Re: [PATCH 2/8] Documentation/Makefile: conditionally include ../GIT-VERSION-FILE

[Jeff King <peff@peff.net>]

On Fri, Nov 06, 2020 at 07:38:06PM +0000, Ramsay Jones wrote:

> I hadn't done so yet, but I had planned to modify the GIT-VERSION-GEN script
> (with -v parameter, say) to just output the version to stdout, because it
> would save a sed invocation. It currently looks something like this:
> 
>   diff --git a/Makefile b/Makefile
>   index 372139f1f2..f166fbe067 100644
>   --- a/Makefile
>   +++ b/Makefile
>   @@ -493,7 +493,11 @@ all::
>  
>    GIT-VERSION-FILE: FORCE
>           @$(SHELL_PATH) ./GIT-VERSION-GEN
>   --include GIT-VERSION-FILE
>   +
>   +ifeq ($(wildcard GIT-VERSION-FILE),)
>   +$(shell ./GIT-VERSION-GEN)
>   +endif
>   +GIT_VERSION = $(eval GIT_VERSION := $$(shell cat GIT-VERSION-FILE | sed -e 's/^GIT_VERSION = //'))$(GIT_VERSION)

Yeah, not too surprising. If we grow a lot of these fill-in-the-value
stubs, it might be worth abstracting it out into a function (using
$(call) should be OK, as even Apple's ancient version of GNU make has
it).

I do think the one that evals an "include" might end up being more
readable and flexible, though. I'm not sure if the include needs to be
more aggressive about using ":=" though (in a simple test it didn't seem
to be, and since we'll be filling in a concrete value that's OK to
evaluate multiple times, I think it would be OK).

> Ignore the 'ifeq' for now (I had several versions, including getting rid
> of the GIT-VERSION-FILE rule, but that caused problems without changing
> the Documentation/Makefile, and several others ... (including in contrib)).

Yeah, I didn't look at all at what complications we might get from other
Makefiles. Though if everything is literally running `GIT-VERSION-GEN`
directly then I think they could all use the same code.

> So, I haven't worked everything out yet, but I had planned to look at
> this next.

Sounds good. I mostly wanted to plant the seed in your head. Finding
that it was already growing is better still. :)

-Peff