On Mon, May 02, 2011 at 12:18:06AM +0000, Paul D. Smith wrote:
> CVSROOT: /sources/make
> Module name: make
> Changes by: Paul D. Smith <psmith> 11/05/02 00:18:06
>
> Modified files:
> . : ChangeLog read.c
>
> Log message:
> Avoid invoking glob() unless the filename has potential globbing
> characters in it, for performance improvements.
>
> CVSWeb URLs:
> http://cvs.savannah.gnu.org/viewcvs/make/ChangeLog?cvsroot=make&r1=2.428&r2=2.429
> http://cvs.savannah.gnu.org/viewcvs/make/read.c?cvsroot=make&r1=1.198&r2=1.199
This change seems to be breaking how $(wildcard) works for patterns
without glob characters.
For example, I used to check wheter a file exists with
ifneq ($(wildcard path/to/file),)
$(info path/to/file exists)
endif
but now this is triggering all the time, because wildcards does not see
glob characters in the pattern, decides to avoid globbing it,
and just leaves path/to/file in place.
And this seems to be going in contrary with what make's manual says:
---- 8< ----
@example
$(wildcard @var{pattern}@dots{})
@end example
@noindent
This string, used anywhere in a makefile, is replaced by a
space-separated list of names of existing files that match one of the
given file name patterns. If no existing file name matches a pattern,
then that pattern is *omitted* from the output of the @code{wildcard}
function. Note that this is different from how unmatched wildcards
behave in rules, where they are used verbatim rather than ignored
(@pxref{Wildcard Pitfall}).
---- 8< ----
(emphasis added)
This example from the manual
---- 8< ----
This one is slightly more interesting: it defines a macro to search for
the first instance of a program in @code{PATH}:
@smallexample
pathsearch = $(firstword $(wildcard $(addsuffix /$(1),$(subst :,
,$(PATH)))))
LS := $(call pathsearch,ls)
@end smallexample
---- 8< ----
is now broken too, because LS will return first directory from path + ls
regardless of whether ls is there. Try it:
---- 8< ----
PATH := /aaa/bbb:$(PATH)
pathsearch = $(firstword $(wildcard $(addsuffix /$(1),$(subst :,
,$(PATH)))))
LS := $(call pathsearch,ls)
$(info XXX $(LS))
---- 8< ----
Maybe we should turn globbing on for $(wildcard) unconditionally?
Thanks,
Kirill
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