Hi Frederic,
NetworkManager:
Use of uninitialized value $var in string eq at
/usr/share/automake-1.16/Automake/Variable.pm line 754, <GEN2> line 1169.
>From the Makefile.am you sent me separately (attached here for the
record), it seems that is coming from the use of $() in:
introspection/%.h: introspection/%.c
$()
Accordingly, I changed scan_variable_expansions (in Variable.pm) to not
worry if the variable name is empty (patch and test below). Could you
retry NetworkManager or the other packages and make sure the Perl
warning is gone, please?
It wasn't entirely clear to me if the line
_vapi_name = $(subst /,_,$(subst -,_,$(subst .,_,$(1))))
might also be causing trouble, but I think Automake already recognizes
that ok (and gives a warning, by default, but an Automake warning, not a
Perl warning.)
As an aside, I'm curious as to why the $() is used. It seems
a mysterious way to do nothing. Do you know? --thanks, karl.
-----------------------------------------------------------------------------
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: $().
* t/varempty.sh: new test.
* t/list-of-tests.mk (handwritten_TESTS): add it.
diff --git a/lib/Automake/Variable.pm b/lib/Automake/Variable.pm
index db1f6378d..f97aab59f 100644
--- a/lib/Automake/Variable.pm
+++ b/lib/Automake/Variable.pm
@@ -751,7 +751,11 @@ sub scan_variable_expansions ($)
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
+
+:
Running command: git commit \-q \-F \.\/vc\-dwim\-log\-wBh6_U \-\-author\=Karl\
Berry\ \<karl\@freefriends\.org\> \-\- ChangeLog
+ set +x
compile finished at Sun Jun 30 13:26:51 2024
Makefile.am.gz
Description: Binary data
Makefile.vapigen.gz
Description: Binary data
