Licensing Issue: StackOverflow Attribution in Multiple Files

[vko-insiders]

Multiple files in the codebase contain code with StackOverflow attribution, which may create unintended licensing conflicts with the project's Apache-2.0 license.

Affected Files
File 1: src/aws-cpp-sdk-core/include/aws/core/utils/UnreferencedParam.h
Current content:

/**
 * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
 * SPDX-License-Identifier: Apache-2.0.
 */
#pragma once
// taken from http://stackoverflow.com/questions/3020584/avoid-warning-unreferenced-formal-parameter, ugly but avoids having to #include the definition of an unreferenced struct/class
#if defined (_MSC_VER)
    #define AWS_UNREFERENCED_PARAM(x) (&reinterpret_cast<const int &>(x))
#else
    #define AWS_UNREFERENCED_PARAM(x) ((void)(x))
#endif // _MSC_VER

File 2: crt/aws-crt-cpp/crt/aws-c-common/include/aws/common/macros.h
Problematic section:

/* https://stackoverflow.com/questions/9183993/msvc-variadic-macro-expansion */
#define GLUE(x, y) x y
#define RETURN_ARG_COUNT(_1_, _2_, _3_, _4_, _5_, count, ...) count
#define EXPAND_ARGS(args) RETURN_ARG_COUNT args
#define COUNT_ARGS_MAX5(...) EXPAND_ARGS((__VA_ARGS__, 5, 4, 3, 2, 1, 0))
#define OVERLOAD_MACRO2(name, count) name##count
#define OVERLOAD_MACRO1(name, count) OVERLOAD_MACRO2(name, count)
#define OVERLOAD_MACRO(name, count) OVERLOAD_MACRO1(name, count)
#define CALL_OVERLOAD(name, ...) GLUE(OVERLOAD_MACRO(name, COUNT_ARGS_MAX5(__VA_ARGS__)), (__VA_ARGS__))

Problem
Both files explicitly reference StackOverflow posts as the source of the code. According to StackOverflow's terms of service, user contributions are licensed under CC BY-SA 3.0 (or later versions). This creates a potential licensing conflict:

• License Incompatibility: CC BY-SA 3.0 is a copyleft license that requires derivative works to be licensed under the same terms, which conflicts with the Apache-2.0 license declared in this file and used throughout the AWS SDK.
• Attribution Requirement: CC BY-SA 3.0 requires proper attribution to the original author(s) from StackOverflow, which is not currently provided.
• Downstream Impact: This licensing ambiguity could affect users of the AWS SDK who need clear license compliance.

Analysis
While the code in both cases is relatively simple and likely does not meet the threshold of originality required for copyright protection, the explicit references to StackOverflow as the source create legal uncertainty and could be interpreted as acknowledgment that the code is derived from CC BY-SA licensed material.

This is particularly concerning because:

• The code appears to be copied verbatim from the StackOverflow posts
• The comments explicitly attribute the source
• No CC BY-SA attribution is provided (author names, links to specific answers, etc.)

Suggested Solutions

1. Remove the StackOverflow reference and keep the implementation, since such simple macro definitions are likely not copyrightable
2. Provide proper CC BY-SA attribution if the code is considered derived from StackOverflow (though this may complicate the license)
3. Rewrite the macros independently with a clean-room implementation to avoid any licensing concerns
4. Add clarification that the StackOverflow post inspired the solution but the implementation is original

Recommendation
I recommend option 1 or 3: either remove the attribution (if the code is considered too simple to be copyrightable) or implement a clean version without reference to external sources. This would eliminate any licensing ambiguity and ensure the file is unambiguously Apache-2.0 licensed as intended.
Thank you for maintaining this excellent SDK. Please let me know if you need any additional information or clarification on this issue.