Support for XML Namespaces

[ammachado]

What problem are you trying to solve?

Change namespaced tags without being required to know the namespace prefix. For example, on the following XML, I want to replace the schemaLocation attribute on the beans tag.

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:aop="http://www.springframework.org/schema/aop"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.0.xsd
                           http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.0.xsd">
</bean>

There are situations where the namespace URI remains the same, but the prefix changes. I can try change the attribute xsi:schemaLocation, but for that the prefix should match.

Describe the solution you'd like

• Add regex support to ChangeTagAttribute (I already have this working, I will contribute a PR #3920);
• Add support to name, namespace-uri and local-name on XPathMatcher; #3925 and #4287
• Add a namespaces field on Xml.Document and Xml.Tag, mapping the declared prefixes and namespaces; #3925 and
• Add a namespace or a namespacePrefix field on Xml.Tag and Xml.Attribute, identifying the namespace of that particular tag/attribute. #3925
• Move tags/attributes between namespaces

Have you considered any alternatives or workarounds?

No.

Additional context

Are you interested in contributing this feature to OpenRewrite?

[timtebeek]

Seems reasonable, thanks! Might tie into some of the schemaLocation changes we do in rewrite-migrate-java.

[ammachado]

Probably a few of the existing Java EE9/10 recipes could be improved with this, also create new ones, specially new recipes to refactor schemaLocation for Spring XML files.

[knutwannheden]

With that PR merged, I think this ticket can now be closed. What fo you guys think, @ammachado and @timtebeek ?

[timtebeek]

We had added a disabled tests previously; think we can reevaluate the @Disabled on that tests before we close https://github.com/openrewrite/rewrite/blob/22ac272d0a37fe1023af153ec68aef3ab7926849/rewrite-xml/src/test/java/org/openrewrite/xml/XPathMatcherTest.java#L223-L226

[ammachado]

3925 does not consider namespaces on org.openrewrite.xml.SemanticallyEqual.

[evie-lau]

Also need to finish support for name and namespace-uri functions in XPathMatcher. The latter function may potentially require a refactor or rewrite.