Re: make: should -j affect cwd?

[Mouse <mouse%Rodents-Montreal.ORG@localhost>]

>> For every Makefile, we could decide: should the Makefile be altered,
>> or should the new make be extended to support it?

> This is [a] bad approach.  It doesn't improve anything, it only makes
> code kludgier in order to support two make dialects at the same time.
> How does it help?

jklowden already explained that: it supports Makefiles that depend on
thing we don't realize the old make does and/or don't yet have in the
new make (thus avoiding the huge pain of forcing all Makefiles we care
about to be updated at once), while not requiring that support to exist
in the new make's code forever.

As for the rest of this mail: I'm not jklowden, so this is written from
my understanding of the proposal.  I may have misunderstood things, so
what I say here may not match what jklowden had/has in mind.

An unstated but very important piece of this is that the legacy support
would be a transition measure: people would be cleaning up Makefiles
that depend on it, either fixing them to eliminate the dependency on
the old semantics or fixing new make to support whatever it is they
depend on.  Once no more Makefiles need legacy mode, the old make goes
away completely.

The alternative, really, is to continue maintaining a program that's
grown by accretion and is now full of horrors nobody understands and
nobody wants to maintain, including delicious little surprises such as
the way `.if $(VAR) == "string"' and `.if "string" == $(VAR)' have
different semantics.  (Or has that one been fixed by now?)

> I still don't see how you address immediate engineering problems in
> your proposals.  [...]  In particular, there's no phase separation in
> make language, not even between parsing and interpretation.  [...]

(a) I'm not convinced this is a problem.  You even say "it isn't
obvious if such separation is possible at all".

(b) That isn't addressed because the proposal was about how to handle
the migration, whereas that issue is an issue of what to migrate to.

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