From cf7f7e9dfdb0241d091655bca63edcdae5b81c03 Mon Sep 17 00:00:00 2001
From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Wed, 25 Dec 2019 17:08:19 +0000
Subject: [PATCH] Syntax: only some directives' RHS should be &-expanded

In principle this is an incompatible change but only for strange input
files and only if they use &:changequote.

We need an ad-hoc test for this.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
---
 README                                  |  3 ++-
 generate                                | 13 ++++++++-----
 tests/filter/sub/dir/Subdir.mk.expected |  3 +++
 tests/filter/sub/dir/Subdir.sd.mk       |  4 ++++
 4 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/README b/README
index 6bc8e82..63e4188 100644
--- a/README
+++ b/README
@@ -268,9 +268,10 @@ So pathname syntax is a subset of:
 	recognised at start of line only (possibly after lwsp)
 	args are processed for &
 
-&:include filename		filename should usually be foo.sd.mk
+&:include filename		filename should usually be [&]foo.sd.mk
 &:-include filename		tolerate nonexistent file
 	filenames are relative to $(top_srcdir)
+	RHS is &-expanded
 
 &!<lwsp>	disables & until EOL (and then disappears)
 
diff --git a/generate b/generate
index e7da435..e1efc06 100755
--- a/generate
+++ b/generate
@@ -147,8 +147,14 @@ sub process_input_mk ($$$$$$$$$) {
     $pfxmap{$_} = $srcdirmap{$_}.'/' foreach keys %srcdirmap;
 
     while (<$input>) {
-	if (s#^\s*$esc\:##) {
+	if (s#^\s*$esc\:changequote\s+(\S+)\s+$##) {
+	    $$esclitr = $1;
+	    $set_esc->();
+	    next;
+	} elsif (s#^\s*$esc\:(?=(-?)include)##) {
 	    $buffering_output='';
+	} elsif (m#^\s*$esc\:([a-z][-0-9a-z_]*)#) {
+	    die "unknown directive $1";
 	}
 	for (;;) {
 	    unless (s{^(.*?)$esc}{}) { o $_; last; }
@@ -194,11 +200,8 @@ sub process_input_mk ($$$$$$$$$) {
 				 $var_prefix, $var_prefix_name, $targets,
 				 $subf, $esclitr, $1);
 		o "\n";
-	    } elsif (m#^changequote\s+(\S+)\s+$#) {
-		$$esclitr = $1;
-		$set_esc->();
 	    } else {
-		die "unknown directive $_ ";
+		die "internal error buffering directive $_ ";
 	    }
 	}
     }
diff --git a/tests/filter/sub/dir/Subdir.mk.expected b/tests/filter/sub/dir/Subdir.mk.expected
index 9f7cb70..8a3e94f 100644
--- a/tests/filter/sub/dir/Subdir.mk.expected
+++ b/tests/filter/sub/dir/Subdir.mk.expected
@@ -1,5 +1,8 @@
 # autogenerated - do not edit
 # subdirectory test cases
+
+sub/dir/
+
 # doctests:
 
 sub/dir/all:: $(sub_dir_TARGETS)
diff --git a/tests/filter/sub/dir/Subdir.sd.mk b/tests/filter/sub/dir/Subdir.sd.mk
index f06ea99..99f6f4e 100644
--- a/tests/filter/sub/dir/Subdir.sd.mk
+++ b/tests/filter/sub/dir/Subdir.sd.mk
@@ -1,3 +1,7 @@
 # subdirectory test cases
+
+&:changequote &
+&/
+
 # doctests:
 &:include &doctest.sd.mk
-- 
2.30.2