introduce &weaken attribute, which basically only prevents

the describe function for types to descend into record fields that
are marked with it.

With this, we can actually load the pacf scripts without crashing Bro
when running tests :)

scripts/base/frameworks/pacf/plugin.bro

@@ -85,7 +85,7 @@ export {
 	redef record PluginState += {
 		## The plugin that the state belongs to. (Defined separately
 		## because of cyclic type dependency.)
-		plugin: Plugin &optional;
+		plugin: Plugin &optional &weaken;
 	};
 
 }

scripts/base/init-default.bro

@@ -37,7 +37,8 @@
 @load base/frameworks/reporter
 @load base/frameworks/sumstats
 @load base/frameworks/tunnels
-#@load base/frameworks/pacf
+@load base/frameworks/openflow
+@load base/frameworks/pacf
 
 @load base/protocols/conn
 @load base/protocols/dhcp

src/Attr.cc

@@ -18,7 +18,7 @@ const char* attr_name(attr_tag t)
 		"&encrypt",
 		"&raw_output", "&mergeable", "&priority",
 		"&group", "&log", "&error_handler", "&type_column",
-		"(&tracked)", "&deprecated",
+		"(&tracked)", "&deprecated", "&weaken",
 	};
 
 	return attr_names[int(t)];
@@ -436,6 +436,11 @@ void Attributes::CheckAttr(Attr* a)
 			Error("&log applied to a type that cannot be logged");
 		break;
 
+	case ATTR_WEAKEN:
+		if ( ! in_record )
+			Error("&weaken applied outside of record");
+		break;
+
 	case ATTR_TYPE_COLUMN:
 		{
 		if ( type->Tag() != TYPE_PORT )

src/Attr.h

@@ -35,7 +35,8 @@ typedef enum {
 	ATTR_TYPE_COLUMN,	// for input framework
 	ATTR_TRACKED,	// hidden attribute, tracked by NotifierRegistry
 	ATTR_DEPRECATED,
-#define NUM_ATTRS (int(ATTR_DEPRECATED) + 1)
+	ATTR_WEAKEN,
+#define NUM_ATTRS (int(ATTR_WEAKEN) + 1)
 } attr_tag;
 
 class Attr : public BroObj {

src/Type.cc

@@ -1129,6 +1129,9 @@ void RecordType::DescribeFields(ODesc* d) const
 			const TypeDecl* td = FieldDecl(i);
 			d->Add(td->id);
 			d->Add(":");
+			if ( td->FindAttr(ATTR_WEAKEN) )
+				d->Add("<weakened>");
+			else
 				td->type->Describe(d);
 			d->Add(";");
 			}
@@ -1170,6 +1173,9 @@ void RecordType::DescribeFieldsReST(ODesc* d, bool func_args) const
 			}
 
 		const TypeDecl* td = FieldDecl(i);
+		if ( td->FindAttr(ATTR_WEAKEN) )
+			d->Add("<weakened>");
+		else
 			td->DescribeReST(d);
 
 		if ( func_args )

src/parse.y

@@ -2,7 +2,7 @@
 // See the file "COPYING" in the main distribution directory for copyright.
 %}
 
-%expect 78
+%expect 81
 
 %token TOK_ADD TOK_ADD_TO TOK_ADDR TOK_ANY
 %token TOK_ATENDIF TOK_ATELSE TOK_ATIF TOK_ATIFDEF TOK_ATIFNDEF
@@ -25,7 +25,7 @@
 %token TOK_ATTR_PERSISTENT TOK_ATTR_SYNCHRONIZED
 %token TOK_ATTR_RAW_OUTPUT TOK_ATTR_MERGEABLE
 %token TOK_ATTR_PRIORITY TOK_ATTR_LOG TOK_ATTR_ERROR_HANDLER
-%token TOK_ATTR_TYPE_COLUMN TOK_ATTR_DEPRECATED
+%token TOK_ATTR_TYPE_COLUMN TOK_ATTR_DEPRECATED TOK_ATTR_WEAKEN
 
 %token TOK_DEBUG
 
@@ -1291,6 +1291,8 @@ attr:
 			{ $$ = new Attr(ATTR_ERROR_HANDLER); }
 	|	TOK_ATTR_DEPRECATED
 			{ $$ = new Attr(ATTR_DEPRECATED); }
+	|	TOK_ATTR_WEAKEN
+			{ $$ = new Attr(ATTR_WEAKEN); }
 	;
 
 stmt:

src/scan.l

@@ -276,6 +276,7 @@ when	return TOK_WHEN;
 &type_column	return TOK_ATTR_TYPE_COLUMN;
 &read_expire	return TOK_ATTR_EXPIRE_READ;
 &redef		return TOK_ATTR_REDEF;
+&weaken	return TOK_ATTR_WEAKEN;
 &write_expire	return TOK_ATTR_EXPIRE_WRITE;
 
 &encrypt {