[GRASS-dev] cp -r vs -R in make

Hi,

I just ran into a problem when compiling an addon on Mac OS X:

Compiling…

Installing…

cp: the -H, -L, and -P options may not be specified with the -r option.

make: *** [install] Error 1

It seems cp -r (lowercase r) is not portable, see [1]. Mac cp man page says:

Historic versions of the cp utility had a -r option. This implementation supports that option; how-ever, however, ever, its use is strongly discouraged, as it does not correctly copy special files, symbolic links, or fifo’s.

lowercase r is used on couple of places, mainly include/Make/Install.make. So my question is if anyone thinks there are some valid reasons for using lowercase r.

Thanks,

Anna

[1] http://unix.stackexchange.com/questions/18712/difference-between-cp-r-and-cp-r-copy-command

Anna Petrášová wrote:

cp: the -H, -L, and -P options may not be specified with the -r option.

make: *** [install] Error 1

It seems cp -r (lowercase r) is not portable, see [1]. Mac cp man page says:

Historic versions of the cp utility had a -r option. This implementation
supports that option; how-ever, however, ever, its use is strongly
discouraged, as it does not correctly copy special files, symbolic links,
or fifo's.

lowercase r is used on couple of places, mainly include/Make/Install.make.
So my question is if anyone thinks there are some valid reasons for using
lowercase r.

"cp" probably shouldn't be used at all.

Executable files should be installed with $(INSTALL), non-executable
files with $(INSTALL_DATA).

In either case, they should only be used to copy a rule's prerequisite
to its target (i.e. no unconditional "bulk" copies in the body of an
unrelated rule), as in:

  destination: source
    $(INSTALL_DATA) $< $@

If the number of files is large, $(wildcard ...) and $(patsubst ...)
should be used to construct a list of targets which should then be
made prerequisites of the Makefile's "default" rule, with the
installation performed by a pattern rule.

The only places "cp" is used in the actual GRASS source tree (not
including "addons") are in Install.make, the "install" targets of a
couple of other *.make files, and the "update-po" target in
locale/Makefile. None of these are part of the actual build process.

(I just removed the one in simlib; Rules.make already has a pattern
rule for installing headers).

FWIW, the "portable" solution for recursive copies has historically
been to use "tar c ... | tar x ...".

--
Glynn Clements <glynn@gclements.plus.com>

On Tue, Jan 26, 2016 at 7:28 AM, Glynn Clements <glynn@gclements.plus.com>
wrote:

Anna Petrášová wrote:

> cp: the -H, -L, and -P options may not be specified with the -r option.
>
> make: *** [install] Error 1
>
>
> It seems cp -r (lowercase r) is not portable, see [1]. Mac cp man page
says:
>
> Historic versions of the cp utility had a -r option. This implementation
> supports that option; how-ever, however, ever, its use is strongly
> discouraged, as it does not correctly copy special files, symbolic links,
> or fifo's.
>
> lowercase r is used on couple of places, mainly
include/Make/Install.make.
> So my question is if anyone thinks there are some valid reasons for using
> lowercase r.

"cp" probably shouldn't be used at all.

Executable files should be installed with $(INSTALL), non-executable
files with $(INSTALL_DATA).

In either case, they should only be used to copy a rule's prerequisite
to its target (i.e. no unconditional "bulk" copies in the body of an
unrelated rule), as in:

        destination: source
                $(INSTALL_DATA) $< $@

If the number of files is large, $(wildcard ...) and $(patsubst ...)
should be used to construct a list of targets which should then be
made prerequisites of the Makefile's "default" rule, with the
installation performed by a pattern rule.

The only places "cp" is used in the actual GRASS source tree (not
including "addons") are in Install.make, the "install" targets of a
couple of other *.make files, and the "update-po" target in
locale/Makefile. None of these are part of the actual build process.

(I just removed the one in simlib; Rules.make already has a pattern
rule for installing headers).

FWIW, the "portable" solution for recursive copies has historically
been to use "tar c ... | tar x ...".

Thanks for the information on this. However, for now, I just fixed one of
the usages in Script.make (by changing -r to -R) to be able to install the
addon, since I can't fix it properly.

Anna

--
Glynn Clements <glynn@gclements.plus.com>