From 0eb0dd3797b2685a7a9e7776f5f17777dd59140f Mon Sep 17 00:00:00 2001
From: Eric Blake <eblake@redhat.com>
Date: Fri, 12 Nov 2010 14:10:32 -0700
Subject: [PATCH] maintainer-makefile: prohibit test x == x

* top/maint.mk (sc_prohibit_test_double_equal): New rule.
Based on a report by Matthias Bolte.

Signed-off-by: Eric Blake <eblake@redhat.com>
---
 ChangeLog    | 4 ++++
 top/maint.mk | 6 ++++++
 2 files changed, 10 insertions(+)

diff --git a/ChangeLog b/ChangeLog
index 8a9d7b665..21677e2bf 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,9 @@
 2010-11-12  Eric Blake  <eblake@redhat.com>
 
+	maintainer-makefile: prohibit test x == x
+	* top/maint.mk (sc_prohibit_test_double_equal): New rule.
+	Based on a report by Matthias Bolte.
+
 	bootstrap: allow FreeBSD gzip
 	* build-aux/bootstrap (get_version): Parse FreeBSD gzip version,
 	which has no '.' and goes to stderr.
diff --git a/top/maint.mk b/top/maint.mk
index 181a96fa4..d51944b0c 100644
--- a/top/maint.mk
+++ b/top/maint.mk
@@ -817,6 +817,12 @@ sc_prohibit_test_minus_ao:
 	halt='$(_ptm1); $(_ptm2)'					\
 	  $(_sc_search_regexp)
 
+# Avoid a test bashism.
+sc_prohibit_test_double_equal:
+	@prohibit='(\<test| \[+) .+ == '				\
+	halt='use "test x = x", not "test x =''= x"'			\
+	  $(_sc_search_regexp)
+
 # Each program that uses proper_name_utf8 must link with one of the
 # ICONV libraries.  Otherwise, some ICONV library must appear in LDADD.
 # The perl -0777 invocation below extracts the possibly-multi-line
-- 
2.11.0