use protobuf binaries to reduce initial compile times

defs.bzl

@@ -3,10 +3,10 @@ load("@bazel_skylib//lib:versions.bzl", "versions")
 load("@io_bazel_rules_rust//rust:repositories.bzl", "rust_repositories")
 load("@net_ankiweb_anki//cargo:crates.bzl", "raze_fetch_remote_crates")
 load(":python.bzl", "setup_local_python")
+load(":protobuf.bzl", "setup_protobuf_binary")
 load("@build_bazel_rules_nodejs//:index.bzl", "node_repositories", "yarn_install")
 load("@io_bazel_rules_sass//:defs.bzl", "sass_repositories")
 load("@build_bazel_rules_svelte//:defs.bzl", "rules_svelte_dependencies")
-load("@com_google_protobuf//:protobuf_deps.bzl", "protobuf_deps")
 load("@com_github_ali5h_rules_pip//:defs.bzl", "pip_import")
 load("//pip/pyqt5:defs.bzl", "install_pyqt5")
 
@@ -26,6 +26,8 @@ def setup_deps():
 
     setup_local_python(name = "python")
 
+    setup_protobuf_binary(name = "com_google_protobuf")
+
     native.register_toolchains("@python//:python3_toolchain")
 
     pip_import(
@@ -50,5 +52,3 @@ def setup_deps():
     sass_repositories()
 
     rules_svelte_dependencies()
-
-    protobuf_deps()

platforms/README.md

@@ -1,2 +1,2 @@
-Platform constraints. Currently only used to control wheel filenames
-on a per-platform basis.
+Platform constraints, used for things like controlling wheel filenames
+on a per-platform basis, and selecting the correct protobuf binary.

protobuf.bzl

@@ -0,0 +1,63 @@
+"""
+Replace @com_google_protobuf with a platform binary.
+
+Avoids the long initial compile, but will fail if anything depends on the protobuf library.
+"""
+
+load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
+load("@bazel_tools//tools/build_defs/repo:utils.bzl", "maybe")
+
+def _impl(rctx):
+    rctx.file("BUILD.bazel", """
+alias(
+    name = "protoc",
+    actual = select({
+        "@net_ankiweb_anki//platforms:windows_x86_64": "@protoc_bin_windows//:bin/protoc.exe",
+        "@net_ankiweb_anki//platforms:macos_x86_64": "@protoc_bin_macos//:bin/protoc",
+        "@net_ankiweb_anki//platforms:linux_x86_64": "@protoc_bin_linux//:bin/protoc"
+    }),
+    visibility = ["//visibility:public"]
+)
+""")
+
+_setup_protoc = repository_rule(
+    implementation = _impl,
+    local = True,
+    attrs = {},
+)
+
+def setup_protobuf_binary(name):
+    maybe(
+        http_archive,
+        name = "protoc_bin_macos",
+        urls = [
+            "https://github.com/protocolbuffers/protobuf/releases/download/v3.14.0/protoc-3.14.0-osx-x86_64.zip",
+        ],
+        sha256 = "699ceee7ef0988ecf72bf1c146dee5d9d89351a19d4093d30ebea3c04008bb8c",
+        build_file_content = """exports_files(["bin/protoc"])""",
+    )
+
+    maybe(
+        http_archive,
+        name = "protoc_bin_linux",
+        urls = [
+            "https://github.com/protocolbuffers/protobuf/releases/download/v3.14.0/protoc-3.14.0-linux-x86_64.zip",
+        ],
+        sha256 = "a2900100ef9cda17d9c0bbf6a3c3592e809f9842f2d9f0d50e3fba7f3fc864f0",
+        build_file_content = """exports_files(["bin/protoc"])""",
+    )
+
+    maybe(
+        http_archive,
+        name = "protoc_bin_windows",
+        urls = [
+            "https://github.com/protocolbuffers/protobuf/releases/download/v3.14.0/protoc-3.14.0-win64.zip",
+        ],
+        sha256 = "642554ed4dd2dba94e1afddcccdd7d832999cea309299cc5952f13db389894f8",
+        build_file_content = """exports_files(["bin/protoc.exe"])""",
+    )
+
+    if not native.existing_rule(name):
+        _setup_protoc(
+            name = name,
+        )

repos.bzl

@@ -22,19 +22,6 @@ def register_repos():
         ],
     )
 
-    # protobuf
-    ############
-
-    maybe(
-        http_archive,
-        name = "com_google_protobuf",
-        sha256 = "6dd0f6b20094910fbb7f1f7908688df01af2d4f6c5c21331b9f636048674aebf",
-        strip_prefix = "protobuf-3.14.0",
-        urls = [
-            "https://github.com/protocolbuffers/protobuf/releases/download/v3.14.0/protobuf-all-3.14.0.tar.gz",
-        ],
-    )
-
     # rust
     ########