Re: fix AC_CONFIG_LINKS([X:X]) (was: New module gnu-make)

[Ralf Wildenhues]

<http://lists.gnu.org/archive/html/automake-patches/2008-03/msg00018.html>

* Ralf Wildenhues wrote on Sat, Mar 15, 2008 at 06:28:40PM CET:
> > 
> > Current Autoconf allows you to do this:
> >   AC_CONFIG_LINKS([GNUmakefile:GNUmakefile])
> > 
> > the only bit that's missing is that automake shouldn't remove
> > the original file upon
> >   make distclean
> > 
> > in a non-VPATH build.  Will fix.
> 
> Here's a patch for automake, review appreciated.  I'll probably apply in
> a couple of days, still wondering whether also to branch-1-10.
> 
> Does anybody know a better name for CONFIG_CLEAN_VPATH_FILES (files
> which are to be removed from the build tree, but only if the build tree
> does not coincide with the source tree)?

Apparently not.  And sorry for the huge delay, I've pushed this now.
I've changed the VPATH test to
  test . = "$(srcdir)" 

which seems appropriate since recent Autoconf normalizes srcdir to '.'
if building in-place.

Cheers,
Ralf

    For AC_CONFIG_LINKS(X,X), do not clean X in a non-VPATH build.
    
    * automake.in (rewrite_inputs_into_dependencies): Do distribute
    inputs where input and output name are equal.  This relies on
    the assumption that it only happens with AC_CONFIG_LINKS.
    (handle_configure) <CONFIG_CLEAN_VPATH_FILES>: New variable, for
    links where source and dest are equal.
    * lib/am/clean.am (distclean-generic): Remove, if build tree not
    equal source tree.
    * tests/conflnk4.test: New test.
    * tests/Makefile.am: Adjust.
    * NEWS: Update.
    
    Signed-off-by: Ralf Wildenhues <address@hidden>

diff --git a/NEWS b/NEWS
index 4230abb..181ba05 100644
--- a/NEWS
+++ b/NEWS
@@ -63,6 +63,10 @@ New in 1.10a:
   - New macro AM_COND_IF for conditional evaluation and conditional
     config files.
 
+  - For AC_CONFIG_LINKS, if source and destination are equal, do not
+    remove the file in a non-VPATH build.  Such setups work with Autoconf
+    2.62 or newer.
+
 Bugs fixed in 1.10a:
 
 * Long standing bugs:
diff --git a/automake.in b/automake.in
index 68647e9..dc431fe 100755
--- a/automake.in
+++ b/automake.in
@@ -3936,7 +3936,7 @@ sub prepend_srcdir (@)
 # Compute a list of dependencies appropriate for the rebuild
 # rule of
 #   AC_CONFIG_FILES($OUTPUT:$INPUT[0]:$INPUTS[1]:...)
-# Also distribute $INPUTs which are not build by another AC_CONFIG_FILES.
+# Also distribute $INPUTs which are not built by another AC_CONFIG_FOOS.
 sub rewrite_inputs_into_dependencies ($@)
 {
   my ($file, @inputs) = @_;
@@ -3947,7 +3947,7 @@ sub rewrite_inputs_into_dependencies ($@)
       # We cannot create dependencies on shell variables.
       next if (substitute_ac_subst_variables $i) =~ /\$/;
 
-      if (exists $ac_config_files_location{$i})
+      if (exists $ac_config_files_location{$i} && $i ne $file)
        {
          my $di = dirname $i;
          if ($di eq $relative_dir)
@@ -4152,6 +4152,8 @@ sub handle_configure ($$$@)
   # Now look for other files in this directory which must be remade
   # by config.status, and generate rules for them.
   my @actual_other_files = ();
+  # These get cleaned only in a VPATH build.
+  my @actual_other_vpath_files = ();
   foreach my $lfile (@other_input_files)
     {
       my $file;
@@ -4242,7 +4244,14 @@ sub handle_configure ($$$@)
                  $local = undef;
                }
            }
-         push @actual_other_files, $local if $local;
+         if ($file ne $link)
+           {
+             push @actual_other_files, $local if $local;
+           }
+         else
+           {
+             push @actual_other_vpath_files, $local if $local;
+           }
        }
 
       # Do not process sources that contain shell variables.
@@ -4267,6 +4276,8 @@ sub handle_configure ($$$@)
   # These files get removed by "make distclean".
   define_pretty_variable ('CONFIG_CLEAN_FILES', TRUE, INTERNAL,
                          @actual_other_files);
+  define_pretty_variable ('CONFIG_CLEAN_VPATH_FILES', TRUE, INTERNAL,
+                         @actual_other_vpath_files);
 }
 
