Logging.disable_logging() either broken or docs not clear on usage

[IanButterworth]

From the docs on disable_logging() I believe this should be able to enable the debug logging. Either it's broken or the docs aren't clear on correct usage

julia> using Logging
julia> @debug "hello"

julia> Logging.disable_logging(Logging.BelowMinLevel)
LogLevel(-1000000)
julia> @debug "hello"

julia>

[YellowFoxH4XOR]

So first of all to see the logs in realtime use ENV["JULIA_DEBUG"] = "all"

julia> using Logging

julia> ENV["JULIA_DEBUG"] = "all"
"all"

julia> @debug "hello"
┌ Debug: hello
└ @ Main REPL[3]:1

julia> @info "hello"
[ Info: hello

julia> disable_logging(LogLevel(-1))   # **FOR INFO**
Info

julia> @info "hello"
[ Info: hello

julia> @debug "hello"

julia> disable_logging(LogLevel(-1001))  # **FOR DEBUG**
Debug

julia> @debug "hello"
┌ Debug: hello
└ @ Main REPL[9]:1

julia> @info "hello"
[ Info: hello

hope this resolves your issue 😄

[IanButterworth]

I see. So JULIA_DEBUG overrules the loglevel system for @debug.

Instead of the docstring here:

Disable all log messages at log levels equal to or less than level. This is a global 
setting, intended to make debug logging extremely cheap when disabled.

Perhaps it's more accurate to say

Disable all log messages at log levels equal to or less than level. This is a global 
setting, intended to make debug logging extremely cheap when disabled. 
Note that for `@debug` logging, the code source must be covered under `ENV["JULIA_DEBUG"]` 
i.e. `ENV["JULIA_DEBUG"] = "all"` or `ENV["JULIA_DEBUG"] = "YourPackage"` must be set

I can PR if you agree?

[IanButterworth]

I have to say I do find that setup a bit inelegant/unclear

[YellowFoxH4XOR]

`ENV["JULIA_DEBUG"] = "YourPackage" makes more sense

Also, need a clear picture of how disable_logging() affects debug, info, warn and error

[JimCircadian]

I'm keen on this change @IanButterworth. It feels quite unclear to be unable to enable debug logging during development without resorting to environment variable changes, especially when it effectively means the disable_logging becomes redundant.

julia> using Logging

julia> @info "test"
[ Info: test

julia> @debug "test"

julia> Base.disable_logging(LogLevel(-1001))
Debug

julia> @debug "test"

julia> ENV["JULIA_DEBUG"]="all"
"all"

julia> @debug "test"
┌ Debug: test
└ @ Main REPL[7]:1

EDIT: Appreciate that brute forcing all modules to log debug might be a bit naff, so also happy to look at a PR, perhaps with some addition that allows registration of the necessary modules? A enable_debug for modules imported / used, perhaps?

[IanButterworth]

A clarifying note added to #57591