serde/proto: seastar friendly protobuf parser

TODO explain yourself

MODULE.bazel

@@ -71,6 +71,7 @@ use_repo(non_module_dependencies, "hwloc")
 use_repo(non_module_dependencies, "jsoncons")
 use_repo(non_module_dependencies, "krb5")
 use_repo(non_module_dependencies, "libpciaccess")
+use_repo(non_module_dependencies, "libprotobuf_mutator")
 use_repo(non_module_dependencies, "libxml2")
 use_repo(non_module_dependencies, "lksctp")
 use_repo(non_module_dependencies, "numactl")

bazel/repositories.bzl

@@ -80,6 +80,14 @@ def data_dependency():
         url = "https://gitlab.freedesktop.org/xorg/lib/libpciaccess/-/archive/2ec2576cabefef1eaa5dd9307c97de2e887fc347/libpciaccess-2ec2576cabefef1eaa5dd9307c97de2e887fc347.tar.gz",
     )
 
+    http_archive(
+        name = "libprotobuf_mutator",
+        build_file = "//bazel/thirdparty:libprotobuf-mutator.BUILD",
+        integrity = "sha256-KWUbFgNpDJtAO6Kr0eTo1v6iczEOta72jSle9oivFhg=",
+        strip_prefix = "libprotobuf-mutator-b922c8ab9004ef9944982e4f165e2747b13223fa",
+        url = "/~https://github.com/google/libprotobuf-mutator/archive/b922c8ab9004ef9944982e4f165e2747b13223fa.zip",
+    )
+
     http_archive(
         name = "libxml2",
         build_file = "//bazel/thirdparty:libxml2.BUILD",

bazel/thirdparty/libprotobuf-mutator.BUILD

@@ -0,0 +1,24 @@
+# See google/libprotobuf-mutator#91
+
+cc_library(
+    name = "libprotobuf_mutator",
+    srcs = glob(
+        [
+            "src/*.cc",
+            "src/*.h",
+            "port/protobuf.h",
+        ],
+        exclude = [
+          "**/*_test.cc",
+          "src/mutator.h",
+        ],
+    ),
+    hdrs = [
+      "src/mutator.h",
+    ],
+    testonly = 1,
+    include_prefix = "protobuf_mutator",
+    strip_include_prefix = "src",
+    visibility = ["//visibility:public"],
+    deps = ["@protobuf"],
+)

src/v/serde/protobuf/BUILD

@@ -0,0 +1,20 @@
+load("//bazel:build.bzl", "redpanda_cc_library")
+
+redpanda_cc_library(
+    name = "protobuf",
+    srcs = [
+        "parser.cc",
+    ],
+    hdrs = [
+        "parser.h",
+    ],
+    include_prefix = "serde/protobuf",
+    visibility = ["//visibility:public"],
+    deps = [
+        "//src/v/bytes:iobuf",
+        "//src/v/bytes:iobuf_parser",
+        "//src/v/container:chunked_hash_map",
+        "//src/v/container:fragmented_vector",
+        "@protobuf",
+    ],
+)