Disable "Show Output Anyway" button if empty file

Sometimes when compilation fails a PDF file is created but is empty
and the viewer gives an error when trying to view it. One such
example is compiling the current lib/examples/PDF-comment.lyx file
with TeX fonts and the following version of LuaTeX:

  beta-0.80.0 (TeX Live 2015) (rev 5238)

diff --git a/src/Buffer.cpp b/src/Buffer.cpp
index ae06ff89f46e2164d78e0e721fdb652604b56c55..e6096af747d328d284e3c8d13eb62744cb13c989 100644 (file)
--- a/src/Buffer.cpp
+++ b/src/Buffer.cpp
@@ -2440,7 +2440,7 @@ bool Buffer::getStatus(FuncRequest const & cmd, FuncStatus & flag)
 
        case LFUN_BUFFER_VIEW_CACHE:
                (d->preview_file_).refresh();
-               enable = (d->preview_file_).exists();
+               enable = (d->preview_file_).exists() && !(d->preview_file_).isFileEmpty();
                break;
 
        default: