istream-chain: Fixed crash caused by earlier io_add_stream() support change.

diff --git a/src/lib/istream-chain.c b/src/lib/istream-chain.c
index 194fda2e5d6fcaf7dc9981791cce23587b110c82..2c7e35ba89956407613c896143cd82287437da4d 100644 (file)
--- a/src/lib/istream-chain.c
+++ b/src/lib/istream-chain.c
@@ -56,7 +56,8 @@ i_stream_chain_append_internal(struct istream_chain *chain,
        DLLIST2_APPEND(&chain->head, &chain->tail, link);
        /* if io_add_istream() has been added to this chain stream, notify
           the callback that we have more data available. */
-       i_stream_set_input_pending(stream, TRUE);
+       if (stream != NULL)
+               i_stream_set_input_pending(stream, TRUE);
 }
 
 void i_stream_chain_append(struct istream_chain *chain, struct istream *stream)