 # Handle C headers.
diff --git a/lib/am/clean.am b/lib/am/clean.am
index f3dd2c6..d74daca 100644
--- a/lib/am/clean.am
+++ b/lib/am/clean.am
@@ -1,5 +1,5 @@
 ## automake - create Makefile.in from Makefile.am
-## Copyright (C) 1994, 1995, 1996, 1998, 1999, 2001, 2003, 2004
+## Copyright (C) 1994, 1995, 1996, 1998, 1999, 2001, 2003, 2004, 2008
 ## Free Software Foundation, Inc.
 
 ## This program is free software; you can redistribute it and/or modify
@@ -29,6 +29,7 @@ clean-generic:
 distclean-am: distclean-generic clean-am
 distclean-generic:
        -test -z "$(CONFIG_CLEAN_FILES)" || rm -f $(CONFIG_CLEAN_FILES)
+       -test . = "$(srcdir)" || test -z "$(CONFIG_CLEAN_VPATH_FILES)" || rm -f 
$(CONFIG_CLEAN_VPATH_FILES)
 %DISTCLEAN_RMS%
 
 ## Makefiles and their dependencies cannot be cleaned by
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 8cddc57..45624af 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -181,6 +181,7 @@ confincl.test \
 conflnk.test \
 conflnk2.test \
 conflnk3.test \
+conflnk4.test \
 confsub.test \
 confvar.test \
 confvar2.test \
diff --git a/tests/conflnk4.test b/tests/conflnk4.test
new file mode 100755
index 0000000..6fc3fb7
--- /dev/null
+++ b/tests/conflnk4.test
@@ -0,0 +1,96 @@
+#! /bin/sh
+# Copyright (C) 2003, 2008 Free Software Foundation, Inc.
+#
+# This file is part of GNU Automake.
+#
+# GNU Automake is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3, or (at your option)
+# any later version.
+#
+# GNU Automake is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with Automake; see the file COPYING.  If not, write to
+# the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+# Boston, MA 02110-1301, USA.
+
+# Test to make sure links to _identical files_ created by AC_CONFIG_LINKS get
+# removed with `make distclean' only if doing a VPATH build.
+
+. ./defs || exit 1
+
+set -e
+
+mkdir nonmk-subdir sdir sdir/mk-subdir
+: > src
+: > sdir/Makefile.am
+: > sdir/src2
+: > nonmk-subdir/src3
+: > sdir/mk-subdir/src4
+
+cat >> Makefile.am <<'EOF'
+SUBDIRS = sdir
+test: distdir
+       test -f $(distdir)/src
+       test -f $(distdir)/sdir/src2
+EOF
+
+cat >>configure.in << 'EOF'
+AC_CONFIG_FILES(sdir/Makefile)
+AC_CONFIG_LINKS(src:src)
+AC_CONFIG_LINKS(sdir/src2:sdir/src2)
+AC_CONFIG_LINKS(nonmk-subdir/src3:nonmk-subdir/src3)
+AC_CONFIG_LINKS(sdir/mk-subdir/src4:sdir/mk-subdir/src4)
+AC_OUTPUT
+EOF
+
+$ACLOCAL
+$AUTOMAKE
+$AUTOCONF
+
+mkdir build
+cd build
+../configure
+
+# TODO: Make sure links are distributed
+$MAKE test
+
+# Make sure nothing is deleted by `make clean'
+$MAKE clean
+
+test -f ../src
+test -f ../sdir/src2
+test -f ../nonmk-subdir/src3
+test -f ../sdir/mk-subdir/src4
+
+# Make sure the links are deleted by `make distclean' and the original files
+# are not.
+$MAKE distclean
+
+test -f ../src
+test -f ../sdir/src2
+test -f ../nonmk-subdir/src3
+test -f ../sdir/mk-subdir/src4
+
+test -r src && exit 1
+test -r sdir/src2 && exit 1
+test -r nonmk-subdir/src3 && exit 1
+test -r sdir/mk-subdir/src4 && exit 1
+
+cd ..
+./configure
+
+# TODO: Make sure links are distributed
+$MAKE test
+
+# Make sure nothing is deleted by `make distclean'
+$MAKE distclean
+
+test -f src
+test -f sdir/src2
+test -f nonmk-subdir/src3
+test -f sdir/mk-subdir/src4