[automake-commit] branch master updated: automake: avoid Perl-level warning on empty variable $().

[Karl Berry]

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karl pushed a commit to branch master
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View the commit online:
https://git.savannah.gnu.org/gitweb/?p=automake.git;a=commitdiff;h=b020a9ca888a3af2e18ecd77fa66c6ca6811329f

The following commit(s) were added to refs/heads/master by this push:
     new b020a9ca8 automake: avoid Perl-level warning on empty variable $().
b020a9ca8 is described below

commit b020a9ca888a3af2e18ecd77fa66c6ca6811329f
Author: Karl Berry <karl@freefriends.org>
AuthorDate: Sun Jun 30 13:26:51 2024 -0700

    automake: avoid Perl-level warning on empty variable $().
    
    https://lists.gnu.org/archive/html/automake/2024-06/msg00085.html
    
    * lib/Automake/Variable.pm (scan_variable_expansions): recognize
    and do nothing if the variable name is empty: $().
    * t/varempty.sh: new test.
    * t/list-of-tests.mk (handwritten_TESTS): add it.
---
 lib/Automake/Variable.pm |  6 +++++-
 t/list-of-tests.mk       |  1 +
 t/varempty.sh            | 36 ++++++++++++++++++++++++++++++++++++
 3 files changed, 42 insertions(+), 1 deletion(-)

diff --git a/lib/Automake/Variable.pm b/lib/Automake/Variable.pm
index db1f6378d..f97aab59f 100644
--- a/lib/Automake/Variable.pm
+++ b/lib/Automake/Variable.pm
@@ -751,7 +751,11 @@ sub scan_variable_expansions ($)
   while ($text =~ m{\$(?:\{([^\}]*)\}|\(([^\)]*)\)|(\$))}g)
     {
       my $var = $1 || $2 || $3;
-      next if $var eq '$';
+      next if (! defined $var) || ($var eq '$');
+      # we check for $var being defined because NetworkManager and other
+      # packages use the strange construct $().
+      # https://lists.gnu.org/archive/html/automake/2024-06/msg00085.html
+      
       # The occurrence may look like $(string1[:subst1=[subst2]]) but
       # we want only 'string1'.
       $var =~ s/:[^:=]*=[^=]*$//;
diff --git a/t/list-of-tests.mk b/t/list-of-tests.mk
index 1e0f364ba..e80ace470 100644
--- a/t/list-of-tests.mk
+++ b/t/list-of-tests.mk
@@ -1282,6 +1282,7 @@ t/vala-per-target-flags.sh \
 t/vala-recursive-setup.sh \
 t/vala-vapi.sh \
 t/vala-vpath.sh \
+t/varempty.sh \
 t/vars.sh \
 t/vars3.sh \
 t/var-recurs.sh \
diff --git a/t/varempty.sh b/t/varempty.sh
new file mode 100644
index 000000000..9eb45c421
--- /dev/null
+++ b/t/varempty.sh
@@ -0,0 +1,36 @@
+#! /bin/sh
+# Copyright (C) 2024 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/>.
+
+# An empty variable name $() should not cause a Perl warning, namely:
+#   Use of uninitialized value $var in string eq at
+#   .../lib/Automake/Variable.pm line 754, <GEN2> line 3.
+# (in scan_variable_expansions)
+# 
+# This showed up with the NetworkManager and other packages in Fedora:
+# https://lists.gnu.org/archive/html/automake/2024-06/msg00085.html
+# (The actual purpose of the "$()" is unclear.)
+
+. test-init.sh
+
+cat > Makefile.am << 'END'
+x:
+       $()
+END
+
+$ACLOCAL
+$AUTOMAKE
+
+: