"graphml" value for the "for" attribute of a key shouldn't throw an exception

[Guillaume Ansanay-Alex <guillaume.ansanay@…>]

The GraphML specification (​http://graphml.graphdrawing.org/xmlns/1.1/graphml-structure.xsd) states that the possible values for the "for" attribute of a key are "all", "graphml", "graph", "node", "edge", "hyperedge", "port" and "endpoint".

(Actually the "graphml" value is absent from the documentation of the scheme, but present as a possible value in the .xsd file. I have sent an e-mail to the authors of the specification, mentioning this ambiguity.)

If the value is "graphml", the graphml reader in BGL throws an exception : "Attribute for is not valid: graphml".

This value should be added to the ones accepted by the BGL reader, otherwise files such as those produced by the yEd graph editor cannot be read.

[Jeremiah Willcock]

What are the semantics for graphml when it is used as the value of for? I don't see it mentioned anywhere in the spec or in the yFiles documentation other than as just a possible option. How does yEd use for="graphml"?

[Will Plano]

I've just come across this defect, also while trying to parse a yEd file.

According to the documentation at graphml.graphdrawing.org/specification/schema_element.xsd.htm the for="graphml" key attribute is for data associated with "the whole collection of graphs described by the content of <graphml>" Since read_graphml only deals with a single graph in the file, I beleive it is correct to silently ignore this section.

As for how yEd uses it, it looks like it's for shared resources within the file...

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
...
snip schema definitions for spam filter
...
  <!--Created by yFiles for Java 2.10-->
  <key for="graphml" id="d0" yfiles.type="resources"/>
...
snip
...
  <data key="d0">
    <y:Resources/>
  </data>
</graphml>

see the attached patch on the duplicate ticket 7155

[Jeremiah Willcock]

(In [83961]) Applied patch from #7155 to add "graphml" as a value for "for"; fixes #7155; fixes #7016