Link problem w/ BUILD=Release if MESSAGE() with std::string/ostream-operator is used

[jenisys]

Description

A linker occurs in BUILD=Release if a test case uses the MESSAGE() macro together with a std::string parameter and the stream-operator. The same test program compiles without problems with BUILD=Debug.

HINT: A #include <iostream> fixes the problem in BUILD=Release.

Steps to reproduce

// -- FILES: test_syndrome.cpp
// #define FIX_RELEASE_SYNDROME_LINKER_PROBLEM  0
// #define FIX_RELEASE_SYNDROME_LINKER_PROBLEM  1  // FIXES LINKER-PROBLEM
#include "doctest/doctest.h"
#  include <string>
#if FIX_RELEASE_SYNDROME_LINKER_PROBLEM
#  include <iostream>
#endif

namespace {

// -- SYNDROME in BUILD=Release:
// MESSAGE w/ stream-operator causes link-problem if #include <iostream> is missing
TEST_CASE("Use MESSAGE w/ ostream-operator (std::string, RELEASE-SYNDROME)")
{
    const std::string name{"Alice"};
    MESSAGE("Hello "<< name);
}

} //< NAMESPACE-END

Extra information

• doctest version: v2.3.5 (and current HEAD of master and before ...)
• Operating System: macOS 10.14
• Compiler+version: Apple Clang v10.0.1

[onqtam]

Thanks for the report! This is actually a duplicate: #126
I tried solving it a few times before... I suggest you use the workaround of including <iostream> for now - I hope I get back to trying to fix this in a month or two...

There is an open PR for this: #314 - the idea behind the PR is to include <ostream> when DOCTEST_CONFIG_USE_STD_HEADERS is defined... I'm still not sure how to continue forward with this.

[jenisys]

Ok, thanks for the info.