Re: make -V default behavior change

[christos%zoulas.com@localhost (Christos Zoulas)]

On Jun 19,  8:18pm, joerg%bec.de@localhost (Joerg Sonnenberger) wrote:
-- Subject: Re: make -V default behavior change

| On Mon, Jun 19, 2017 at 02:02:18PM -0400, Christos Zoulas wrote:
| > On Jun 19,  7:50pm, joerg%bec.de@localhost (Joerg Sonnenberger) wrote:
| > -- Subject: Re: make -V default behavior change
| > 
| > | Again, you still don't get deterministic behavior of expanded variables.
| > 
| > Why? '-V' expands. '-dV -V' does not. And it really does not matter
| > since the unexpanded -V output is only for human consumption (debugging).
| 
| Try:
| 
| .MAKE.EXPAND_VARIABLES:= 0
| 
| BAR = 0
| FOO = ${BAR}
| 
| and ask for the value of FOO.

That prints:

    ${BAR}

same as before. Nothing changed. -V defaults to expand as it defaulted
before not to expand. -dV and .MAKE.EXPAND_VARIABLES overrides the
behavior. Yes, this is too complicated but I did not change it; it was
there committed as a result of the 2002 conversation.

| > I could do that, but then more complexity. N different ways to do the
| > same thing.
| 
| But they are *not* the same thing. Expanded vs non-expanded is very
| different.

Unexpanded is only useful for debugging; it should not be exposed as
the default behavior. It was a design or coding mistake in the first
place. Fixing it does not affect compatibility in an program-visible
from. It is only user-visible. 

| > | (3) Revert -V behavior.
| > 
| > It does not matter. If I change in my Makefile:
| > 
| > FOO=${BAR}
| > to:
| > FOO:=${BAR}
| > 
| > Should the -V output change? What does an external program expect to
| > do with ${BAR}?
| 
| Yes. I.e. figure out if the build rules support something like our PIE
| flags etc. It is even documented to do that.

>From the unexpanded variable that contains other variables internal
to the Makefiles? That can change anytime since it is not part of
the user-visible API?

| > And if I add -v to the mix, should I go and remove -dV? How about
| > .MAKE.EXPAND_VARIABLES?
| 
| -dV was useless and should be again. The only purpose it served was to
| override .MAKE.EXPAND_VARIABLES and even that could have been done by
| setting the latter directly on the command line.

No, it can't... At least it does not seem to :-)

[2:40pm] 22>cat mk
.MAKE.EXPAND_VARIABLES:=0
BAR=1
FOO=${BAR}
[2:40pm] 23>make -f mk -D.MAKE.EXPAND_VARIABLES:=1 -V FOO
${BAR}

christos