SERVER-80396 - Establish the logic necessary to invoke clang-tidy via Bazel (#21221)

GitOrigin-RevId: f7cbec42a852f91f299a64ad787cc232cd4dd4bf

.bazelrc

@@ -49,6 +49,14 @@ build --bes_keywords=repo:mongo
 build --jobs=200
 common --remote_upload_local_results=False
 
+# Settings specific for clang-tidy
+--config=clang-tidy
+build:clang-tidy --aspects @bazel_clang_tidy//clang_tidy:clang_tidy.bzl%clang_tidy_aspect
+build:clang-tidy --output_groups=report
+build:clang-tidy --@bazel_clang_tidy//:clang_tidy_config=//:clang_tidy_config
+build:clang-tidy --@bazel_clang_tidy//:clang_tidy_executable=@mongo_toolchain//:clang_tidy
+build:clang-tidy --@bazel_clang_tidy//:clang_tidy_additional_deps=@mongo_toolchain//:all
+
 # if you don't have access to the remote execution cluster above, use the local config
 # described below.
 # pass local config to SCons like:

BUILD.bazel

@@ -18,3 +18,11 @@ alias(
     name = "codeowners",
     actual = "//buildscripts:codeowners",
 )
+
+# This file group makes it possible to set the clang-tidy configuration setting:
+#   --@bazel_clang_tidy//:clang_tidy_config=//:clang_tidy_config
+filegroup(
+    name = "clang_tidy_config",
+    srcs = [".clang-tidy"],
+    visibility = ["//visibility:public"],
+)

WORKSPACE.bazel

@@ -2,6 +2,14 @@ load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
 load("//bazel/platforms:local_config_platform.bzl", "setup_local_config_platform")
 load("//bazel/toolchains:mongo_toolchain.bzl", "toolchain_download")
 
+http_archive(
+    name = "bazel_clang_tidy",
+    # Note: strip_prefix is necessary to refer to the `@bazel_clang_tidy` package
+    strip_prefix = "bazel_clang_tidy-1.1",
+    # TODO(80396): Figure out how to get the sha256 of the release tarball
+    url = "https://github.com/mongodb-forks/bazel_clang_tidy/archive/refs/tags/v1.1.tar.gz",
+)
+
 setup_local_config_platform(name = "local_config_platform")
 
 toolchain_download(name = "mongo_toolchain")

bazel/docs/developer_workflow.md

@@ -99,3 +99,27 @@ This allows SCons build targets to depend on Bazel build targets directly. The B
             'new_library', # depend on the bazel "new_library" target defined above
     	],
     )
+
+## Running clang-tidy via Bazel
+
+Note: This feature is still in development; see https://jira.mongodb.org/browse/SERVER-80396 for details)
+
+To run clang-tidy via Bazel, do the following:
+
+1. (Only necessary once, unless you change the `.clang-tidy.in`) Generate `.clang-tidy` by running `python3 buildscripts/clang_tidy.py`.
+2. To analyze all code, run `bazel build --config=clang-tidy src/...`
+3. To analyze a single target (e.g.: `fsync_locked`), run the following command (note that `_with_debug` suffix on the target): `bazel build --config=clang-tidy src/mongo/db/commands:fsync_locked_with_debug`
+
+Remaining work to do:
+
+- TODO(SERVER-80396): Make it SCons-invokable
+- TODO(SERVER-80396): Link in Mongo's custom clang-tidy rules
+- TODO(SERVER-80396): Make it run in CI
+- TODO(SERVER-80396): Address the concern about [aspect / feature interaction](https://github.com/10gen/mongo/pull/21221#pullrequestreview-2009832686).
+  Testing notes:
+- If you want to test whether clang-tidy is in fact finding bugs, you can inject the following code into a `cpp` file to generate a `bugprone-incorrect-roundings` warning:
+
+```
+const double f = 1.0;
+const int foo = (int)(f + 0.5);
+```

bazel/toolchains/mongo_toolchain.BUILD

@@ -172,3 +172,12 @@ cc_toolchain_suite(
         "{bazel_toolchain_cpu}": ":cc_mongo_toolchain",
     },
 )
+
+# This file group makes it possible to set the clang-tidy configuration setting:
+#   --@bazel_clang_tidy//:clang_tidy_executable=@mongo_toolchain//:clang_tidy
+filegroup(
+    name = "clang_tidy",
+    srcs = [
+        "v4/bin/clang-tidy",
+    ],
+)