[PATCH] NPE on combination of ZWSP, NBSP and <fo:inline>

The following line in my XSL:FO reliably causes a NPE when generating a PDF:

<fo:inline>&#x200B;<fo:inline>&#xA0;</fo:inline>x</fo:inline> 

Removing any single element of this line makes the NPE go away:

• The outer <fo:inline>
• The Zero-Width Space
• The inner <fo:inline>
• The Non-Breaking Space
• The "x" text

(My actual document has more content within the outer <fo:inline>; I just removed everything else to provide the minimum content needed to reproduce the NPE.)

The NPE is reported as:

SEVERE: Exception
org.apache.fop.apps.FOPException
java.lang.NullPointerException
        at org.apache.fop.cli.InputHandler.transformTo(InputHandler.java:296)
        at org.apache.fop.cli.InputHandler.renderTo(InputHandler.java:116)
        at org.apache.fop.cli.Main.startFOP(Main.java:183)
        at org.apache.fop.cli.Main.main(Main.java:214)
Caused by: java.lang.NullPointerException
... 

The complete FOP output is attached as fop.log.

The complete input XSL:F0 is attached as bad.fo. The line of interest is near the bottom of the file. I have placed a comment above it listing several variations of the line with each element removed one at a time. Any of those alternatives prevents the NPE from occurring.

My command line is:

fop/fop-2.6/fop/fop -c WD/fop-config.xml -fo bad.fo bad.pdf 2>&1 | tee fop.log

My FOP config file is attached as fop-config.xml.