0002-Switch-to-toolchains.patch

From d2e4671e04bd72211d15183f891707c4ff2f11cd Mon Sep 17 00:00:00 2001
From: Fabian Meumertzheim <fabian@meumertzhe.im>
Date: Mon, 16 Dec 2024 22:20:13 +0100
Subject: [PATCH 2/2] Switch to toolchains

---
 bazel/private/BUILD |  6 ------
 protobuf.bzl        | 41 ++++++++++++++++++++++++++++++-----------
 2 files changed, 30 insertions(+), 17 deletions(-)

diff --git a/bazel/private/BUILD b/bazel/private/BUILD
index a5b3abeda..8c1c94ac8 100644
--- a/bazel/private/BUILD
+++ b/bazel/private/BUILD
@@ -1,5 +1,4 @@
 load("@bazel_skylib//:bzl_library.bzl", "bzl_library")
-load(":current_protoc.bzl", "current_protoc")
 load(":native_bool_flag.bzl", "native_bool_flag")
 
 package(default_applicable_licenses = ["//:license"])
@@ -29,11 +28,6 @@ toolchain_type(
     visibility = ["//visibility:public"],
 )
 
-current_protoc(
-    name = "current_protoc",
-    visibility = ["//:__subpackages__"],
-)
-
 bzl_library(
     name = "upb_proto_library_internal_bzl",
     srcs = [
diff --git a/protobuf.bzl b/protobuf.bzl
index 736cc19cf..acb190942 100644
--- a/protobuf.bzl
+++ b/protobuf.bzl
@@ -1,8 +1,9 @@
 load("@bazel_skylib//lib:versions.bzl", "versions")
 load("@rules_cc//cc:defs.bzl", "objc_library")
 load("@rules_python//python:defs.bzl", "py_library")
+load("//bazel/common:proto_common.bzl", "proto_common")
 load("//bazel/common:proto_info.bzl", "ProtoInfo")
-load("//bazel/private:current_protoc.bzl", "ProtocFilesToRun")
+load("//bazel/private:toolchain_helpers.bzl", "toolchains")
 
 def _GetPath(ctx, path):
     if ctx.label.workspace_root:
@@ -72,6 +73,26 @@ def _CsharpOuts(srcs):
         for src in srcs
     ]
 
+_PROTOC_ATTRS = toolchains.if_legacy_toolchain({
+    "_proto_compiler": attr.label(
+        cfg = "exec",
+        executable = True,
+        allow_files = True,
+        default = configuration_field("proto", "proto_compiler"),
+    ),
+})
+_PROTOC_FRAGMENTS = ["proto"]
+_PROTOC_TOOLCHAINS = toolchains.use_toolchain(toolchains.PROTO_TOOLCHAIN)
+
+def _protoc_files_to_run(ctx):
+    if proto_common.INCOMPATIBLE_ENABLE_PROTO_TOOLCHAIN_RESOLUTION:
+        toolchain = ctx.toolchains[toolchains.PROTO_TOOLCHAIN]
+        if not toolchain:
+            fail("Protocol compiler toolchain could not be resolved.")
+        return toolchain.proto.proto_compiler
+    else:
+        return ctx.attr._proto_compiler[DefaultInfo].files_to_run
+
 ProtoGenInfo = provider(
     fields = ["srcs", "import_flags", "deps"],
 )
@@ -311,7 +332,7 @@ def _internal_gen_well_known_protos_java_impl(ctx):
             args.add_all([src.path[offset:] for src in dep.direct_sources])
 
     ctx.actions.run(
-        executable = ctx.attr._protoc[ProtocFilesToRun].files_to_run,
+        executable = _protoc_files_to_run(ctx),
         inputs = descriptors,
         outputs = [srcjar],
         arguments = [args],
@@ -335,10 +356,9 @@ internal_gen_well_known_protos_java = rule(
         "javalite": attr.bool(
             default = False,
         ),
-        "_protoc": attr.label(
-            default = "//bazel/private:current_protoc",
-        ),
-    },
+    } | _PROTOC_ATTRS,
+    fragments = _PROTOC_FRAGMENTS,
+    toolchains = _PROTOC_TOOLCHAINS,
 )
 
 def _internal_gen_kt_protos(ctx):
@@ -372,7 +392,7 @@ def _internal_gen_kt_protos(ctx):
             args.add_all([src.path[offset:] for src in dep.direct_sources])
 
     ctx.actions.run(
-        executable = ctx.attr._protoc[ProtocFilesToRun].files_to_run,
+        executable = _protoc_files_to_run(ctx),
         inputs = descriptors,
         outputs = [srcjar],
         arguments = [args],
@@ -396,10 +416,9 @@ internal_gen_kt_protos = rule(
         "lite": attr.bool(
             default = False,
         ),
-        "_protoc": attr.label(
-            default = "//bazel/private:current_protoc",
-        ),
-    },
+    } | _PROTOC_ATTRS,
+    fragments = _PROTOC_FRAGMENTS,
+    toolchains = _PROTOC_TOOLCHAINS,
 )
 
 def internal_objc_proto_library(
-- 
2.49.0