void_one

please reply to this comment with a link once they implement Doom in Jira

It is a good point that behave_differently.sh does not necessary run its argument program, but can analyze it in another way. (The context of Bash scripts suggests execution but that is a misleading hint.)

In the broader formulation behave_differently.sh tells that its argument program terminates and produces finite input, which is a halting problem.

Bot the very approach is fun:

  class RusselSet(set):
      def __contains__(self, other):
          return other not in other

  paradox = RusselSet()

  paradox in paradox  # ?

yes, and then behave_differently.sh runs it to capture and modify its output, but without any arguments

There is a fallacy in constructing "paradox.sh" problem.

"behave_differently.sh" requires an argument, a program to be run and produce some output. If "behave_differently.sh" is run without any argument, then there is no specified correct behavior.

Thus, "paradox.sh" also requires "$1" to be non-empty, otherwise it's result is undefined. When invoking "./paradox.sh ./paradox.sh", the inner "paradox.sh" will be launched without any arguments, running "behave_differently.sh" also without arguments.

There is no logical impossibility, just constructed way to trigger unspecified behavior in "behave_differently.sh".

PSF people silently hide docs on older Python versions from the search indexes. That will make it harder to support apps developed on those older versions. In general, looks evil, are there maybe any good reasons for such a step?