Write each element with a plain XMLWriter

[veewee]

Q	A
Type	improvement
BC Break	no
Fixed issues

Summary

XsdTypeXmlElementWriter runs once for every encoded element and opened a new Writer::inMemory() each time. Most of that cost is in the veewee/xml wrapper rather than in XMLWriter. configure() folds an empty pipeline through Iter\reduce, disallow_issues builds a Psl Result, two closures and an IssueCollection even when nothing went wrong, and write() calls a guard function for every yielded value. The 3MB dense encode goes through this about 157k times per call.

This PR adds Soap\Encoding\Xml\Writer\InMemoryXmlWriter, an in-memory XML writer for this package. It takes a callable(XMLWriter): Generator<bool>, opens a fresh XMLWriter::toMemory() per call, runs the builder with an inline false check and returns outputMemory(). It holds no state between calls. XsdTypeXmlElementWriter now delegates to it, and so do SoapEnvelopeWriter, Soap11FaultEncoder and Soap12FaultEncoder, which were the other places building XML through Writer::inMemory(). The builders and the XmlEncoder contract stay as they are.

Same exceptions

Callers can see the old wrapping. Anything thrown inside a builder comes out as a veewee RuntimeException with the original as previous, wrapped once more for each element level it passes through. Libxml errors raised during the write fail it as well. SoapEnvelopeWriter only unwraps one level, so an encoder that relies on this would notice a change. InMemoryXmlWriter replicates Writer::write with disallow_issues without the overhead: the same libxml_use_internal_errors and libxml_clear_errors sequence, the same RuntimeException factories and messages, and an IssueCollection that is only built when there is a failure or a libxml error.

The first commit adds tests for this that pass on main before the writer changes. They now pin that behaviour on InMemoryXmlWriter directly: a throw inside the builder, a false write, an invalid element name, libxml issues with and without a throw, nested writes, and the libxml error state afterwards. XsdTypeXmlElementWriter keeps a thin test, SoapEnvelopeWriterTest still covers an element failure seen from the envelope, and the envelope and both fault encoders have a test that pins their exact output bytes, which passed against the old writer too. The encoded requests and decoded results of the 3MB workloads have the same sha1 before and after.

Speed

Median of 3 interleaved rounds on the same machine, with ext-soap as the noise reference.

workload	main	this PR
3MB encode sparse, stdClass	1.432 s	1.176 s (-17.9%)
3MB encode sparse, classmap	1.579 s	1.326 s (-16.1%)
3MB encode dense, stdClass	0.718 s	0.512 s (-28.6%)
3MB encode dense, classmap	0.726 s	0.539 s (-25.8%)
EncodeBench literal x500	32.30 ms	25.13 ms (-22.2%)
EncodeBench encoded x500	54.79 ms	45.08 ms (-17.7%)
EncodeSparseBench sparse x500	31.64 ms	23.33 ms (-26.3%)
ext-soap encode literal x500	3.73 ms	3.62 ms (-2.9%)

These numbers were measured before the writer moved into InMemoryXmlWriter. A 3MB encode round after the move is within noise of them.

Decode does not go through this writer and stays within 2%.

Summary by CodeRabbit

• Bug Fixes
  • Improved error reporting when XML generation fails, including invalid XML and writer errors.
  • Preserved SOAP fault and envelope output while tightening checks for serialization issues.
• Tests
  • Added coverage for exact SOAP XML output, escaping, and failure handling.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

• Configuration used: defaults
• Review profile: CHILL
• Plan: Advanced
• Run ID: 0eabf7e6-5ef7-4ee1-bf12-faec0bc3af51

📥 Commits

Reviewing files that changed from the base of the PR and between 403a479 and e4c9599.

📒 Files selected for processing: 10

• src/Fault/Encoder/Soap11FaultEncoder.php
• src/Fault/Encoder/Soap12FaultEncoder.php
• src/Xml/Writer/InMemoryXmlWriter.php
• src/Xml/Writer/SoapEnvelopeWriter.php
• src/Xml/Writer/XsdTypeXmlElementWriter.php
• tests/Unit/Fault/Encoder/Soap11FaultEncoderTest.php
• tests/Unit/Fault/Encoder/Soap12FaultEncoderTest.php
• tests/Unit/Xml/Writer/InMemoryXmlWriterTest.php
• tests/Unit/Xml/Writer/SoapEnvelopeWriterTest.php
• tests/Unit/Xml/Writer/XsdTypeXmlElementWriterTest.php

Included review availability: This review used your included allowance. Your plan provides up to 1 included review per hour; 0 remain after this review.

📝 Walkthrough

The change adds InMemoryXmlWriter to generate XML and report writer or libxml errors. SOAP fault encoders, the SOAP envelope writer, and the XSD type element writer now use it. Tests cover output bytes and error handling.

Changes: XML serialization

Layer / File(s)	Summary
In-memory XML writing and error handling src/Xml/Writer/InMemoryXmlWriter.php, tests/Unit/Xml/Writer/InMemoryXmlWriterTest.php	InMemoryXmlWriter returns generated XML and reports callback failures, false write results, and libxml issues. Tests cover exception chaining and restoration of libxml error settings.
Envelope and XSD writer integrations src/Xml/Writer/SoapEnvelopeWriter.php, src/Xml/Writer/XsdTypeXmlElementWriter.php, tests/Unit/Xml/Writer/SoapEnvelopeWriterTest.php, tests/Unit/Xml/Writer/XsdTypeXmlElementWriterTest.php	Both writers use InMemoryXmlWriter. Tests check serialized output and invalid element-name exception chains.
SOAP fault encoder integrations src/Fault/Encoder/Soap11FaultEncoder.php, src/Fault/Encoder/Soap12FaultEncoder.php, tests/Unit/Fault/Encoder/Soap11FaultEncoderTest.php, tests/Unit/Fault/Encoder/Soap12FaultEncoderTest.php	Both fault encoders use InMemoryXmlWriter. Tests assert exact serialized fault output.

Priority: ➖ Normal

Estimated code review effort: 3 (Moderate) | ~25 minutes

Change: Refactor

Merge Risk: ⚪ Minimal · up to e4c95

No actionable merge-blocking issue is established; the change is ready for normal checks.

Pre-merge checks: 4 · 1

Failed checks: 1 warning

Check name	Status	Explanation	Resolution
Docstring Coverage		Docstring coverage is 15.38% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 26 functions across 10 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

Passed checks: 4 passed

Check name	Status	Explanation
Description Check		Check skipped - CodeRabbit’s high-level summary is enabled.
Title check		The title clearly describes the main change: replacing the previous writer setup with a plain XMLWriter-based implementation across XML elements, envelopes, and faults.
Linked Issues check		Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check		Check skipped because no linked issues were found for this pull request.

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