fix(docx): create document.xml.rels when missing in comment.py - #1790

Reviewed at head ff947c15 (base 34040c9). Two-state check with a minimal unpacked DOCX that has no word/_rels/document.xml.rels, plus a variant whose rels part already exists (rId1 styles):

• ✅ Base reproduces defect 2: the four comment parts are written, no relationships part is created.
• ✅ Head creates word/_rels/document.xml.rels on first touch with exactly the four comment relationships rId1-rId4 (Id/Type/Target match _COMMENT_RELS); a rerun is byte-stable; the .docx round trip contains the part.
• ✅ Existing-rels path is untouched: appends the four relationships after the highest existing rId, original preserved, and the result validates against the repo's OPC schema.
• ✅ python -m py_compile clean; construction uses stdlib minidom while all parsing stays on defusedxml.

One change needed — the created part is missing the OPC namespace declaration. It serializes as:

<Relationships><Relationship Id="rId1" ... /></Relationships>

xml.dom.minidom keeps the namespace passed to createDocument() in the DOM but does not emit it when serializing — only explicitly-set attributes are written (same behaviour on CPython 3.9, 3.11 and 3.12). Against the repo's own office/schemas/ecma/fouth-edition/opc-relationships.xsd the part fails validation ("No matching global declaration available for the validation root", xmllint rc 3), and namespace-aware consumers ({http://schemas.openxmlformats.org/package/2006/relationships}Relationship) see zero relationships — i.e. defect 2 persists for anything that resolves namespaces.

Suggested:

1. Set the declaration explicitly after root = dom.documentElement — one line:

   root.setAttribute("xmlns", "http://schemas.openxmlformats.org/package/2006/relationships")

   I applied exactly this line to a scratch copy: the part then validates (xmllint rc 0) and ElementTree resolves {...}Relationships with the four child relationships; the diff against the unpatched output is the xmlns attribute alone. Building the part from a template string (the COMMENT_XML style) works just as well — the serialized bytes just need to carry the declaration.

2. Worth asserting the namespace in your verification step so this class of miss gets caught.

Everything else checks out; happy to re-review the updated head.

Fixed per review: the created part now carries the OPC namespace declaration. Added root.setAttribute("xmlns", "http://schemas.openxmlformats.org/package/2006/relationships") after the root element.

Re-verified on the new head 903e013:

• The serialized part contains xmlns="http://schemas.openxmlformats.org/package/2006/relationships";
• Namespace-aware parse (ElementTree) resolves the root as {...}Relationships with exactly the four {...}Relationship children, Ids rId1-rId4;
• Id/Type/Target still match _COMMENT_RELS; python -m py_compile clean;
• Existing-rels path untouched (parse-and-append branch unchanged).

Re-verified at head 903e013 — the created part now carries the declaration. Same two-state check as before, run against both heads locally:

• ✅ Created-from-scratch: the part now serializes with xmlns="http://schemas.openxmlformats.org/package/2006/relationships"; xmllint --noout --schema office/schemas/ecma/fouth-edition/opc-relationships.xsd → rc 0. On the pre-fix head ff947c15 the same part comes out at 602 bytes without the declaration and fails with rc 3 ("No matching global declaration"), with ElementTree resolving Relationships un-namespaced and 0 child relationships — so the added line is load-bearing (671 vs 602 bytes = the attribute).
• ✅ Namespace-aware parse: the root resolves as {…relationships}Relationships with exactly the four {…}Relationship children rId1–rId4.
• ✅ Rerun is byte-stable; the existing-rels branch is untouched: appends after the existing rId1 styles relationship (rId2–rId5), original preserved, still validates.
• ✅ python -m py_compile clean.

All good from my side — thanks for the quick turnaround.