diff --git a/dtool/src/dtoolutil/filename.I b/dtool/src/dtoolutil/filename.I
index e1d19462dc..de3a98cad3 100644
--- a/dtool/src/dtoolutil/filename.I
+++ b/dtool/src/dtoolutil/filename.I
@@ -381,6 +381,19 @@ is_binary() const {
   return ((_flags & F_binary) != 0);
 }
 
+////////////////////////////////////////////////////////////////////
+//     Function: Filename::is_binary_or_text
+//       Access: Published
+//  Description: Returns true either is_binary() or is_text() is true;
+//               that is, that the filename has been specified as
+//               either binary or text.  If this is false, the
+//               filename has not been specified.
+////////////////////////////////////////////////////////////////////
+INLINE bool Filename::
+is_binary_or_text() const {
+  return ((_flags & (F_binary | F_text)) != 0);
+}
+
 ////////////////////////////////////////////////////////////////////
 //     Function: Filename::is_text
 //       Access: Published
diff --git a/dtool/src/dtoolutil/filename.cxx b/dtool/src/dtoolutil/filename.cxx
index 315489e35c..0c8b011476 100644
--- a/dtool/src/dtoolutil/filename.cxx
+++ b/dtool/src/dtoolutil/filename.cxx
@@ -1069,7 +1069,9 @@ make_canonical() {
   // Use realpath in order to resolve symlinks properly
   char newpath [PATH_MAX + 1];
   if (realpath(c_str(), newpath) != NULL) {
-    (*this) = newpath;
+    Filename newpath_fn(newpath);
+    newpath_fn._flags = _flags;
+    (*this) = newpath_fn;
   }
 #endif
 
@@ -1151,6 +1153,7 @@ make_true_case() {
     return true;
   }
 
+  true_case._flags = _flags;
   (*this) = true_case;
   return true;
 
@@ -1935,7 +1938,7 @@ scan_directory() const {
 bool Filename::
 open_read(ifstream &stream) const {
   assert(!get_pattern());
-  assert(is_text() || is_binary());
+  assert(is_binary_or_text());
 
   ios_openmode open_mode = ios::in;
 
@@ -1971,7 +1974,7 @@ open_read(ifstream &stream) const {
 bool Filename::
 open_write(ofstream &stream, bool truncate) const {
   assert(!get_pattern());
-  assert(is_text() || is_binary());
+  assert(is_binary_or_text());
 
   ios_openmode open_mode = ios::out;
 
@@ -2022,7 +2025,7 @@ open_write(ofstream &stream, bool truncate) const {
 bool Filename::
 open_append(ofstream &stream) const {
   assert(!get_pattern());
-  assert(is_text() || is_binary());
+  assert(is_binary_or_text());
 
   ios_openmode open_mode = ios::app;
 
@@ -2059,7 +2062,7 @@ open_append(ofstream &stream) const {
 bool Filename::
 open_read_write(fstream &stream, bool truncate) const {
   assert(!get_pattern());
-  assert(is_text() || is_binary());
+  assert(is_binary_or_text());
 
   ios_openmode open_mode = ios::out | ios::in;
 
@@ -2107,7 +2110,7 @@ open_read_write(fstream &stream, bool truncate) const {
 bool Filename::
 open_read_append(fstream &stream) const {
   assert(!get_pattern());
-  assert(is_text() || is_binary());
+  assert(is_binary_or_text());
 
   ios_openmode open_mode = ios::app | ios::in;
 
@@ -2145,7 +2148,7 @@ open_read_append(fstream &stream) const {
 bool Filename::
 open_read(pifstream &stream) const {
   assert(!get_pattern());
-  assert(is_text() || is_binary());
+  assert(is_binary_or_text());
 
   ios_openmode open_mode = ios::in;
 
@@ -2183,7 +2186,7 @@ open_read(pifstream &stream) const {
 bool Filename::
 open_write(pofstream &stream, bool truncate) const {
   assert(!get_pattern());
-  assert(is_text() || is_binary());
+  assert(is_binary_or_text());
 
   ios_openmode open_mode = ios::out;
 
@@ -2236,7 +2239,7 @@ open_write(pofstream &stream, bool truncate) const {
 bool Filename::
 open_append(pofstream &stream) const {
   assert(!get_pattern());
-  assert(is_text() || is_binary());
+  assert(is_binary_or_text());
 
   ios_openmode open_mode = ios::app;
 
@@ -2275,7 +2278,7 @@ open_append(pofstream &stream) const {
 bool Filename::
 open_read_write(pfstream &stream, bool truncate) const {
   assert(!get_pattern());
-  assert(is_text() || is_binary());
+  assert(is_binary_or_text());
 
   ios_openmode open_mode = ios::out | ios::in;
 
@@ -2325,7 +2328,7 @@ open_read_write(pfstream &stream, bool truncate) const {
 bool Filename::
 open_read_append(pfstream &stream) const {
   assert(!get_pattern());
-  assert(is_text() || is_binary());
+  assert(is_binary_or_text());
 
   ios_openmode open_mode = ios::app | ios::in;
 
@@ -2530,7 +2533,9 @@ rename_to(const Filename &other) const {
 //       Access: Published
 //  Description: Copies the file to the indicated new filename, by
 //               reading the contents and writing it to the new file.
-//               Returns true if successful, false on failure.
+//               Returns true if successful, false on failure.  The
+//               copy is always binary, regardless of the filename
+//               settings.
 ////////////////////////////////////////////////////////////////////
 bool Filename::
 copy_to(const Filename &other) const {
diff --git a/dtool/src/dtoolutil/filename.h b/dtool/src/dtoolutil/filename.h
index c5cf86f353..e73cfa2e63 100644
--- a/dtool/src/dtoolutil/filename.h
+++ b/dtool/src/dtoolutil/filename.h
@@ -133,6 +133,7 @@ PUBLISHED:
   INLINE void set_text();
   INLINE bool is_binary() const;
   INLINE bool is_text() const;
+  INLINE bool is_binary_or_text() const;
 
   INLINE void set_type(Type type);
   INLINE Type get_type() const;