gh-44376: Write missing namespace declarations in xml.dom.minidom

[serhiy-storchaka]

Element.writexml() now writes the xmlns declarations needed to serialize the namespaces of the element and its attributes, if they are not already declared for an ancestor. A prefix is invented for a namespaced attribute without a prefix, because attributes cannot use the default namespace. The document is not modified by the serialization.

>>> doc = parseString("<doc/>")
>>> elem = doc.createElementNS("http://xml.python.org/ns", "p:elem")
>>> doc.documentElement.appendChild(elem)
>>> doc.documentElement.toxml()
'<doc><p:elem xmlns:p="http://xml.python.org/ns"/></doc>'

The namespaces in scope are passed down the recursion as a keyword-only argument. They are passed only to the standard implementation of writexml(); an overridden method is called with the documented signature, and computes them by walking the ancestors of the element.

• Issue: normalize namespace from minidom #44376

[read-the-docs-community]

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📚 cpython-previews | 🛠️ Build #34300776 | 📁 Comparing 6a76a10 against main (852381e)

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2 files changed

± library/xml.dom.minidom.html
± whatsnew/changelog.html