From 08e825fede28f22ce3fbaf494c3e06360ed74d7a Mon Sep 17 00:00:00 2001
From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Sat, 28 Dec 2019 18:26:09 +0000
Subject: [PATCH 1/1] Warning reporting: Provide &:local+global directive

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
---
 README                       | 7 +++++++
 generate                     | 9 ++++++++-
 tests/filter/Dir.mk.expected | 3 +++
 tests/filter/Dir.sd.mk       | 4 ++++
 4 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/README b/README
index 98fe313..41110ce 100644
--- a/README
+++ b/README
@@ -277,6 +277,11 @@ So pathname syntax is a subset of:
 	by the final warning state after processing all the toplevel
 	input files (including Final.sd.mk).
 
+&:local+global [&]VARIABLE ...
+	Suppresses the warning about seeing both VARIABLE and
+	&VARIABLE.  Any & specified in the RHS is redundant: this
+	always affects both versions identically.
+
 &:changequote NEWQUOTE
 	changes the escape sequence from & to literally NEWQUOTE
 	NEWQUOTE may be any series of of non-whitespace characters,
@@ -392,6 +397,8 @@ suppressed with the &:warn directive.  The warning tags are:
 	The same VARNAME was used both with and without an & prefix.
 	This can be confusing.  Also, if you avoid this then you will
 	get a warning iff you accidentally leave off a needed &.
+	(You can suppress this warning for a particular VARNAME with
+	the &:local+global directive.)
 
     single-char-var
 	A variable expansion like $FBAR.  make's expansion rules
diff --git a/generate b/generate
index 3caf4e6..61bbd50 100755
--- a/generate
+++ b/generate
@@ -289,9 +289,15 @@ sub process_input_mk ($$$$) {
 		}
 	    }
 	    next;
+	} elsif (s#^\s*$esc\:local\+global\s+(\S.*)$##) {
+	    foreach my $vn (split /\s+/, $1) {
+		$vn =~ s{^$esc}{};
+		$varref{$vn}{NoWarn} = 1;
+	    }
+	    next;
 	} elsif (s#^\s*$esc\:(?=(-?)include|macro)##) {
 	    $buffering_output='';
-	} elsif (m#^\s*$esc\:([a-z][-0-9a-z_]*)#) {
+	} elsif (m#^\s*$esc\:([a-z][-+0-9a-z_]*)#) {
 	    err "unknown directive &:$1 or bad argumnt syntax";
 	} elsif (s{^\s*${esc}TARGETS(?:_([0-9a-zA-Z_]+))?(?=\W)}{}) {
 	    my $t = $1 // 'all';
@@ -513,6 +519,7 @@ sub print_varref_warnings () {
     foreach my $vn (sort keys %varref) {
 	my $vv = $varref{$vn};
 	next unless $vv->{''} && $vv->{1};
+	next if $vv->{NoWarn};
 	wrncore 'local+global', "saw both $vn and &$vn" or return;
 	foreach my $amp ('', 1) {
 	    printf STDERR " saw %s%s at %s\n",
diff --git a/tests/filter/Dir.mk.expected b/tests/filter/Dir.mk.expected
index 14cc88a..7eecb23 100644
--- a/tests/filter/Dir.mk.expected
+++ b/tests/filter/Dir.mk.expected
@@ -12,6 +12,9 @@ TOP_WARN += 3
 # $(TOP_WARN)
 # $(TOP_WARN)
 
+# $(TOP_NOWARN1) $(NOWARN1)
+# $(TOP_NOWARN2) $(NOWARN2)
+
 ${eval ${call  some-macro, 42, $$x, {  $(foreach something) } }}
 
 # doctests:
diff --git a/tests/filter/Dir.sd.mk b/tests/filter/Dir.sd.mk
index 3a20de3..1a4eb1f 100644
--- a/tests/filter/Dir.sd.mk
+++ b/tests/filter/Dir.sd.mk
@@ -10,6 +10,10 @@ WARN += 3
 # $(&WARN)
 # &$WARN
 
+&:local+global NOWARN1 &NOWARN2
+# &$NOWARN1 $(NOWARN1)
+# &$NOWARN2 $(NOWARN2)
+
 &${ some-macro, 42, $x, { &$- $(foreach something) } }
 
 # doctests:
-- 
2.30.2