From abb703a0c09917bd22650a99fb0b327d8f1ef63f Mon Sep 17 00:00:00 2001
From: Alexandre Duret-Lutz <adl@gnu.org>
Date: Sun, 8 Sep 2002 19:28:44 +0000
Subject: [PATCH] * automake.in (macro_define): Warn about `:=' assignments. *
 tests/colneq.test: Check for this warning.

---
 ChangeLog         |  3 +++
 automake.in       |  7 +++++++
 tests/colneq.test | 13 ++++++++++---
 3 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 5e80295c..83987eb0 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,8 @@
 2002-09-08  Alexandre Duret-Lutz  <duret_g@epita.fr>
 
+	* automake.in (macro_define): Warn about `:=' assignments.
+	* tests/colneq.test: Check for this warning.
+
 	* automake.texi (Include): Fragments are always distributed.
 	* NEWS: Likewise.
 
diff --git a/automake.in b/automake.in
index 4b8f147e..2cbfbad9 100755
--- a/automake.in
+++ b/automake.in
@@ -6176,6 +6176,13 @@ sub macro_define ($$$$$$)
        "$var: variable names starting with `_' are not portable")
     if $var =~ /^_/;
 
+  # `:='-style assignments are not acknowledged by POSIX.  Moreover it
+  # has multiple meanings.  In GNU make or BSD make it means "assign
+  # with immediate expansion", while in OSF make it is used for
+  # conditional assignments.
+  msg ('portability', $where, "`:='-style assignments are not portable")
+    if $type eq ':';
+
   check_variable_expansions ($value, $where);
 
   $cond ||= 'TRUE';
diff --git a/tests/colneq.test b/tests/colneq.test
index db1d151f..cf4aea9c 100755
--- a/tests/colneq.test
+++ b/tests/colneq.test
@@ -18,15 +18,22 @@
 # the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 # Boston, MA 02111-1307, USA.
 
-# Test that := definitions work.
+# Test that := definitions produce warnings, but otherwise work.
 
 . ./defs || exit 1
 
+set -e
+
 cat > Makefile.am << 'END'
-AUTOMAKE_OPTIONS = -Wno-portability
 ICONS := $(wildcard *.xbm)
 data_DATA = $(ICONS)
 END
 
-$ACLOCAL || exit 1
+$ACLOCAL
+$AUTOMAKE 2> stderr && exit 1
+cat stderr
+grep ':=.*not portable' stderr
+
+echo 'AUTOMAKE_OPTIONS = -Wno-portability' >> Makefile.am
 $AUTOMAKE
+grep 'ICONS :=' Makefile.in
-- 
2.43.5