Linking error when building with new 3.21.1 version

[StavrosMar]

What version of protobuf and what language are you using?
Version: main/v3.21.1
Language: C++

What operating system (Linux, Windows, ...) and version?
MacOS 11.4

What runtime / compiler are you using (e.g., python version or gcc version)
Apple clang version 12.0.5 (clang-1205.0.22.11)

What did you do?
Steps to reproduce the behavior:

1. Donwloaded 3.21.1 all version
2. Followed the instructions on the README (like I had done before for 3.18.1-rc2)
3. Regenerated the .cc and .h with the new protoc.
4. Recompiled project with updated cc files.
5. There is a linkage issue where it is unable to find the ~InternalMetadata destructor that has been moved out to a separate message_lite.cc file in 3.21.1 vs in 3.18.1-rc2 it was defined fully inside the .h class file. Please note this is the only error.
6. Repeated the same procedure for the proto example on the google website i.e. addresbook and I get exactly the same error.
7. Reverted back to 3.18.1-rc2 everything compiles fine without issues.

What did you expect to see
No Linkage issue should happen

What did you see instead?
Linkage issue when building the C++ project with CMake.

[acozzette]

@StavrosMar I think the likely problem is that you rebuilt your generated code with the new protoc but did not upgrade libprotobuf (or libprotobuf-lite). For C++ the protoc version must exactly match the libprotobuf version as we don't support mixing different versions this way.

[StavrosMar]

@acozzette when running nm on the libprotobuff under /usr/local/lib I can see that the InternalMetadata objects are in there. The CMake is using the library under /usr/local/lib, I am thinking to just move the code manually inside the message_lite.h and problem should be solved, what do you think ?

[acozzette]

Actually from looking more closely I believe this has to do with mixing optimized and unoptimized code. The decision of whether to put this destructor in the header or .cc file is determined by the NDEBUG macro, so it's important for NDEBUG to be defined (or undefined) consistently across libprotobuf and the application code. There is more information about this in #9947.

[StavrosMar]

Thank you , I will set it on my cmake and see if it works , I will close the issue