Process substitution with heredoc works in zsh. How to make it work in bash?

I want the ability to pass a heredoc to the source command for local interpretation.
The body of the heredoc document will be injected later before calling the script, and can be multiline.

I came up with this trick, which works in zsh:

source <(<<'heredoc'
echo foo
sleep 10
echo done
heredoc
) && echo ok || echo no

it prints foo, sleeps 10 seconds, then prints done, then ok. So far, so good.

Now, the script needs to run in bash.
When I feed bash (or sh) the exact same thing, I only get ok, with no wait at all, as if the command I was providing with the heredoc was just true.

I cannot understand why, and how I can build the same behavior in bash and sh.

>Solution :

How to make it work in bash?

Remove any here documents and execute the commands. You could preserve the group.

{
   echo foo
   sleep 10
   echo done
} && echo ok || echo no

You can use, both in zsh and bash, source /dev/stdin if you want to execute commands in the current execution environment coming from a steam, like a here document. No need for <( process substitution in either case. So here you go:

source /dev/stdin <<heredoc
echo foo
sleep 10
echo done
heredoc

Note: this looks very odd thing to do and most probably there are better solutions to what you are doing.

why

Because in bash empty redirection like a here document without a command does nothing. You have to for example cat the content of the stream created by here document to output it to standard output for process substation to capture it.