Re: texi2html: problems with srcdir != builddir

[Ralf Wildenhues]

Hello Werner,

Werner LEMBERG <wl <at> gnu.org> writes:
> 
> If srcdir != builddir, the file `texi2html.info' is erroneously
> created in srcdir.  IMHO, this shouldn't happen even if building from
> the CVS.

Not a bug, but a (long-discussed long ago, changed over time) feature.
For reference, below I quote a longer comment that is part of the
'automake' script.

Hope that helps.  Please Cc: me on replies.

Cheers,
Ralf

 Until Automake 1.6.3, .info files were built in the
 source tree.  This was an obstacle to the support of
 non-distributed .info files, and non-distributed .texi
 files.

 * Non-distributed .texi files is important in some packages
   where .texi files are built at make time, probably using
   other binaries built in the package itself, maybe using
   tools or information found on the build host.  Because
   these files are not distributed they are always rebuilt
   at make time; they should therefore not lie in the source
   directory.  One plan was to support this using
   nodist_info_TEXINFOS or something similar.  (Doing this
   requires some sanity checks.  For instance Automake should
   not allow:
      dist_info_TEXINFOS = foo.texi
      nodist_foo_TEXINFOS = included.texi
   because a distributed file should never depend on a
   non-distributed file.)

 * If .texi files are not distributed, then .info files should
   not be distributed either.  There are also cases where one
   wants to distribute .texi files, but does not want to
   distribute the .info files.  For instance the Texinfo package
   distributes the tool used to build these files; it would
   be a waste of space to distribute them.  It's not clear
   which syntax we should use to indicate that .info files should
   not be distributed.  Akim Demaille suggested that eventually
   we switch to a new syntax:
   |  Maybe we should take some inspiration from what's already
   |  done in the rest of Automake.  Maybe there is too much
   |  syntactic sugar here, and you want
   |     nodist_INFO = bar.info
   |     dist_bar_info_SOURCES = bar.texi
   |     bar_texi_DEPENDENCIES = foo.texi
   |  with a bit of magic to have bar.info represent the whole
   |  bar*info set.  That's a lot more verbose that the current
   |  situation, but it is # not new, hence the user has less
   |  to learn.
          |
   |  But there is still too much room for meaningless specs:
   |     nodist_INFO = bar.info
   |     dist_bar_info_SOURCES = bar.texi
   |     dist_PS = bar.ps something-written-by-hand.ps
   |     nodist_bar_ps_SOURCES = bar.texi
   |     bar_texi_DEPENDENCIES = foo.texi
   |  here bar.texi is dist_ in line 2, and nodist_ in 4.

 Back to the point, it should be clear that in order to support
 non-distributed .info files, we need to build them in the
 build tree, not in the source tree (non-distributed .texi
 files are less of a problem, because we do not output build
 rules for them).  In Automake 1.7 .info build rules have been
 largely cleaned up so that .info files get always build in the
 build tree, even when distributed.  The idea was that
   (1) if during a VPATH build the .info file was found to be
       absent or out-of-date (in the source tree or in the
       build tree), Make would rebuild it in the build tree.
       If an up-to-date source-tree of the .info file existed,
       make would not rebuild it in the build tree.
   (2) having two copies of .info files, one in the source tree
       and one (newer) in the build tree is not a problem
       because `make dist' always pick files in the build tree
       first.
 However it turned out the be a bad idea for several reasons:
   * Tru64, OpenBSD, and FreeBSD (not NetBSD) Make do not behave
     like GNU Make on point (1) above.  These implementations
     of Make would always rebuild .info files in the build
     tree, even if such files were up to date in the source
     tree.  Consequently, it was impossible to perform a VPATH
     build of a package containing Texinfo files using these
     Make implementations.
     (Refer to the Autoconf Manual, section "Limitation of
     Make", paragraph "VPATH", item "target lookup", for
     an account of the differences between these
     implementations.)
   * The GNU Coding Standards require these files to be built
     in the source-tree (when they are distributed, that is).
   * Keeping a fresher copy of distributed files in the
     build tree can be annoying during development because
     - if the files is kept under CVS, you really want it
       to be updated in the source tree
     - it is confusing that `make distclean' does not erase
       all files in the build tree.

 Consequently, starting with Automake 1.8, .info files are
 built in the source tree again.  Because we still plan to
 support non-distributed .info files at some point, we
 have a single variable ($INSRC) that controls whether
 the current .info file must be built in the source tree
 or in the build tree.  Actually this variable is switched
 off for .info files that appear to be cleaned; this is
 for backward compatibility with package such as Texinfo,
 which do things like
   info_TEXINFOS = texinfo.txi info-stnd.texi info.texi
   DISTCLEANFILES = texinfo texinfo-* info*.info*
   # Do not create info files for distribution.
   dist-info:
 in order not to distribute .info files.