proto/releases/download/7.1.0/rules_proto-7.1.0.tar.gz",
+        )
     if not native.existing_rule("bazel_features"):
         http_archive(
             name = "bazel_features",