bug#9859: subdir-objects, dirstamps and --disable-dependency-tracking

[Stefano Lattarini]

Hello automakers.

The recent commit `v1.11-512-g40c3432', required to fix automake bugs #8485

and #8526, has re-introduced the bug reported by Ignacy Gawedzki in his

message "subdir-objects, dirstamps and --disable-dependency-tracking (bug?)",

posted to the automake list in March 2011. I'm thus registering this

bug in the automake tracker so that we won't forget about it.

Regards,

Stefano

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Reference:

<http://lists.gnu.org/archive/html/automake/2011-03/msg00124.html>

a.k.a.:

<http://thread.gmane.org/gmane.comp.sysutils.automake.general/12768>

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Original message follows ...

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Hi,

I suspect I found a bug in automake 1.11.1 .

I have a project in which some program has .ll and .yy sources that must be

generated by flex and bison. It also happens I need to have specific

preprocessor options passed to that program using a _CPPFLAGS variable. This

makes everything produced for that program prefixed with the program name.

Besides, I need to use the subdir-objects automake option.

Now the problem is that some subdirectories are not created automatically in

$(builddir) as expected and I think I have found why. It happens when

configure is called with --disable-dependency-tracking, as is usually the case

when called through debhelper.

In the attached tarball, there is a minimal setup illustrating the problem.

Try to configure and build the project in a separate build directory and you

should be able to observe how automake fails to create $(builddir)/src before

calling ylwrap to generate src/bug-scanner.cc .

The Makefile has the following rule (number 1):

src/bug-scanner.$(OBJEXT): src/$(am__dirstamp) \

src/$(DEPDIR)/$(am__dirstamp)

But the bug_CPPFLAGS line in Makefile.am ultimately leads to the production of

the following rule (number 2):

src/bug-scanner.o: src/scanner.cc

...

Whereas there is *no* rule of the kind :

src/scanner.cc: src/$(am__dirstamp)

...

This looks like src/scanner.cc gets regenerated *before* src/$(am_dirstamp)

gets a chance to be considered, supposedly because of the explicit rule number

2.

Does anybody know of a clean fix/workaround?

Thanks.

Ignacy

automake-dirstamp-bug.tar.gz
Description: application/compressed-tar