redirect_stderr() and redirect_stdout() do not control logging output

[ghost]

redirect_stderr()
redirect_stdout()
@warn "should not be able to see it"

The output is

┌ Warning: should not be able to see it
└ @ Main t.jl:3

Expected no output.

[ghost]

And @info goes into stderr instead of expected stdout, not able to control it too.

[ghost]

Makes debugging harder, see timholy/Revise.jl#80

[stevengj]

I think the problem is that SimpleLogger (the default logger) stores stderr as its stream::IO member, so it keeps a reference to the original stderr stream even when the stderr global has been redirected.

[staticfloat]

Not just SimpleLogger; ConsoleLogger does as well. @c42f what, in your opinion, is the best way to change streams out from underneath a logger? Should we destroy the current loggers and create new ones that point to the streams we like?

[maleadt]

It's what we do in the atexit hook:

julia/stdlib/Logging/src/Logging.jl

Lines 55 to 63 in 665b1de

	function __init__()
	global_logger(ConsoleLogger(stderr))
	atexit() do
	logger = global_logger()
	if isa(logger, ConsoleLogger)
	global_logger(ConsoleLogger(Core.stderr, min_enabled_level(logger)))
	end
	end
	end