Re: Bug in version 20170322: certain functions in the Bash environment break invocation of env_parallel on macOS 10.12.4

[Ole Tange]

On Sat, Apr 15, 2017 at 3:06 PM, Michael Klement
<michael.klement@usa.net> wrote:

> I'm aware of that workaround, but I thought you'd want to know that
> env_parallel is not fully robust and fails in obscure ways.
> Is env_parallel deprecated? The man page doesn't seem to say so.

env_parallel is pretty new and thus not the same production quality as parallel.

> 2017-04-14 20:53 GMT+02:00 Michael Klement <michael.klement@usa.net>:
:
>> v3.2.57: only stderr output:
>>
>> -bash: /usr/bin/which: Argument list too long
>> -bash: -n: command not found

Given your attached file, you are most likely being hit by the
environment being too big:

>From man env_parallel:

   Environment space
      By default env_parallel will export all environment
      variables, arrays, aliases, functions and shell options
      (see details for the individual shells below).

      But this only works if the size of the current environment
      is smaller than the maximal length of a command and
      smaller than half of the max if running remotely. E.g. The
      max size of Bash's command is 128 KB, so env_parallel will
      fail if set | wc -c is bigger than 128 KB. Technically the
      limit is in execve(1) which IPC::open3 uses.

      Bash completion functions are well-known for taking up
      well over 128 KB of environment space and the primary
      reason for causing env_parallel to fail.

      Instead you can use --env to specify which variables,
      arrays, aliases and functions to export as this will only
      export those with the given name.

And earlier:

      Due to the problem with environment space (see below)
      the recommended usage is:

        # Run once to record the "empty" environment
        env_parallel --record-env
        alias myalias=echo
        myvar=it
        myfunc() { myalias $1 $myvar works.; }

        # Use --env _ to only transfer the names not in the "empty" environment
        env_parallel --env _ -S localhost myfunc ::: Yay,

But even tough it is documented your bug report is valuable:
env_parallel should detect this error and give you a sensible error
message instead.

As the above is the recommended usage, maybe --env _ should be default
if ~/.parallel/ignored-vars exist?


/Ole