steve@charon:~/gerbv/test$ valgrind --trace-children=yes --suppressions=gerbv.supp --error-exitcode=127 --errors-for-leak-kinds=definite --leak-check=full -s --exit-on-first-error=yes --expensive-definedness-checks=yes --keep-stacktraces=alloc-and-free --  gerbv --export=png --window=640x480 --export=rs274x --output=outputs2/example_numpres_numpres.pcb.output_unplated-drill.grb-again outputs2/example_numpres_numpres.pcb.output_unplated-drill.grb
==27813== Memcheck, a memory error detector
==27813== Copyright (C) 2002-2022, and GNU GPL'd, by Julian Seward et al.
==27813== Using Valgrind-3.20.0 and LibVEX; rerun with -h for copyright info
==27813== Command: gerbv --export=png --window=640x480 --export=rs274x --output=outputs2/example_numpres_numpres.pcb.output_unplated-drill.grb-again outputs2/example_numpres_numpres.pcb.output_unplated-drill.grb
==27813== 
==27813== Invalid read of size 8
==27813==    at 0x4E5C227: gerbv_destroy_image (gerb_image.c:192)
==27813==    by 0x429943: main (main.c:1196)
==27813==  Address 0xbe73af0 is 48 bytes inside a block of size 56 free'd
==27813==    at 0x4C31740: free (vg_replace_malloc.c:884)
==27813==    by 0x4E5C23A: gerbv_destroy_image (gerb_image.c:193)
==27813==    by 0x4E5AB68: _export (export-rs274x.c:556)
==27813==    by 0x4E5ABFA: gerbv_export_rs274x_file_from_image (export-rs274x.c:577)
==27813==    by 0x4298D9: main (main.c:1181)
==27813==  Block was alloc'd at
==27813==    at 0x4C33914: calloc (vg_replace_malloc.c:1340)
==27813==    by 0x63D68E0: g_malloc0 (in /lib/x86_64-linux-gnu/libglib-2.0.so.0.4800.2)
==27813==    by 0x4E5C7AE: gerbv_image_return_new_netstate (gerb_image.c:338)
==27813==    by 0x4E6497E: parse_rs274x (gerber.c:1452)
==27813==    by 0x4E61115: gerber_parse_file_segment (gerber.c:268)
==27813==    by 0x4E62C05: parse_gerb (gerber.c:795)
==27813==    by 0x4E6AA8A: gerbv_open_image (gerbv.c:822)
==27813==    by 0x4E691FC: gerbv_open_layer_from_filename_with_color (gerbv.c:254)
==27813==    by 0x428AE9: main (main.c:966)
==27813== 
==27813== 
==27813== Exit program on first error (--exit-on-first-error=yes)

gerbv_layer_t *
gerbv_image_duplicate_layer (gerbv_layer_t *oldLayer) {
    gerbv_layer_t *newLayer = g_new (gerbv_layer_t,1);
    
    *newLayer = *oldLayer;
    newLayer->name = g_strdup (oldLayer->name);
	newLayer->next = NULL;  // SJH fix potential double free
    return newLayer;
}

static gerbv_netstate_t *
gerbv_image_duplicate_state (gerbv_netstate_t *oldState)
{
	gerbv_netstate_t *newState = g_new (gerbv_netstate_t, 1);

	*newState = *oldState;
	newState->next = NULL;  // SJH fix potential double free
	return newState;
}