dist: fix bugs #81558 and #81557.

From https://bugs.gnu.org/81558 and https://bugs.gnu.org/81557
(Bruno Haible).

The filter for overly long file names had as many dots as the
maximum, so it rejected names of exactly that length; it needs one
more.

99 characters is the v7 limit, not a portable limit for tarballs in
general; ustar, the default since 1.18, stores longer names.  The
manual said otherwise.

* bin/automake.in (handle_dist): one dot more than the maximum.
* lib/am/distdir.am (distdir-am): name the option in the diagnostic.
* doc/automake.texi (List of Automake options): rewrite the
filename-length-max entry; the limit depends on the archive format,
and the length counted includes the $(distdir)/ prefix.
* t/filename-length-max.sh: new test.
* t/list-of-tests.mk (handwritten_TESTS): add it.
* NEWS: mention both.

diff --git a/NEWS b/NEWS
index 372ea46f3153d25adaedf686d9ad2e1c91c661f4..3a401a3739af67d5dcedcb8250f21ecb878376eb 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -21,6 +21,15 @@ New in 1.18.2 (????-??-??):
   - `make dist' now fails when tar fails, instead of exiting
     successfully with a truncated archive.
 
   - `make dist' now fails when tar fails, instead of exiting
     successfully with a truncated archive.
 

+  - The filename-length-max=N option no longer rejects file names of
+    exactly N characters; as documented, only longer ones are.
+    (bug#81558)
+
+  - The manual no longer presents 99 characters as the portable limit
+    for file names in any archive format: it is the limit of the v7
+    format, whereas ustar, the default since Automake 1.18, stores
+    longer names. (bug#81557)
+

 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 New in 1.18.1 (2025-06-25):
 
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 New in 1.18.1 (2025-06-25):
 

diff --git a/bin/automake.in b/bin/automake.in
index f7e84ebcc8238f3584f82fdeda5d6cd36401e197..1035dae62dafe8987db177671ae6931fffd96c6c 100644 (file)
--- a/bin/automake.in
+++ b/bin/automake.in
@@ -3970,7 +3970,7 @@ sub handle_dist ()
   $transform{'DIST-TARGETS'} = join (' ', @dist_targets);
 
   my $flm = option ('filename-length-max');
   $transform{'DIST-TARGETS'} = join (' ', @dist_targets);
 
   my $flm = option ('filename-length-max');

-  my $filename_filter = $flm ? '.' x $flm->[1] : '';
+  my $filename_filter = $flm ? '.' x (1 + $flm->[1]) : '';

 
   $output_rules .= file_contents ('distdir',
                                  new Automake::Location,
 
   $output_rules .= file_contents ('distdir',
                                  new Automake::Location,

diff --git a/doc/automake.texi b/doc/automake.texi
index 86800245390d6deda6a2af3e3dd3421a10d9c1e2..c81b0897fea46b9cd7d39564b2265dacc44381a4 100644 (file)
--- a/doc/automake.texi
+++ b/doc/automake.texi
@@ -11310,13 +11310,29 @@ is deprecated, as the @samp{compress} program is obsolete.
 Support for it will be removed altogether in Automake 2.0.
 @trindex dist-tarZ
 
 Support for it will be removed altogether in Automake 2.0.
 @trindex dist-tarZ
 

-@item @option{filename-length-max=99}
-@cindex Option, @option{filename-length-max=99}
-@opindex filename-length-max=99
-Abort if file names longer than 99 characters are found during
-@samp{make dist}.  Such long file names are generally considered not to
-be portable in tarballs.  See the @option{tar-v7} and @option{tar-ustar}
-options below.  This option should be used in the top-level
+@item @option{filename-length-max=@var{max}}
+@cindex Option, @option{filename-length-max=@var{max}}
+@opindex filename-length-max=@var{max}
+Abort @samp{make dist} if the distribution contains file names longer
+than @var{max} characters; names of exactly @var{max} characters are
+accepted.  What is measured is the name under which @command{tar} will
+store the file, so it includes the @file{@var{package}-@var{version}/}
+prefix.
+
+How long a file name may be depends on the archive format in use
+(@pxref{tar-formats}).  The @option{tar-v7} format supports at most 99
+characters, hence the customary @option{filename-length-max=99}.  The
+@option{tar-ustar} format, the default since Automake 1.18, stores file
+names of up to 256 characters, provided they can be split at a directory
+separator into a prefix of at most 155 characters and a remainder of at
+most 100; any name of at most 100 characters therefore fits, and
+@option{filename-length-max=155} is a safe choice as long as no single
+component of a file name exceeds 100 characters.  The @option{tar-pax}
+format does not limit file name lengths at all.  So, unless you also
+distribute a V7 archive, @option{filename-length-max=99} is stricter
+than necessary.
+
+This option should be used in the top-level

