Change record ctors to only allow record-field-assignment expressions.

Previously, any expression that evaluates to a record may have been used
in a record ctor's expression list.  This didn't work in all cases,
doesn't provide any unique functionality that can't be done otherwise,
and is possibly a path to introducing subtle scripting errors.

BIT-1192 #closed

CHANGES

@@ -1,4 +1,9 @@
 
+2.2-478 | 2014-05-19 15:31:33 -0500
+
+  * Change record ctors to only allow record-field-assignment
+    expressions. (Jon Siwek)
+
 2.2-477 | 2014-05-19 14:13:00 -0500
 
   * Fix X509::Result record's "result" field to be set internally as type int instead of type count. (Bernhard Amann)

VERSION

@@ -1 +1 @@
-2.2-477
+2.2-478

src/Expr.cc

@@ -3398,8 +3398,8 @@ RecordConstructorExpr::RecordConstructorExpr(ListExpr* constructor_list)
 	if ( IsError() )
 		return;
 
-	// Spin through the list, which should be comprised of
-	// either record's or record-field-assign, and build up a
+	// Spin through the list, which should be comprised only of
+	// record-field-assign expressions, and build up a
 	// record type to associate with this constructor.
 	type_decl_list* record_types = new type_decl_list;
 
@@ -3409,32 +3409,17 @@ RecordConstructorExpr::RecordConstructorExpr(ListExpr* constructor_list)
 		Expr* e = exprs[i];
 		BroType* t = e->Type();
 
-		if ( e->Tag() == EXPR_FIELD_ASSIGN )
-			{
-			FieldAssignExpr* field = (FieldAssignExpr*) e;
-
-			BroType* field_type = field->Type()->Ref();
-			char* field_name = copy_string(field->FieldName());
-
-			record_types->append(new TypeDecl(field_type, field_name));
-			continue;
-			}
-
-		if ( t->Tag() != TYPE_RECORD )
+		if ( e->Tag() != EXPR_FIELD_ASSIGN )
 			{
 			Error("bad type in record constructor", e);
 			SetError();
 			continue;
 			}
 
-		// It's a record - add in its fields.
-		const RecordType* rt = t->AsRecordType();
-		int n = rt->NumFields();
-		for ( int j = 0; j < n; ++j )
-			{
-			const TypeDecl* td = rt->FieldDecl(j);
-			record_types->append(new TypeDecl(td->type->Ref(), td->id));
-			}
+		FieldAssignExpr* field = (FieldAssignExpr*) e;
+		BroType* field_type = field->Type()->Ref();
+		char* field_name = copy_string(field->FieldName());
+		record_types->append(new TypeDecl(field_type, field_name));
 		}
 
 	SetType(new RecordType(record_types));

testing/btest/Baseline/language.record-bad-ctor2/out

@@ -0,0 +1 @@
+error in /Users/jsiwek/Projects/bro/bro/testing/btest/.tmp/language.record-bad-ctor2/record-bad-ctor2.bro, line 14: bad type in record constructor ([[$cmd=echo hi]] and [$cmd=echo hi])

testing/btest/language/record-bad-ctor2.bro

@@ -0,0 +1,16 @@
+# @TEST-EXEC-FAIL: bro -b %INPUT >out 2>&1
+# @TEST-EXEC: TEST_DIFF_CANONIFIER=$SCRIPTS/diff-remove-abspath btest-diff out
+
+# Record ctor's expression list shouldn't accept "expressions that
+# eval in to record".  The expression list should only be comprised of
+# record-field-assignment expressions.
+
+type myrec: record {
+	cmd: string;
+	stdin: string &default="";
+	read_files: string &optional;
+};
+
+local bad = myrec([$cmd="echo hi"]);
+
+print bad;