oop deleted one png init too many

fuzz/test_fuzz.sh

@@ -14,8 +14,13 @@ export VIPS_WARNING=0
 ret=0
 
 for fuzzer in *_fuzzer; do
+  fail=0
 	find "common_fuzzer_corpus" -type f -not -empty -print0 \
-	  | xargs -0 -n1 "./$fuzzer" || ret=1
+	  | xargs -0 -n1 "./$fuzzer" || fail=1
+  if [ $fail ]; then
+    echo FAIL $fuzzer
+    ret=1
+  fi
 done
 
 exit $ret

libvips/foreign/vipspng.c

@@ -208,6 +208,10 @@ read_open_input( Read *read )
 			return( -1 );
 		if( read->seek_position != -1 ) 
 			fseek( read->fp, read->seek_position, SEEK_SET );
+
+		/* Just takes a copy of the fp.
+		 */
+		png_init_io( read->pPng, read->fp );
 	}
 
 	return( 0 );
@@ -324,7 +328,6 @@ read_new_filename( VipsImage *out, const char *name, gboolean fail )
 		return( NULL );
 	}
 
-	png_init_io( read->pPng, read->fp );
 	read_info( read ); 
 
 	return( read );

test/test_descriptors

@@ -188,7 +188,7 @@ func_exec_program ()
 
   if test -f "$progdir/$program"; then
     # Add our own library path to LD_LIBRARY_PATH
-    LD_LIBRARY_PATH="/home/john/GIT/libvips/libvips/.libs:/home/john/vips/lib:$LD_LIBRARY_PATH"
+    LD_LIBRARY_PATH="/home/john/GIT/libvips/libvips/.libs:/usr/lib/x86_64-linux-gnu:$LD_LIBRARY_PATH"
 
     # Some systems cannot cope with colon-terminated LD_LIBRARY_PATH
     # The second colon is a workaround for a bug in BeOS R4 sed

test/test_descriptors.sh

@@ -26,3 +26,7 @@ fi
 if test_supported pngload; then
 	./test_descriptors $test_images/sample.png
 fi
+
+if test_supported webpload; then
+	./test_descriptors $test_images/1.webp
+fi