[bug#39192] [PATCH] gnu: hexedit: Make F1 help more reliable

["Jakub Kądziołka" <kuba@kadziolka.net>]

On Tue, Jan 28, 2020 at 12:36:04AM +0100, Marius Bakke wrote:
> Jakub Kądziołka <kuba@kadziolka.net> writes:
> 
> > * gnu/packages/hexedit.scm (hexedit)[arguments](patch-man-path): New
> >   phase.
> >   [inputs]: Add MAN-DB.
> 
> While this change is harmless, I think we can generally expect "man" to
> be available.  Does the program crash if man-db is not installed?  Or
> does it print an actionable error message?
> 
> In the latter case I'm inclined to leave things as-is, in the former
> case let's patch it.  But no strong opinion, mostly curious :-)

Currently, the problem appears when hexedit is used in a `guix
environment', and man-db is not specified as an input for the
environment. In this case (assuming --pure hasn't been used), man prints
an error message saying "no manpage for hexedit" when the user presses
F1, but it cannot be seen until one exits hexedit. For a new user, this
is not a trivial feat. Moreover, the error is confusing - it suggests
that the manpage just hasn't been packaged.

When man isn't found at all, no error message is printed, the F1 key
just makes the screen blink. This could happen in a --pure environment.

In hindsight, this is something I should've explained in my first message.
Sorry about that.