flatbuffers: Add opt-in buffer identification mechanism

score/flatbuffers/bazel/BUILD

@@ -0,0 +1,24 @@
+# *******************************************************************************
+# Copyright (c) 2026 Contributors to the Eclipse Foundation
+#
+# See the NOTICE file(s) distributed with this work for additional
+# information regarding copyright ownership.
+#
+# This program and the accompanying materials are made available under the
+# terms of the Apache License Version 2.0 which is available at
+# https://www.apache.org/licenses/LICENSE-2.0
+#
+# SPDX-License-Identifier: Apache-2.0
+# *******************************************************************************
+
+load("@rules_python//python:defs.bzl", "py_binary")
+
+py_binary(
+    name = "inject_buffer_version",
+    srcs = ["inject_buffer_version.py"],
+    # "manual" excludes this target from wildcard builds (e.g. //score/...) so it is not
+    # built directly for a cross-compilation target platform. It is only ever built for the
+    # exec (host) platform when referenced as a tool via cfg = "exec" in the starlark rules.
+    tags = ["manual"],
+    visibility = ["//visibility:public"],
+)

score/flatbuffers/bazel/codegen.bzl

@@ -22,6 +22,10 @@ def _generate_cpp_impl(ctx):
     # Get the flatc compiler using absolute path from flatbuffers repository
     flatc = ctx.executable._flatc
 
+    # Collect include directories from included .fbs files
+    include_files = ctx.files.includes + [ctx.file._buffer_version_fbs]
+    include_dirs = {files.dirname: True for files in include_files}
+
     # flatc generates <basename>_generated.h by default
     # Use temporary subdirectory based on target to avoid conflicts
     default_name = fbs_file.basename.replace(".fbs", "_generated.h")
@@ -81,11 +85,13 @@ def _generate_cpp_impl(ctx):
     args.add("--cpp")
     args.add("--cpp-std", "c++11")
     args.add("--scoped-enums")
+    for inc_dir in include_dirs:
+        args.add("-I", inc_dir)
     args.add("-o", generated_file.dirname)
     args.add(fbs_file.path)
 
     ctx.actions.run(
-        inputs = [fbs_file],
+        inputs = [fbs_file] + include_files,
         outputs = [generated_file],
         executable = flatc,
         arguments = [args],
@@ -110,23 +116,38 @@ generate_cpp = rule(
             mandatory = True,
             doc = "The name of the generated C++ header file",
         ),
+        "includes": attr.label_list(
+            allow_files = [".fbs"],
+            default = [],
+            doc = "Additional .fbs files required to resolve include directives in the schema.",
+        ),
         "_flatc": attr.label(
             default = "@flatbuffers//:flatc",
             executable = True,
             cfg = "exec",
             doc = "The flatc compiler (absolute path from flatbuffers repository)",
         ),
+        "_buffer_version_fbs": attr.label(
+            default = "@score_baselibs//score/flatbuffers/common:buffer_version.fbs",
+            allow_single_file = [".fbs"],
+            doc = "Automatically included buffer_version.fbs for common buffer version support.",
+        ),
     },
     doc = """Generates a C++ header file from a FlatBuffer schema (.fbs) file.
-    
+
     This rule uses the flatc compiler from the @flatbuffers repository with
     absolute paths, making it usable outside of this repository.
-
+
+    @score_baselibs//score/flatbuffers/common:buffer_version.fbs is always included
+    automatically. The schema must include buffer_version.fbs manually if it uses
+    the common buffer version (e.g. `include "buffer_version.fbs";`).
+
     Example:
         generate_cpp(
             name = "demo_flatbuffer",
             schema = "demo.fbs",
             output = "demo_config.h",
+            includes = ["some_other.fbs"],
         )
     """,
 )

score/flatbuffers/bazel/inject_buffer_version.py

@@ -0,0 +1,70 @@
+#!/usr/bin/env python3
+# *******************************************************************************
+# Copyright (c) 2026 Contributors to the Eclipse Foundation
+#
+# See the NOTICE file(s) distributed with this work for additional
+# information regarding copyright ownership.
+#
+# This program and the accompanying materials are made available under the
+# terms of the Apache License Version 2.0 which is available at
+# https://www.apache.org/licenses/LICENSE-2.0
+#
+# SPDX-License-Identifier: Apache-2.0
+# *******************************************************************************
+
+"""Patches a JSON data file with buffer version information.
+
+This script is invoked by the serialize_buffer Bazel rule to inject
+major_version and minor_version into the user's JSON data file before
+flatc serialization. The version is stored as a 'version' object at
+the top level of the JSON.
+
+Usage:
+    inject_buffer_version.py --input <input.json> --output <output.json> \
+                     --major <major_version> --minor <minor_version>
+"""
+
+import argparse
+import json
+
+
+def main():
+    parser = argparse.ArgumentParser(
+        description="Patch a JSON data file with buffer version information."
+    )
+    parser.add_argument("--input", required=True, help="Input JSON file path")
+    parser.add_argument("--output", required=True, help="Output patched JSON file path")
+    parser.add_argument(
+        "--major", type=int, required=True, help="Major version number (0-65535)"
+    )
+    parser.add_argument(
+        "--minor", type=int, required=True, help="Minor version number (0-65535)"
+    )
+
+    args = parser.parse_args()
+
+    _UINT16_MAX = 65535
+    if not (0 <= args.major <= _UINT16_MAX):
+        parser.error(
+            f"--major {args.major} is out of uint16_t range [0, {_UINT16_MAX}]"
+        )
+    if not (0 <= args.minor <= _UINT16_MAX):
+        parser.error(
+            f"--minor {args.minor} is out of uint16_t range [0, {_UINT16_MAX}]"
+        )
+
+    with open(args.input, "r") as f:
+        data = json.load(f)
+
+    data["version_info"] = {
+        "major_version": args.major,
+        "minor_version": args.minor,
+    }
+
+    with open(args.output, "w") as f:
+        json.dump(data, f, indent=2)
+        f.write("\n")
+
+
+if __name__ == "__main__":
+    main()