Re: [Qemu-devel] [PATCH 2/2] Makefile: Derive "PKGVERSION" from "git describe" by default

[Eric Blake <eblake@redhat.com>]

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On 05/31/2016 07:31 PM, Fam Zheng wrote:
> Currently, if not specified in "./configure", QEMU_PKGVERSION will be
> empty. Write a rule in Makefile to generate a value from "git describe"
> combined with a possible git tree cleanness suffix, and write into a new
> header.
> 
>     $ cat qemu-version.h
>     #define QEMU_PKGVERSION "-v2.6.0-557-gd6550e9-unclean"
> 
> Include the header in .c files where the macro is referenced. It's not
> necessary to include it in all files, otherwise each time the content of
> the file changes, all sources have to be recompiled.
> 
> Signed-off-by: Fam Zheng <famz@redhat.com>
> ---

> +qemu-version.h: FORCE
> +	$(call quiet-command, \
> +		(cd $(SRC_PATH); \

Can CDPATH interfere with this one?

> +		echo -n '#define QEMU_PKGVERSION '; \

'echo -n' is non-portable, use printf instead.

> +		if test -n "$(PKGVERSION)"; then \
> +			echo '"$(PKGVERSION)"'; \
> +		else \
> +			echo -n '"-'; \

And again

> +			if ! git status &>/dev/null; then \
> +				echo -n "no-git"; \

and again

> +			else \
> +				git describe 2>/dev/null | tr -d '\n'; \
> +				if ! git diff-index --quiet HEAD &>/dev/null; then \
> +					echo -n '-unclean'; \

and again

Why -unclean instead of -dirty?

> +				fi \
> +			fi; \
> +			echo '"'; \
> +		fi) > $@.tmp)
> +	$(call quiet-command, cmp --quiet $@ $@.tmp || mv $@.tmp $@)
> +


-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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