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POETSII / Orchestrator

The Orchestrator is the configuration and run-time management system for POETS platforms.
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XML parser rejects re-declaration of xmlns #221

Closed m8pple closed 3 years ago

m8pple commented 3 years ago

The XML parser treats xmlns as a normal attribute, so if any element other than Graphs declares a namespace (even to re-declare the same namespace), then it is rejected. Re-declaration is fairly common when pasting together fragments of XML, and should be invisible outside the parser. For example, this occurs in one of the example v4 files sent to Andrew to help him ~reinvent the wheel~ write an XML parser from scratch:

https://github.com/POETSII/poets_improvement_proposals/blob/2a355282f3aa3912bdacf4ec50bf25199bdf310d/proposed/PIP-0020/xml/ic/apps/betweeness_centrality_16_16_20_20_v4.xml#L1-L3

I think the XML parser is currently unaware of namespaces (e.g. #200), so this is not something easily fixed properly.

Suggested workaround is to add an optional xmlns attribute to V4Grammar3.ocfg on the GraphType and GraphInstance elements, as these are the most likely elements to re-declare their namespace.

m8pple commented 3 years ago

Workaround in this commit: 74e27478dee3e7031cda1c608e8abb1080a83756

heliosfa commented 3 years ago

Another suggested fix: change grammar to allow re-declaration/multiple definition of XMLNS

m8pple commented 3 years ago

I'm not sure what you mean by changing the grammar. Re-declaring xmlns is a fundamental property of XML. The patch I proposed changes it in two places in the ocfg grammar.

So I've rebased the proposed patch from last month into #264 , as it is still a blocking issue.

heliosfa commented 3 years ago

resolved in #264