Configuration

Configuration

Using Revise by default

If you like Revise, you can ensure that every Julia session uses it by adding the following to your .julia/config/startup.jl file:

atreplinit() do repl
    try
        @eval using Revise
        @async Revise.wait_steal_repl_backend()
    catch
    end
end

If you want Revise to launch automatically within IJulia, then you should also create a .julia/config/startup_ijulia.jl file with the contents

try
    @eval using Revise
catch
end

System configuration

Linux-specific configuration

Revise needs to be notified by your filesystem about changes to your code, which means that the files that define your modules need to be watched for updates. Some systems impose limits on the number of files and directories that can be watched simultaneously; if this limit is hit, on Linux this can result in a fairly cryptic error like

ERROR: start_watching (File Monitor): no space left on device (ENOSPC)

The cure is to increase the number of files that can be watched, by executing

echo 65536 | sudo tee -a /proc/sys/fs/inotify/max_user_watches

at the Linux prompt. (The maximum value is 524288, which will allocate half a gigabyte of RAM to file-watching). For more information see issue #26.

Changing the value this way may not last through the next reboot, but you can also change it permanently.

Configuration options

Revise can be configured by setting environment variables. These variables have to be set before you execute using Revise, because these environment variables are parsed only during execution of Revise's __init__ function.

There are several ways to set these environment variables:

The function of specific environment variables is described below.

Manual revision: JULIA_REVISE

By default, Revise processes any modified source files every time you enter a command at the REPL. However, there might be times where you'd prefer to exert manual control over the timing of revisions. Revise looks for an environment variable JULIA_REVISE, and if it is set to anything other than "auto" it will require that you manually call revise() to update code.

Alternatively, you can omit the call to Revise.async_steal_repl_backend() from your startup.jl file (see Using Revise by default).

Polling and NFS-mounted code directories: JULIA_REVISE_POLL

Revise works by scanning your filesystem for changes to the files that define your code. Different operating systems and file systems offer differing levels of support for this feature. Because NFS doesn't support inotify, if your code is stored on an NFS-mounted volume you should force Revise to use polling: Revise will periodically (every 5s) scan the modification times of each dependent file. You turn on polling by setting the environment variable JULIA_REVISE_POLL to the string "1" (e.g., JULIA_REVISE_POLL=1 in a bash script).

If you're using polling, you may have to wait several seconds before changes take effect. Consequently polling is not recommended unless you have no other alternative.

User scripts: JULIA_REVISE_INCLUDE

By default, Revise only tracks files that have been required as a consequence of a using or import statement; files loaded by include are not tracked, unless you explicitly use Revise.track(filename). However, you can turn on automatic tracking by setting the environment variable JULIA_REVISE_INCLUDE to the string "1" (e.g., JULIA_REVISE_INCLUDE=1 in a bash script).

Fixing a broken or partially-working installation

During certain types of usage you might receive messages like

Warning: /some/system/path/stdlib/v1.0/SHA/src is not an existing directory, Revise is not watching

and this indicates that some of Revise's functionality is broken.

Revise's test suite covers a broad swath of functionality, and so if something is broken a good first start towards resolving the problem is to run pkg> test Revise. Note that some test failures may not really matter to you personally: if, for example, you don't plan on hacking on Julia's compiler then you may not be concerned about failures related to Revise.track(Core.Compiler). However, because Revise is used by Rebugger and it is common to step into Base methods while debugging, there may be more cases than you might otherwise expect in which you might wish for Revise's more "advanced" functionality.

In the majority of cases, failures come down to Revise having trouble locating source code on your drive. This problem should be fixable, because Revise includes functionality to update its links to source files, as long as it knows what to do.

Here are some possible test warnings and errors, and steps you might take to fix them: