[Minor] Fix one more corner case

diff --git a/src/libserver/html/html.cxx b/src/libserver/html/html.cxx
index d60210ba6e15857b95c5de742d3fc01618467df3..6cf3b959d3d263bec60bda32c57c4df470e2abda 100644 (file)
--- a/src/libserver/html/html.cxx
+++ b/src/libserver/html/html.cxx
@@ -1191,9 +1191,10 @@ html_append_tag_content(rspamd_mempool_t *pool,
                                        /* Add a space */
                                        hc->parsed += ' ';
                                }
+
                                hc->parsed.append(maybe_alt.value());
 
-                               if (!g_ascii_isspace (hc->parsed.back())) {
+                               if (!hc->parsed.empty() && !g_ascii_isspace (hc->parsed.back())) {
                                        /* Add a space */
                                        hc->parsed += ' ';
                                }