fix: capture <REQ-IF> opening tag without O(N²) tree mutation#217
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It is a great change, I just left a small comment.
_parse_reqif recorded the original <REQ-IF ...> opening tag by removing every child of the parsed root and serializing the emptied root. Removing the CORE-CONTENT child forced libxml2 to reconcile namespaces across the whole detached spec-object subtree, making this O(N²) in the number of spec objects (~two-thirds of total parse time on large files). Serialize a shallow copy of the root (same tag, nsmap, attributes, no children) instead. This is non-destructive and linear; output is byte-identical for pretty-printed inputs.
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fixed. this is an important fix for us. |
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ReqIFParser._parse_reqifrecords the original<REQ-IF …>opening tag (its namespace declarations and attributes) for faithful round-trip unparsing. It did this by deleting every childof the parsed root and serializing the now-empty root. Removing the
CORE-CONTENTchild forcedlibxml2to reconcile namespaces across the entire detached spec-object subtree — O(N²) inthe number of spec objects, accounting for roughly two-thirds of total parse time on large files (tens of minutes at 100k objects).
Fix
Serialize a shallow copy of the root (same tag, nsmap, and attrib, no children) instead of mutating the parsed tree.
lxmlhas no API to serialize an element's opening tag alone, so achildless copy is the linear way to isolate it. This is also non-destructive — it removes the prior side effect of emptying the caller's tree.
Behavior
<REQ-IF .../>to<REQ-IF ...>— the correct form for an opening-tag capture; does not occur inpretty-printed files.
Performance
Full parse_from_string is now linear: ~0.17 s at 20k objects and ~0.35 s at 40k, versus the old capture block alone taking ~14 s and ~84 s.
Tests
Unit 49/49 pass; integration 78/79 (the one failure is an environmental missing
libtidy, unrelated).