Filtering leads to Null Pointer exception when saving

[Chris Wellington]

The result seems to be the same as that in bug 689286, but I think the cause may be distinct.

I am frequently getting "NullPointerException" errors when saving files. I've gotten the error on three different computers, Windows XP and Ubuntu Linux. Version info from one of the systems is below:
Product Version: Gephi 0.8.1 beta 201202141941
Java: 1.7.0_03; Java HotSpot(TM) Server VM 22.1-b02
System: Windows XP version 5.1 running on x86; Cp1252; en_US (gephi)
User directory: C:\Documents and Settings\wellingtonc\Application Data\.gephi\0.8.1\dev
Cache directory: C:\Documents and Settings\wellingtonc\Application Data\.gephi\0.8.1\dev\var\cache

The error occurs after I have used filtering to identify a subset of a graph and then moved that subset to a new workspace. For example, see the following steps:
Create a new project,
Add three nodes; connect two of them.
Filter -> Topology -> Giant Component
Apply Filter (the node not connected to the others is hidden)
Select "Export filtered graph to a new workspace", in the filter menu.
Go to the new workspace, save the file, everything works.
Close the project. Re-open it, and it will no longer save (it gives the error above).

I can upload the files if others are unable to reproduce this.

[Chris Wellington (chris-wellington)]

These are two files, one showing the file before applying the filter and creating the new workspace from filtered values, the other showing the result after doing that. I can successfully save the first (pre-filter) file, but get the NullPointer exception when trying to save the second (post-filter) file. Files are in tarball to avoid creating two comments.

[Sébastien Heymann (sebastien.heymann)]

Thanks, I copied your bug report on github, which is the bug tracker we use now:
https://github.com/gephi/gephi/issues/617