bazel: add explicit rust test shard labels

BUILD.bazel

@@ -37,6 +37,8 @@ alias(
 
 exports_files([
     "AGENTS.md",
+    "test_binary_test_launcher.bat.tpl",
+    "test_binary_test_launcher.sh.tpl",
     "workspace_root_test_launcher.bat.tpl",
     "workspace_root_test_launcher.sh.tpl",
 ])

MODULE.bazel

@@ -94,25 +94,40 @@ single_version_override(
 )
 
 rules_rust = use_extension("@rules_rs//rs/experimental:rules_rust.bzl", "rules_rust")
-# Build-script probe binaries inherit CFLAGS/CXXFLAGS from Bazel's C++
-# toolchain. On `windows-gnullvm`, llvm-mingw does not ship
-# `libssp_nonshared`, so strip the forwarded stack-protector flags there.
-rules_rust.patch(
+
+bazel_dep(name = "rules_rust", version = "0.69.0")
+
+# `rules_rs` 0.0.43 pins an older hermeticbuild/rules_rust commit. Override the
+# extension-created repo so Codex can use rust_test sharding from #14 without
+# updating the entire rules_rs module.
+#
+# Build-script probe binaries inherit CFLAGS/CXXFLAGS from Bazel's C++ toolchain.
+# On `windows-gnullvm`, llvm-mingw does not ship `libssp_nonshared`, so strip the
+# forwarded stack-protector flags there.
+archive_override(
+    module_name = "rules_rust",
+    integrity = "sha256-q37yA5WS3++LIgdkThIhxsQkoZ5F/+DD4GhTWkY1rkE=",
+    patch_strip = 1,
     patches = [
         "//patches:rules_rust_windows_gnullvm_build_script.patch",
         "//patches:rules_rust_windows_exec_msvc_build_script_env.patch",
         "//patches:rules_rust_windows_bootstrap_process_wrapper_linker.patch",
         "//patches:rules_rust_windows_build_script_runner_paths.patch",
         "//patches:rules_rust_windows_msvc_direct_link_args.patch",
         "//patches:rules_rust_windows_process_wrapper_skip_temp_outputs.patch",
+        "//patches:rules_rust_stable_explicit_test_shards.patch",
         "//patches:rules_rust_windows_exec_bin_target.patch",
         "//patches:rules_rust_windows_exec_std.patch",
         "//patches:rules_rust_windows_exec_rustc_dev_rlib.patch",
-        "//patches:rules_rust_repository_set_exec_constraints.patch",
     ],
-    strip = 1,
+    strip_prefix = "rules_rust-10825e1a40b8f6d979c51bc795c9d3fa7f78cc6f",
+    urls = ["https://github.com/hermeticbuild/rules_rust/archive/10825e1a40b8f6d979c51bc795c9d3fa7f78cc6f.tar.gz"],
+)
+
+override_repo(
+    rules_rust,
+    rules_rust = "rules_rust",
 )
-use_repo(rules_rust, "rules_rust")
 
 nightly_rust = use_extension(
     "@rules_rs//rs/experimental:rules_rust_reexported_extensions.bzl",

codex-rs/app-server/BUILD.bazel

@@ -4,5 +4,9 @@ codex_rust_crate(
     name = "app-server",
     crate_name = "codex_app_server",
     integration_test_timeout = "long",
+    test_shard_counts = {
+        "app-server-all-test": 8,
+        "app-server-unit-tests": 8,
+    },
     test_tags = ["no-sandbox"],
 )

codex-rs/core/BUILD.bazel

@@ -47,6 +47,10 @@ codex_rust_crate(
         # succeeds without this workaround.
         "//:AGENTS.md",
     ],
+    test_shard_counts = {
+        "core-all-test": 8,
+        "core-unit-tests": 8,
+    },
     test_tags = ["no-sandbox"],
     unit_test_timeout = "long",
     extra_binaries = [

codex-rs/tui/BUILD.bazel

@@ -19,6 +19,9 @@ codex_rust_crate(
         "src/**/*.rs",
         "src/**/snapshots/**",
     ]) + ["//codex-rs/core:model_availability_nux_fixtures"],
+    test_shard_counts = {
+        "tui-unit-tests": 8,
+    },
     integration_compile_data_extra = ["src/test_backend.rs"],
     extra_binaries = [
         "//codex-rs/cli:codex",