Re: [PATCH] makefile: hide stderr of curl-config test

[Junio C Hamano <gitster@pobox.com>]

Paul Gortmaker <paul.gortmaker@windriver.com> writes:

> Currently, if you don't have curl installed, you will get
>
>     $ make distclean 2>&1 | grep curl
>     /bin/sh: curl-config: not found
>     /bin/sh: curl-config: not found
>     /bin/sh: curl-config: not found
>     /bin/sh: curl-config: not found
>     /bin/sh: curl-config: not found
>     $
>
> The intent is not to alarm the user, but just to test if there is
> a new enough curl installed.  However, if you look at search engine
> suggested completions, the above "error" messages are confusing
> people into thinking curl is a hard requirement.

Good observation and identification of an issue to tackle.  But why
isn't the patch like this?

 	PROGRAMS += $(REMOTE_CURL_NAMES)
-	curl_check := $(shell (echo 070908; curl-config --vernum) | sort -r | sed -ne 2p)
+	curl_check := $(shell (echo 070908; curl-config --vernum) 2>/dev/null | sort -r | sed -ne 2p)
 	ifeq "$(curl_check)" "070908"

Removal of the "reject old libcURL" is logically a separate thing
regardless of the "alarming output from make", and it probably is
better done as a separate step in a two-patch series.  Doing things
that way, when somebody objects to this:

> It wants to ensure curl is newer than 070908.  The oldest
> machine I could find (RHEL 4.6) is 2007 vintage according
> to /proc/version data, and it has curl 070C01.

saying that their installation still cares about older libcURL, we
can still keep the "remove alarming output from make" bit.

>
> The failure here is to mask stderr in the test.  However, since
> the chance of curl being installed, but too old is essentially
> nil, lets just check for existence and drop the ancient version
> threshold check, if for no other reason, than to simplifly the
> parsing of what the makefile is trying to do by humans.
>
> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
>
> diff --git a/Makefile b/Makefile
> index 9bc5e40..56f55f6 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -1573,8 +1573,8 @@ else
>  	REMOTE_CURL_NAMES = $(REMOTE_CURL_PRIMARY) $(REMOTE_CURL_ALIASES)
>  	PROGRAM_OBJS += http-fetch.o
>  	PROGRAMS += $(REMOTE_CURL_NAMES)
> -	curl_check := $(shell (echo 070908; curl-config --vernum) | sort -r | sed -ne 2p)
> -	ifeq "$(curl_check)" "070908"
> +	curl_check := $(shell curl-config --vernum 2>/dev/null)
> +	ifneq "$(curl_check)" ""
>  		ifndef NO_EXPAT
>  			PROGRAM_OBJS += http-push.o
>  		endif