Re: Making PATH precious?

[Ralf Corsepius]

Am Mit, 2002-09-11 um 11.08 schrieb Akim Demaille:
> 
> | Akim Demaille <address@hidden> wrote:
> | > What about making PATH a precious variable?  This way, we will be able
> | > to notice when two runs are performed with different PATH.  It would
> | > also make
> | >
> | >         PATH=foo ./configure
> | >
> | > similar to
> | >
> | >         ./configure PATH=foo
> | >
> | > i.e., ./config.status --recheck will _preserve_ the value of PATH.
> | >
> | >
> | > Now the bad effect is:
> | >
> | > 1. PATH will automagically appear in Automake's Makefile.in because
> | > autoconf AC_SUBST the precious vars and all the AC_SUBST vars are
> | > automagically put in Makefile.in.
> | >
> | > 2. PATH will appear on the command line each time ./config.status
> | > --recheck is relaunched.  For instance:
Worse: 
It will duplicated each time config.status --recheck is invoked.

Even worser:
It will be duplicated each time a config-subdir configure is invoked

> | Hi Akim!
> | 
> | Also, that would keep me from rebuilding with a different PATH,
> | even when I *know* that's what I want to do, Right?
> 
> Well, yes :(  The point is more to relieve the maintainers from lost
> users, than to make _directly_ the maintainers' lives easier.
> 
> | I'm not sure it's worthwhile.
> | PATH evolves.  Inevitably, people will change it,
> | and then weeks later, come back to a working directory
> | and find that autoconf fails.
> 
> s/autoconf/configure/
> 
> | Giving a warning might be a good compromise.
> 
> Hm...  Yes, you are right.  Thanks!
Hm, no. You both are ignoring 2 facts:

1. PATH can be very long (A PATH consisting of several 100s of
characters is not seldom)

2. Autoconf currently is not able to prune duplicate "AC_ARG_VARS" from
ac_configure_args

=> Given the fact that some shells come with very resticted command line
lengths, it's only a matter of time until configure will meet these
limitations.

=> IMHO, given the currently limited implementation of handling
"precious vars" in autoconf/configure, making PATH "precious" is
prohibitive.

Ralf