How to temporarily suppress all error and warning messages?

General Usage
1

Hi,
I want to be able to temporarily suppress all errors and warnings.
I tried doing something like this using redirect_stderr :

foo() = @warn "oh oh"

io = open("tmp.err","w")
redirect_stderr(io) do
    foo()
end
close(io)

but this didn’t seem to work, the warning message was still displayed (and also nothing was written to the tmp.err file). Am I using it wrong or misunderstanding something about stderr here?

I also tried the macros from Suppressor.jl but they don’t seem to work for this case with Julia 1.4.1.

2

Nevermind, I guess I should be just using with_logger(NullLogger()) do; foo(); end here.

2 Likes
3

As a follow up question- why is the code in the OP not capturing the warning message to the file? What kind of errors/warnings would be redirected when using redirect_stderr?

4

My guess is that maybe @warn writes to stdin instead of stderr?

5

The old stderr has already been captured by the global logger, so it will not be redirected. If you reverse the order (create the logger after redirecting) it works:

julia> using Logging

julia> io = open("stderr.txt", "w");

julia> redirect_stderr(io) do
           logger = ConsoleLogger(stderr)
           with_logger(logger) do
               @info "Hello, world."
           end
       end

julia> close(io)

julia> read("stderr.txt", String)
"[ Info: Hello, world.\n"
2 Likes
6

Thanks!