fix vips8 CLI

the vips8 CLI needed updating for the new refcount strategy

TODO

@@ -1,12 +1,3 @@
-- try 
-
-	$ vips add babe.jpg babe2.jpg out.v
-
-  VIPS:ERROR:object.c:815:vips_object_real_build: assertion failed:
-  (!object->constructed)
-
-
-
 - also VipsFormat ... could this replace vips_image_new_from_string()? or
   could we call this from vips_image_new_from_string()? 
 
@@ -27,8 +18,6 @@ wrap new API for C++
 
 
 
-- matlab write
-
 - Magick: 
 
 	- do we bundle "convert" in the OS X / win32 builds? if we don't we
@@ -50,7 +39,7 @@ wrap new API for C++
 - leak check, again
 
 
-- add MATLAB write
+- add matlab write
 
 - need a way to make the vips.1 etc. man pages
 

libvips/iofuncs/image.c

@@ -391,7 +391,18 @@ vips_image_dispose( GObject *gobject )
 static VipsObject *
 vips_image_new_from_file_object( const char *string )
 {
-	return( VIPS_OBJECT( vips_image_new_from_file( string ) ) );
+	VipsImage *image;
+
+	/* We mustn't _build() the object here, so we can't just call
+	 * vips_image_new_from_file().
+	 */
+	image = VIPS_IMAGE( g_object_new( VIPS_TYPE_IMAGE, NULL ) );
+	g_object_set( image,
+		"filename", string,
+		"mode", "r",
+		NULL );
+
+	return( VIPS_OBJECT( image ) );
 }
 
 static void

libvips/iofuncs/object.c

@@ -1082,11 +1082,11 @@ vips_object_set_argument_from_string( VipsObject *object,
 			return( -1 );
 
 		g_value_init( &gvalue, G_TYPE_OBJECT );
-
-		/* VipsObject is GInitiallyUnowned, so the gvalue now has a
-		 * ref count 1 image.
-		 */
 		g_value_set_object( &gvalue, object );
+
+		/* The GValue now has a ref, we can drop ours.
+		 */
+		g_object_unref( object );
 	}
 	else if( G_IS_PARAM_SPEC_BOOLEAN( pspec ) ) {
 		gboolean b;