Bug#430649: Please clarify splitting/syntax of DEB_BUILD_OPTIONS
On Wed, Jul 04, 2007, Russ Allbery wrote:
> At first glance, using a space-separated list of options would be a lot
> easier to parse since you could parse it entirely with internal make
> functions and not have to shell out to run sed.
A couple of updates:
- parsing a comma-separated list wouldn't require sed as shown in
#209008 with this Make snippet to convert comma-separated to
, := ,
DEB_BUILD_OPTIONS := $(subst $(,), ,$(DEB_BUILD_OPTIONS))
- separating with commas prevents passing options with commas; a sample
use case which might be useful in the near future could be passing
CFLAGS/LDFLAGS via DEB_BUILD_OPTIONS, and some of these flags require
commas to reach the linker/assembler/preprocessor (e.g. "-Wl,-O1")
Note: there's an interesting issue in that CFLAGS or LDFLAGS are
typically space separated and hence we would need to define how to pass
multiple such flags in DEB_BUILD_OPTIONS...
It seems to me that the more separators we allow, the less room for
future expansion of DEB_BUILD_OPTIONS we keep and the more complex the
early parsing of DEB_BUILD_OPTIONS will be.
Additionally to the request to document the syntax and remove the
recommendation for "findstring", I also wish Policy would document how
to deal with a keyword being present multiple times. For example:
DEB_BUILD_OPTIONS="noopt parallel=2 debug parallel=1"
On this particular subject, I would recommend that Policy requires to
parse DEB_BUILD_OPTIONS from left to right and to override any previous
parameter when its met a second time (latest definition wins).
Perhaps it makes sense to explicitely mention "=" in parameters and
the allowed chars in parameter names; I could imagine we could at some
point support "+=":
DEB_BUILD_OPTIONS="CFLAGS=-Os parallel=2 debug CFLAGS+=-g"
(The += words could be parsed in Make using eval for example.)