Contextual Substitution with LuaLateX

Question

Contextual substition doesn't seem to work with LuaLateX, while it works fine with XeLateX. Am I doing something wrong or is this a bug?

\documentclass{article}
\usepackage{fontspec}
\setmainfont{Linux Libertine O}

\begin{document}
\textvbaraccent{i} fä f?
\end{document}

XeLaTeX

LuaLaTeX

(notice the spacing between the upper part of the 'f' and the first dot of the 'ä' and the space between the 'f' and the '?')

Answer 1

The problem seems to have been solved with the new release of TeX Live 2013 (presently in test version). Here's the output obtained with

> lualatex --version
This is LuaTeX, Version beta-0.76.0-2013052718  (TeX Live 2013) (rev 4627)

Execute  'luatex --credits'  for credits and version details.

There is NO warranty. Redistribution of this software is covered by
the terms of the GNU General Public License, version 2 or (at your option)
any later version. For more information about these matters, see the file
named COPYING and the LuaTeX source.

Copyright 2013 Taco Hoekwater, the LuaTeX Team.

And here's the file list

 *File List*
 article.cls    2007/10/19 v1.4h Standard LaTeX document class
  size10.clo    2007/10/19 v1.4h Standard LaTeX file (size option)
fontspec.sty    2013/05/20 v2.3c Font selection for XeLaTeX and LuaLaTeX
   expl3.sty    2013/03/14 v4469 L3 Experimental code bundle wrapper
 l3names.sty    2012/12/07 v4346 L3 Namespace for primitives
l3bootstrap.sty    2013/01/08 v4420 L3 Experimental bootstrap code
  luatex.sty    2010/03/09 v0.4 LuaTeX basic definition package (HO)
infwarerr.sty    2010/04/08 v1.3 Providing info/warning/error messages (HO)
ifluatex.sty    2010/03/01 v1.3 Provides the ifluatex switch (HO)
    etex.sty    1998/03/26 v2.0 eTeX basic definition package (PEB)
luatex-loader.sty    2010/03/09 v0.4 Lua module loader (HO)
pdftexcmds.sty    2011/11/29 v0.20 Utility functions of pdfTeX for LuaTeX (HO)
 ltxcmds.sty    2011/11/09 v1.22 LaTeX kernel commands for general use (HO)
   ifpdf.sty    2011/01/30 v2.3 Provides the ifpdf switch (HO)
l3basics.sty    2013/01/10 v4428 L3 Basic definitions
 l3expan.sty    2013/02/03 v4458 L3 Argument expansion
    l3tl.sty    2013/01/08 v4415 L3 Token lists
   l3seq.sty    2013/01/12 v4434 L3 Sequences and stacks
   l3int.sty    2013/01/13 v4444 L3 Integers
 l3quark.sty    2012/11/04 v4268 L3 Quarks
   l3prg.sty    2013/02/13 v4459 L3 Control structures
 l3clist.sty    2013/01/08 v4414 L3 Comma separated lists
 l3token.sty    2013/01/10 v4428 L3 Experimental token manipulation
  l3prop.sty    2013/01/09 v4423 L3 Property lists
   l3msg.sty    2013/01/08 v4412 L3 Messages
  l3file.sty    2013/01/14 v4446 L3 File and I/O operations
  l3skip.sty    2013/01/13 v4444 L3 Dimensions and skips
  l3keys.sty    2013/02/24 v4461 L3 Experimental key-value interfaces
    l3fp.sty    2013/01/19 v4449 L3 Floating points
   l3box.sty    2013/01/08 v4411 L3 Experimental boxes
l3coffins.sty    2012/09/09 v4212 L3 Coffin code layer
 l3color.sty    2012/08/29 v4156 L3 Experimental color support
l3luatex.sty    2012/08/03 v4049 L3 Experimental LuaTeX-specific functions
l3candidates.sty    2013/03/14 v4468 L3 Experimental additions to l3kernel
  xparse.sty    2013/03/12 v4467 L3 Experimental document command parser
luaotfload.sty    2013/05/23 v2.2d OpenType layout system
luatexbase.sty    2013/05/11 v0.6 Resource management for the LuaTeX macro progr
ammer
luatexbase-compat.sty    2011/05/24 v0.4 Compatibility tools for LuaTeX
luatexbase-modutils.sty    2013/05/11 v0.6 Module utilities for LuaTeX
luatexbase-loader.sty    2013/05/11 v0.6 Lua module loader for LuaTeX
luatexbase-regs.sty    2011/05/24 v0.4 Registers allocation for LuaTeX
luatexbase-attr.sty    2013/05/11 v0.6 Attributes allocation for LuaTeX
luatexbase-cctb.sty    2013/05/11 v0.6 Catcodetable allocation for LuaTeX
luatexbase-mcb.sty    2013/05/11 v0.6 Callback management for LuaTeX
fontspec-patches.sty    2013/05/20 v2.3c Font selection for XeLaTeX and LuaLaTeX

fixltx2e.sty    2006/09/13 v1.1m fixes to LaTeX
fontspec-luatex.sty    2013/05/20 v2.3c Font selection for XeLaTeX and LuaLaTeX
 fontenc.sty
  eu2enc.def    2010/05/27 v0.1h Experimental Unicode font encodings
  eu2lmr.fd    2009/10/30 v1.6 Font defs for Latin Modern
xunicode.sty    2011/09/09 v0.981 provides access to latin accents and many othe
r characters in Unicode lower plane
 eu2lmss.fd    2009/10/30 v1.6 Font defs for Latin Modern
graphicx.sty    1999/02/16 v1.0f Enhanced LaTeX Graphics (DPC,SPQR)
  keyval.sty    1999/03/16 v1.13 key=value parser (DPC)
graphics.sty    2009/02/05 v1.0o Standard LaTeX Graphics (DPC,SPQR)
    trig.sty    1999/03/16 v1.09 sin cos tan (DPC)
graphics.cfg    2010/04/23 v1.9 graphics configuration of TeX Live
  pdftex.def    2011/05/27 v0.06d Graphics/color for pdfTeX
fontspec.cfg
   t3cmr.fd    2001/12/31 TIPA font definitions
supp-pdf.mkii
epstopdf-base.sty    2010/02/09 v2.5 Base part for package epstopdf
  grfext.sty    2010/08/19 v1.1 Manage graphics extensions (HO)
kvdefinekeys.sty    2011/04/07 v1.3 Define keys (HO)
kvoptions.sty    2011/06/30 v3.11 Key value format for package options (HO)
kvsetkeys.sty    2012/04/25 v1.16 Key value parser (HO)
etexcmds.sty    2011/02/16 v1.5 Avoid name clashes with e-TeX commands (HO)
epstopdf-sys.cfg    2010/07/13 v1.3 Configuration of (r)epstopdf for TeX Live
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