diff --git a/TODO b/TODO
index 82fbfc18..ccbc0538 100644
--- a/TODO
+++ b/TODO
@@ -1,3 +1,10 @@
+- 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
diff --git a/libvips/conversion/im_copy.c b/libvips/conversion/im_copy.c
index 6ea8f4b8..21c2c634 100644
--- a/libvips/conversion/im_copy.c
+++ b/libvips/conversion/im_copy.c
@@ -114,7 +114,7 @@ static int
 im_copy_set_all( IMAGE *in, IMAGE *out, 
 	VipsType type, float xres, float yres, int xoffset, int yoffset,
 	int bands, VipsBandFmt bandfmt, VipsCoding coding )
-{	
+{
 	/* Check args.
 	 */
         if( im_check_coding_known( "im_copy", in ) ||
@@ -162,25 +162,6 @@ im_copy_set_all( IMAGE *in, IMAGE *out,
 	return( 0 );
 }
 
-/**
- * im_copy:
- * @in: input image
- * @out: output image
- *
- * Copy an image. VIPS copies images by copying pointers, so this operation is
- * fast, even for very large images.
- *
- * See also: im_copy(), im_copy_set(), im_copy_morph().
- *
- * Returns: 0 on success, -1 on error.
- */
-int 
-im_copy( IMAGE *in, IMAGE *out )
-{
-	return( im_copy_set( in, out, 
-		in->Type, in->Xres, in->Yres, 0, 0 ) );
-}
-
 /**
  * im_copy_set:
  * @in: input image
@@ -234,6 +215,25 @@ im_copy_morph( IMAGE *in, IMAGE *out,
 		bands, bandfmt, coding ) );
 }
 
+/**
+ * im_copy:
+ * @in: input image
+ * @out: output image
+ *
+ * Copy an image. VIPS copies images by copying pointers, so this operation is
+ * fast, even for very large images.
+ *
+ * See also: im_copy(), im_copy_set(), im_copy_morph().
+ *
+ * Returns: 0 on success, -1 on error.
+ */
+int 
+im_copy( IMAGE *in, IMAGE *out )
+{
+	return( im_copy_set( in, out, 
+		in->Type, in->Xres, in->Yres, 0, 0 ) );
+}
+
 /**
  * im_copy_set_meta:
  * @in: input image
diff --git a/libvips/deprecated/package.c b/libvips/deprecated/package.c
index 697b9b00..b63bc620 100644
--- a/libvips/deprecated/package.c
+++ b/libvips/deprecated/package.c
@@ -974,14 +974,6 @@ build_args( im_function *fn, im_object *vargv, int argc, char **argv )
 	return( 0 );
 }
 
-/* Free a region, but return 0 so we can be used as a close callback.
- */
-static void
-region_local_image_cb( VipsImage *main, VipsRegion *reg )
-{
-	g_object_unref( reg );
-}
-
 /* Make a region on sub, closed by callback on main.
  */
 static int
@@ -991,8 +983,7 @@ region_local_image( IMAGE *main, IMAGE *sub )
 
 	if( !(reg = vips_region_new( sub )) )
 		return( -1 );
-	g_signal_connect( main, "close", 
-		G_CALLBACK( region_local_image_cb ), reg ); 
+	vips_object_local( main, reg ); 
  
         return( 0 );
 }
diff --git a/libvips/deprecated/vips7compat.c b/libvips/deprecated/vips7compat.c
index ff2f080f..33e52cb7 100644
--- a/libvips/deprecated/vips7compat.c
+++ b/libvips/deprecated/vips7compat.c
@@ -815,7 +815,13 @@ im_add( IMAGE *in1, IMAGE *in2, IMAGE *out )
 		g_object_unref( x );
 		return( -1 );
 	}
-	g_object_unref( x );
+
+	/* When im_copy() is vips8'd it'll make a ref to in which will be
+	 * junked when the copy shuts down and we can unref x directly.
+	 *
+	 * Until then, we have to use the "close" signal to delay the unref.
+	 */
+	vips_object_local( out, x ); 
 
 	return( 0 );
 }
diff --git a/libvips/format/fits.c b/libvips/format/fits.c
index 914f2dec..e5cd292d 100644
--- a/libvips/format/fits.c
+++ b/libvips/format/fits.c
@@ -146,6 +146,12 @@ vips_fits_close( VipsFits *fits )
 	VIPS_FREE( fits->buffer );
 }
 
+static void
+vips_fits_close_cb( VipsImage *image, VipsFits *fits )
+{
+	vips_fits_close( fits );
+}
+
 static VipsFits *
 vips_fits_new_read( const char *filename, VipsImage *out, int band_select )
 {
@@ -162,7 +168,7 @@ vips_fits_new_read( const char *filename, VipsImage *out, int band_select )
 	fits->band_select = band_select;
 	fits->buffer = NULL;
 	g_signal_connect( out, "close", 
-		G_CALLBACK( vips_fits_close ), fits );
+		G_CALLBACK( vips_fits_close_cb ), fits );
 
 	status = 0;
 	if( fits_open_file( &fits->fptr, filename, READONLY, &status ) ) {
@@ -444,7 +450,7 @@ fits2vips( const char *filename, VipsImage *out, int band_select )
 		return( -1 );
 	}
 
-	/* Don't vips_fits_close(), we need it to stcik around for the
+	/* Don't vips_fits_close(), we need it to stick around for the
 	 * generate.
 	 */
 
@@ -605,7 +611,7 @@ vips_fits_new_write( VipsImage *in, const char *filename )
 	fits->band_select = -1;
 	fits->buffer = NULL;
 	g_signal_connect( in, "close", 
-		G_CALLBACK( vips_fits_close ), fits );
+		G_CALLBACK( vips_fits_close_cb ), fits );
 
 	if( !(fits->filename = im_strdup( NULL, filename )) )
 		return( NULL );
diff --git a/libvips/iofuncs/generate.c b/libvips/iofuncs/generate.c
index 31b27fd4..7d00b3ac 100644
--- a/libvips/iofuncs/generate.c
+++ b/libvips/iofuncs/generate.c
@@ -79,7 +79,7 @@
  */
 
 /*
-#define DEBUG_IO
+#define VIPS_DEBUG
  */
 
 #ifdef HAVE_CONFIG_H
@@ -605,6 +605,7 @@ vips_image_generate( VipsImage *image,
 
 	VIPS_DEBUG_MSG( "vips_image_generate: %p\n", image ); 
 
+	g_assert( generate );
 	g_assert( vips_object_sanity( VIPS_OBJECT( image ) ) );
 
 	if( !image->hint_set ) {
diff --git a/libvips/iofuncs/image.c b/libvips/iofuncs/image.c
index a4bea8a9..feb67572 100644
--- a/libvips/iofuncs/image.c
+++ b/libvips/iofuncs/image.c
@@ -1226,6 +1226,8 @@ vips_image_class_init( VipsImageClass *class )
 static void
 vips_image_init( VipsImage *image )
 {
+	VIPS_DEBUG_MSG( "vips_image_init: %p\n", image );
+
 	/* Default to native order.
 	 */
 	image->magic = vips_amiMSBfirst() ? VIPS_MAGIC_SPARC : VIPS_MAGIC_INTEL;
@@ -1412,8 +1414,8 @@ void
 vips_image_set_progress( VipsImage *image, gboolean progress )
 {
 	if( progress && !image->progress_signal ) {
-		VIPS_DEBUG_MSG( "vips_image_set_progress: %s\n", 
-			image->filename );
+		VIPS_DEBUG_MSG( "vips_image_set_progress: %p %s\n", 
+			image, image->filename );
 		image->progress_signal = image;
 	}
 	else
diff --git a/libvips/iofuncs/object.c b/libvips/iofuncs/object.c
index 9823ff99..72d69274 100644
--- a/libvips/iofuncs/object.c
+++ b/libvips/iofuncs/object.c
@@ -179,6 +179,8 @@ vips_object_sanity( VipsObject *object )
 		printf( "sanity failure: " );
 		vips_object_print_name( object );
 		printf( " %s\n", vips_buf_all( &buf ) );
+
+		return( FALSE );
 	}
 
 	return( TRUE );
diff --git a/libvips/iofuncs/region.c b/libvips/iofuncs/region.c
index 0eb144b4..2584b971 100644
--- a/libvips/iofuncs/region.c
+++ b/libvips/iofuncs/region.c
@@ -205,8 +205,6 @@ vips__region_start( VipsRegion *region )
 {
 	VipsImage *image = region->im;
 
-        /* Have we a sequence running on this region? Start one if not.
-         */
         if( !region->seq && image->start ) {
                 g_mutex_lock( image->sslock );
                 region->seq = 
@@ -231,8 +229,6 @@ vips__region_stop( VipsRegion *region )
 {
 	IMAGE *image = region->im;
 
-        /* Stop any running sequence.
-         */
         if( region->seq && image->stop ) {
 		int result;
 
@@ -318,6 +314,28 @@ vips_region_print( VipsObject *object, VipsBuf *buf )
 	VIPS_OBJECT_CLASS( vips_region_parent_class )->print( object, buf );
 }
 
+static void
+vips_region_sanity( VipsObject *object, VipsBuf *buf )
+{
+	VipsRegion *region = VIPS_REGION( object );
+
+	vips_object_sanity( VIPS_OBJECT( region->im ) );
+
+	switch( region->im->dtype ) { 
+	case VIPS_IMAGE_PARTIAL:
+		/* Start and stop can be NULL, but not generate.
+		 */
+		if( !region->im->generate )
+			vips_buf_appends( buf, "generate NULL in partial\n" );
+		break;
+	
+	default:
+		break;
+	}
+
+	VIPS_OBJECT_CLASS( vips_region_parent_class )->sanity( object, buf );
+}
+
 /* If a region is being created in one thread (eg. the main thread) and then
  * used in another (eg. a worker thread), the new thread needs to tell VIPS
  * to stop sanity g_assert() fails. The previous owner needs to
@@ -407,6 +425,7 @@ vips_region_class_init( VipsRegionClass *class )
 	gobject_class->dispose = vips_region_dispose;
 
 	vobject_class->print = vips_region_print;
+	vobject_class->print = vips_region_sanity;
 	vobject_class->build = vips_region_build;
 }
 
@@ -442,6 +461,11 @@ vips_region_new( VipsImage *image )
 		return( NULL );
 	}
 
+#ifdef DEBUG
+#endif /*DEBUG*/
+	g_assert( vips_object_sanity( VIPS_OBJECT( image ) ) );
+	g_assert( vips_object_sanity( VIPS_OBJECT( region ) ) );
+
 	return( region ); 
 }
 
diff --git a/libvips/iofuncs/sink.c b/libvips/iofuncs/sink.c
index 1a0bf5fb..0106d8e8 100644
--- a/libvips/iofuncs/sink.c
+++ b/libvips/iofuncs/sink.c
@@ -218,6 +218,8 @@ sink_init( Sink *sink,
 	VipsStartFn start, VipsGenerateFn generate, VipsStopFn stop,
 	void *a, void *b )
 {
+	g_assert( generate );
+
 	vips_sink_base_init( &sink->sink_base, image );
 
 	sink->t = NULL;