OTIO Submodule Update Stuck On Std::any C++ Version Issue

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Introduction

The OpenTimelineIO (OTIO) submodule update has been experiencing issues with the C++ version, specifically with the std::any type. This problem has been observed in the Swift bindings, where Dependabot updates to the OTIO version are stuck due to a C++ version issue. In this article, we will delve into the problem, explore the example build errors, and discuss the potential solution to resolve this issue.

Understanding the Problem

The issue arises from the use of the std::any type in the OTIO C++ code. The std::any type is a new addition to the C++ standard library, introduced in C++17. However, the OTIO code is not explicitly specifying the C++ version, which is causing the build errors. The errors indicate that the compiler is unable to find the std::any type in the std:: namespace.

Example Build Errors

The following build errors are a result of the C++ version issue:

In file included from /Users/runner/work/OpenTimelineIO-Swift-Bindings/OpenTimelineIO-Swift-Bindings/OpenTimelineIO/src/opentimelineio/serializableObject.h:9:
/Users/runner/work/OpenTimelineIO-Swift-Bindings/OpenTimelineIO-Swift-Bindings/OpenTimelineIO/src/opentimelineio/anyDictionary.h:29:58: error: no member named 'any' in namespace 'std'
class AnyDictionary : private std::map<std::string, std::any>
                                                    ~~~~~^
/Users/runner/work/OpenTimelineIO-Swift-Bindings/OpenTimelineIO-Swift-Bindings/OpenTimelineIO/src/opentimelineio/anyDictionary.h:32:11: error: use of undeclared identifier 'map'
    using map::map;
          ^

These errors indicate that the compiler is unable to find the std::any type and the std::map type in the std:: namespace.

Potential Solution

The potential solution to this issue is to specify the C++ version in the build setup for the OTIO bindings. By explicitly specifying C++17, the compiler will be able to find the std::any type and resolve the build errors.

Specifying C++17 in the Build Setup

To specify C++17 in the build setup, you can add the following flag to the compiler command:

-c++17

This flag tells the compiler to use the C++17 standard, which includes the std::any type.

Conclusion

The OTIO submodule update stuck on the std::any C++ version issue is a problem that can be resolved by specifying the C++ version in the build setup. By adding the -c++17 flag to the compiler command, the compiler will be able to find the std::any type and resolve the build errors. This solution is likely to resolve the issue and allow the OTIO submodule update to proceed.

Recommendations

To avoid similar issues in the future, it is recommended to:

  • Specify the C++ version in the build setup for all projects that use C++17 features* Use a consistent C++ version across all projects to avoid version conflicts.
  • Regularly update the C++ standard library to ensure that the latest features are available.

By following these recommendations, you can ensure that your projects are built with the correct C++ version and avoid issues like the one described in this article.

Additional Resources

For more information on the std::any type and C++17 features, you can refer to the following resources:

Q: What is the OTIO submodule update issue?

A: The OTIO submodule update issue is a problem that occurs when updating the OpenTimelineIO (OTIO) submodule in a project. The issue is caused by a C++ version conflict, specifically with the std::any type.

Q: What is the std::any type?

A: The std::any type is a new addition to the C++ standard library, introduced in C++17. It is a type that can hold any type of value, including built-in types and user-defined types.

Q: Why is the std::any type causing issues?

A: The std::any type is causing issues because the OTIO code is not explicitly specifying the C++ version. As a result, the compiler is unable to find the std::any type in the std:: namespace, leading to build errors.

Q: What are the example build errors?

A: The example build errors are:

In file included from /Users/runner/work/OpenTimelineIO-Swift-Bindings/OpenTimelineIO-Swift-Bindings/OpenTimelineIO/src/opentimelineio/serializableObject.h:9:
/Users/runner/work/OpenTimelineIO-Swift-Bindings/OpenTimelineIO-Swift-Bindings/OpenTimelineIO/src/opentimelineio/anyDictionary.h:29:58: error: no member named 'any' in namespace 'std'
class AnyDictionary : private std::map<std::string, std::any>
                                                    ~~~~~^
/Users/runner/work/OpenTimelineIO-Swift-Bindings/OpenTimelineIO-Swift-Bindings/OpenTimelineIO/src/opentimelineio/anyDictionary.h:32:11: error: use of undeclared identifier 'map'
    using map::map;
          ^

Q: How can I resolve the issue?

A: To resolve the issue, you can specify the C++ version in the build setup for the OTIO bindings. By explicitly specifying C++17, the compiler will be able to find the std::any type and resolve the build errors.

Q: How do I specify C++17 in the build setup?

A: To specify C++17 in the build setup, you can add the following flag to the compiler command:

-c++17

This flag tells the compiler to use the C++17 standard, which includes the std::any type.

Q: What are the benefits of specifying C++17 in the build setup?

A: Specifying C++17 in the build setup has several benefits, including:

  • Resolving build errors caused by the std::any type
  • Ensuring that the compiler uses the correct C++ standard
  • Enabling the use of C++17 features in the project

Q: What are some best practices for avoiding C++ version conflicts?

A: Some best practices for avoiding C++ version conflicts include:

  • Specifying the C++ version in the build setup for all projects that use C++17 features
  • Using a consistent C++ version across all projects to avoid version conflicts
  • Regularly updating the C++ standard library to ensure that the latest features are available

Q: Where can I find more information on the std::any type and C++17 features?

A: You can find more information on the std::any type and C++17 features on the following resources:

By following these best practices and resources, you can ensure that your projects are built with the correct C++ version and avoid issues like the one described in this article.