Re: [PATCH] Makefile: check that tcl/tk is installed

[Jonathan Nieder <jrnieder@gmail.com>]

Hi,

Christian Couder wrote:

> By default running `make install` in the root directory of the
> project will set TCLTK_PATH to `wish` and then go into the "git-gui"
> and "gitk-git" sub-directories to build and install these 2
> sub-projects.
>
> When Tcl/Tk is not installed, the above will succeed if gettext
> is installed, as Tcl/Tk is only required as a substitute for msgfmt
> when msgfmt is not installed. But then running the installed gitk
> and git-gui will fail.

Hm, I am not sure I understand the point of this change.  E.g.
if I run "make install" for git and install tk later, wouldn't I
want gitk to work?

Can you say more about where this comes up? gitk is a wrapper
script

	#!/bin/sh
	# Tcl ignores the next line -*- tcl -*- \
	exec wish "$0" -- "$@"

Would some error handling there help?  E.g. something like

	#!/bin/sh
	# Tcl ignores the next line -*- tcl -*- \
	exec wish "$0" -- "$@" || \
	{ echo >&2 "Cannot run gitk without tk"; exit 127; }

> If neither Tcl/Tk nor gettext are installed, then processing po
> files will fail in the git-gui directory. The error message when
> this happens is very confusing to new comers as it is difficult
> to understand that we tried to use Tcl/Tk as a substitute for
> msgfmt, and that the solution is to either install gettext or
> Tcl/Tk, or to set both NO_GETTEXT and NO_TCLTK.

Hm, is this the motivating problem?  This is a condition where
the rationale for failing the build seems clearer.

> To improve the current behavior when Tcl/Tk is not installed,
> let's just check that TCLTK_PATH points to something and error
> out right away if this is not the case.

At first glance I had thought this might set NO_TCLTK automatically,
which I think would be problematic for the reasons mentioned above.

Erroring out like this patch does and asking the user to explicitly
confirm that they want to install gitk without Tcl/Tk is less
problematic, so I am not *against* this patch, just interested in more
background.

Thanks and hope that helps,
Jonathan