 @file{Makefile.am} or as an argument of @code{AM_INIT_AUTOMAKE} in
 @file{configure.ac}; it will be ignored otherwise.  It will also be
 ignored in sub-packages of nested packages (@pxref{Subpackages}).
 @file{Makefile.am} or as an argument of @code{AM_INIT_AUTOMAKE} in
 @file{configure.ac}; it will be ignored otherwise.  It will also be
 ignored in sub-packages of nested packages (@pxref{Subpackages}).

diff --git a/lib/am/distdir.am b/lib/am/distdir.am
index ceb78c8d9c851779d94544af0eab15c2cdef9400..b817779adb07003ce8a56311b6e9d06dc36df601 100644 (file)
--- a/lib/am/distdir.am
+++ b/lib/am/distdir.am
@@ -291,9 +291,12 @@ if %?TOPDIR_P%
          ! -type d ! -perm -444 -exec $(install_sh) -c -m a+r {} {} \; \
        || chmod -R a+r "$(distdir)"
 if %?FILENAME_FILTER%
          ! -type d ! -perm -444 -exec $(install_sh) -c -m a+r {} {} \; \
        || chmod -R a+r "$(distdir)"
 if %?FILENAME_FILTER%

+## %FILENAME_FILTER% is one dot longer than the requested maximum, so
+## that it matches only the file names that exceed it.

        @if test -z "$(am__skip_length_check)" && find "$(distdir)" -type f -print | \
          grep '^%FILENAME_FILTER%' 1>&2; then \
        @if test -z "$(am__skip_length_check)" && find "$(distdir)" -type f -print | \
          grep '^%FILENAME_FILTER%' 1>&2; then \

-         echo 'error: the above filenames are too long' 1>&2; \
+         echo 'error: the above filenames are too long' \
+              '(see the filename-length-max option)' 1>&2; \

          exit 1; \
        else :; fi
 endif %?FILENAME_FILTER%
          exit 1; \
        else :; fi
 endif %?FILENAME_FILTER%

diff --git a/t/filename-length-max.sh b/t/filename-length-max.sh
new file mode 100644 (file)
index 0000000..4c94ec7
--- /dev/null
+++ b/t/filename-length-max.sh
@@ -0,0 +1,58 @@
+#! /bin/sh
+# Copyright (C) 2026 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 2, 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 <https://www.gnu.org/licenses/>.
+
+# The filename-length-max=N option must accept file names of exactly N
+# characters, and reject only the longer ones.  See automake bug#81558.
+
+. test-init.sh
+
+echo AC_OUTPUT >> configure.ac
+
+# Long enough to be the longest file name of the distribution.
+long=aaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
+
+mkdir dir
+: > dir/$long
+
+# The maximum we ask for is the length of the name under which tar would
+# store that file, that is, including the "$distdir/" prefix.  Word
+# splitting gets rid of the padding some 'wc' implementations write.
+set -- $(printf '%s' "$distdir/dir/$long" | wc -c)
+max=$1
+echo "maximum file name length: $max" # For debugging.
+
+cat > Makefile.am << END
+AUTOMAKE_OPTIONS = filename-length-max=$max
+EXTRA_DIST = dir
+END
+
+$ACLOCAL
+$AUTOCONF
+$AUTOMAKE
+./configure
+
+# A file name of exactly $max characters is not too long.
+$MAKE dist
+test -f $distdir.tar.gz
+
+# One character more, and it is.
+: > dir/a$long
+run_make -E -e FAIL dist
+grep 'filenames are too long' stderr
+# And only that file gets reported.
+test 1 -eq $(grep -c "$long" stderr)
+
+:

diff --git a/t/list-of-tests.mk b/t/list-of-tests.mk
index cd9b6bc555a0b0035dda313724143b478c0483b5..e56d257bcb65901f8e8d736fe89ce4abc304ad45 100644 (file)
--- a/t/list-of-tests.mk
+++ b/t/list-of-tests.mk
@@ -494,6 +494,7 @@ t/extra-sources-no-spurious.sh \
 t/extra-sources.sh \
 t/extra.sh \
 t/f90only.sh \
 t/extra-sources.sh \
 t/extra.sh \
 t/f90only.sh \

+t/filename-length-max.sh \

 t/flavor.sh \
 t/flibs.sh \
 t/fn99.sh \
 t/flavor.sh \
 t/flibs.sh \
 t/fn99.sh \