Inline logging output of fmtquill::join() outputs wrong data

[YuukiHogo]

In multithreaded environment the code below outputs random hex string:

std::vector<uint8_t> data(100);
LOG_DEBUG(quill::get_logger(), "data: {:02x}", fmtquill::join(data, ""));

Workaround:

std::vector<uint8_t> data(100);
auto aux = fmtquill::format("{:x02}",  fmtquill::join(data, ""));
LOG_DEBUG(quill::get_logger(), "data: {}", aux);

Is there a better way to fix this?

[odygrd]

The problem seems to be that fmt join returns a view

if you try this it will fail with error 'passing views as lvalues is disallowed'

  std::vector<uint8_t> data(100);
  auto s = fmtquill::join(data, "");
  fmtquill::format("data: {:02x}", s);

The logger makes a copy of the view and then the backend thread tries to format it.

I am not sure if that can be supported. It would be good tho to fail with a static assertion when a view is passed to a LOG macro

Your workaround is good with the only drawback that the format is done on the hot thread but i dont think we have another option here

[odygrd]

This is now disabled in compile time with 4cc4dae

As you mentioned please use the provided workaround for now

std::vector<uint8_t> data(100);
auto aux = fmtquill::format("{:x02}",  fmtquill::join(data, ""));
LOG_DEBUG(quill::get_logger(), "data: {}", aux);