distdir: avoid duplicate `find' traversal with subpackages.

[Ralf Wildenhues]

When "make dist" is run in a package tree that has subpackages, those
tasks that are already done by the top package need not be repeated by
a subpackage.  For the length check (option filename-length-max=99) we
already do this, as well as for the initial removal of part of the
distdir tree, but for the mode fixing command, this was not done.
Consequently, with a deep package hierarchy, the code was traversing
the tree quite a bit more often than necessary.

This patch fixes it.  This is not a bugfix, but only an optimization
issue; the test that I added does not fail with the prior code, but it
would fail if the new code failed to traverse the whole tree.

Pushed to master.

Cheers,
Ralf

    distdir: avoid duplicate `find' traversal with subpackages.
    
    * lib/am/distdir.am (distdir) [%?SUBDIRS%]: When recursing, set
    `am__skip_mode_fix'.
    [%?TOPDIR_P%]: When `$(am__skip_mode_fix)' is set, avoid tree
    walk.
    * tests/subpkg4.test: New test, to ensure that we still walk the
    whole tree while fixing permissions.  We don't ensure it is
    walked once only.
    * tests/Makefile.am: Update.

diff --git a/lib/am/distdir.am b/lib/am/distdir.am
index 5ee7b5c..9fc03cb 100644
--- a/lib/am/distdir.am
+++ b/lib/am/distdir.am
@@ -249,7 +249,7 @@ if %?SUBDIRS%
            $(am__relativize); \
            new_top_distdir=$$reldir; \
            echo " (cd $$subdir && $(MAKE) $(AM_MAKEFLAGS) 
top_distdir="$$new_top_distdir" distdir="$$new_distdir" \\"; \
-           echo "     am__remove_distdir=: am__skip_length_check=: distdir)"; \
+           echo "     am__remove_distdir=: am__skip_length_check=: 
am__skip_mode_fix=: distdir)"; \
            ($(am__cd) $$subdir && \
              $(MAKE) $(AM_MAKEFLAGS) \
                top_distdir="$$new_top_distdir" \
@@ -260,6 +260,8 @@ if %?SUBDIRS%
                am__remove_distdir=: \
 ## Disable filename length check:
                am__skip_length_check=: \
+## No need to fix modes more than once:
+               am__skip_mode_fix=: \
                distdir) \
              || exit 1; \
          fi; \
@@ -293,8 +295,13 @@ endif %?DIST-TARGETS%
 ## We use $(install_sh) because that is a known-portable way to modify
 ## the file in place in the source tree.
 ##
+## If we are being invoked recursively, then there is no need to walk
+## the whole subtree again.  This is a complexity reduction for a deep
+## hierarchy of subpackages.
+##
 if %?TOPDIR_P%
-       -find "$(distdir)" -type d ! -perm -777 -exec chmod a+rwx {} \; -o \
+       -test -n "$(am__skip_mode_fix)" \
+       || find "$(distdir)" -type d ! -perm -777 -exec chmod a+rwx {} \; -o \
          ! -type d ! -perm -444 -links 1 -exec chmod a+r {} \; -o \
          ! -type d ! -perm -400 -exec chmod a+r {} \; -o \
          ! -type d ! -perm -444 -exec $(install_sh) -c -m a+r {} {} \; \
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 09b979c..afcfda8 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -629,6 +629,7 @@ subobjname.test \
 subpkg.test \
 subpkg2.test \
 subpkg3.test \
+subpkg4.test \
 subst.test \
 subst2.test \
 subst3.test \
diff --git a/tests/subpkg4.test b/tests/subpkg4.test
new file mode 100755
index 0000000..592b37e
--- /dev/null
+++ b/tests/subpkg4.test
@@ -0,0 +1,73 @@
+#! /bin/sh
+# Copyright (C) 2006, 2009  Free Software Foundation, Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3, or (at your option)
+# any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# Test to ensure `distdir' fixes the mode of files and directories
+# copied into `$(distdir)', even with sub-packages.
+
+. ./defs || Exit 1
+
+set -e
+
+cat >Makefile.am <<'END'
+SUBDIRS = subpkg
+test-distdir-is-readable:
+       bad_dirs=`find $(distdir) -type d ! -perm -777 -print`; \
+       if test -n "$$bad_dirs"; then \
+         echo "directories not permissive: $$bad_dirs" >&2; \
+         exit 1; \
+       fi
+       bad_files=`find $(distdir) ! -type d ! -perm -444 -print`; \
+       if test -n "$$bad_files"; then \
+         echo "file not permissive: $$bad_files" >&2; \
+         exit 1; \
+       fi
+END
+
+cat >>configure.in <<'END'
+AC_CONFIG_SUBDIRS([subpkg])
+AC_OUTPUT
+END
+
+mkdir subpkg subpkg/dir
+echo foobar >subpkg/foobar
+echo baz > subpkg/dir/baz
+
+chmod go-rwx subpkg/foobar subpkg/dir/baz subpkg/dir
+
+cat >subpkg/Makefile.am <<'END'
+EXTRA_DIST = foobar dir
+END
+
+cat >subpkg/configure.in <<'END'
+AC_INIT([subpkg], [1.0])
+AM_INIT_AUTOMAKE
+AC_CONFIG_FILES([Makefile])
+AC_OUTPUT
+END
+
+$ACLOCAL
+$AUTOMAKE
+$AUTOCONF
+
+cd subpkg
+$ACLOCAL
+$AUTOMAKE
+$AUTOCONF
+cd ..
+
+./configure
+$MAKE distdir
+$MAKE test-distdir-is-readable