Re: distclean-recursive broken?

[Alexandre Duret-Lutz]

[I've s/CONFIG_SUBDIRS/DIST_SUBDIRS/ your mail for clarity;
there is no CONFIG_SUBDIRS variable.  Maybe that's where the
confusion comes from?  DIST_SUBDIRS is not related to
AC_CONFIG_SUBDIRS.]

>>> "Ralf" == Ralf Corsepius <address@hidden> writes:

 Ralf> On Sun, 2004-02-15 at 22:28, Alexandre Duret-Lutz wrote:
 >> >>> "Ralf" == Ralf Corsepius <address@hidden> writes:
 >> 
 >> [...]
 >> 
 Ralf> SUBDIRS = sub1 @moresubdirs@
 Ralf> DIST_SUBDIRS = sub1
 >> >> 
 >> >> Unfortunately we do not support such setup.  Right now
 >> >> $(SUBDIRS) must always be a subset of $(DIST_SUBDIRS).
 Ralf> The example below proves the contrary.
 >> 
 >> Additionally each directory listed in DIST_SUBDIRS or SUBDIRS
 >> should always have a Makefile.

 Ralf> I think you are missing the point: I am running "make distcheck". 

I confess I fail to see why this is relevant.  distcheck just
runs some ordinary commands a user may want to run.

    ./configure [any option]
    make dist
    make distclean

is a legitimate user sequence. `make dist' should distribute all
directories (all those listed in DIST_SUBDIRS, not only the
subset to built with `make all' which is listed in SUBDIRS),
this implies that `make dist' must recurse into these
directories, hence ./configure must have created a Makefile in
all of them unconditionally.  Since there is a Makefile in these
distributed but otherwise not built directories, distclean must
recurse into them to clean them.

If you want to convince yourself, look at test/subconf3.test
(this is the example from the manual), and edit
lib/am/subdirs.am so distclean recurses only in SUBDIRS, not
DIST_SUBDIRS.  This ought to cause the test to fail because
opt/Makefile is not cleaned.

 Ralf> "make distcheck" first recurses into SUBDIRS, but afterwards recurses
 Ralf> into DIST_SUBDIRS on the "make distclean-recursive".

To remove the Makefile that each DIST_SUBDIRS directory must have.

 Ralf> Without any doubt, this behavior is broken: "make distcheck" must run
 Ralf> distclean-recursive on *same set* of directories it ran configure
 Ralf> beforehand - ATM, it doesn't. 

If there is a directory `make distclean' must not recurse into
because there is no Makefile, then `make dist' cannot recurse
into this directory either, hence this directory must not be
listed in DIST_SUBDIRS.

Or to explain it in the other way: DIST_SUBDIRS contains the
directories `make dist' must recurse into.  Since `make dist'
must recurse in these directories, they must have a Makefile
(i.e. be configured).  Since they have a Makefile `make
distclean' must also recurse into them to remove it.

DIST_SUBDIRS is tied to `make dist', not to AC_CONFIG_SUBDIRS.

Sure, you could fix your problem this by conditionally omitting
unconfigured directories from DIST_SUBDIRS and SUBDIRS.  But the
consequence is that these directories would not always be
distributed.  (`make dist' would be complete only in some kind
of "full" configuration.)  I know some people do DIST_SUBDIRS =
$(SUBDIRS), precisely to support conditional AC_CONFIG_SUBDIRS.
I do not recommend it because it's then easy to make incomplete
distributions by mistake.  Maybe one can combine this with a
conditional dist-hook and be safe.

[...]

 Ralf> This also matches with autoconf.info:
 Ralf> ------
 Ralf> However `make dist' should always recurse into both `src/' and
 Ralf> `opt/'.  Because `opt/' should be distributed even if it is not needed
 Ralf> in the current configuration. This means `opt/Makefile' should be
 Ralf> created unconditionally.  (1)
 Ralf> ------

The intent of this paragraph is to explain why although it will
be possible to omit some directories from SUBDIRS (so they are
not built) they should always be 1) configured unconditionally
and 2) listed in DIST_SUBDIRS, so that `make dist' distributes
them.  The footnote should also put more emphasis on
"unconditionally".

The SUBDIRS/DIST_SUBDIRS distinction is introduced in the
following paragraphs.  This one just prepares the reader to it.

 >> I see pretty well that you want conditional AC_DIST_SUBDIRS.
 Ralf> IMO, one reason for not having them is design of "make distcheck".

Unfortunately I still don't see why this is a problem specific
to `make distcheck' :(  Any suggestion?

 >> The SUBDIRS/DIST_SUBDIRS
 >> distinction is not meant to solve this problem.
 Ralf> I disagree - It does.

 Ralf> As the citation from automake.info says, the set of SUBDIRS to be
 Ralf> recursed by "make dist" must match the default set of SUBDIRS to be
 Ralf> recursed into.

I'm really surprised you read it this way.  Maybe it helps to
quote the previous paragraphs too:

|    To illustrate how this works, let's assume we have two directories
| `src/' and `opt/'.  `src/' should always be built, but we want to
| decide in `./configure' whether `opt/' will be built or not.  (For this
| example we will assume that `opt/' should be built when the variable
| `$want_opt' was set to `yes'.)
| 
|    Running `make' should thus recurse into `src/' always, and then
| maybe in `opt/'.
| 
|    However `make dist' should always recurse into both `src/' and
| `opt/'.  Because `opt/' should be distributed even if it is not needed
| in the current configuration. This means `opt/Makefile' should be
| created unconditionally.  (1)

This means that `make dist' will recurse in *more* directories
than `make'.  That's the whole point of this entire section and
of the DIST_SUBDIRS/SUBDIRS distinction.

Is it clearer now?  Any suggestion how to word this more
clearly?
-- 
Alexandre Duret-Lutz