feat(ci): swap Python's JUnit XML parser for the native Rust parser

[jd]

First layer of the mergify ci junit-process port — replace the
Python xml.etree.ElementTree walk in
mergify_cli/ci/junit_processing/junit.py with a call into a
new hidden Rust subcommand, mergify _internal junit-parse <FILE>,
that exposes the parser as JSON.

The Rust parser mirrors the Python implementation's accepted
dialect: <testsuites> root with nested <testsuite> children,
a bare <testsuite> root, or a <testsuite> root with nested
descendants. Within each suite, every <testcase> becomes a
typed TestCase tagged with its result and (for failures and
errors) the kind/message attributes plus the body text from the
first <failure> / <error> child.

quick-xml 0.40 splits text events around each entity reference,
so the parser accumulates body content across Text, CData,
and GeneralRef events into a per-failure buffer and trims once
at the closing tag — anything else would silently lose the chunk
before the first > / < / &.

The subcommand emits a JSON object
{"suite_names": [...], "cases": [...]} — suite_names lists
testsuites in document order (ancestors before descendants,
matching Python's findall(".//{*}testsuite") walk), cases is
a flat array of typed test cases each tagged with the closest
enclosing suite name. The Python side now iterates suite_names
to build one suite span per entry and looks up cases in a dict
keyed by suite_name — preserving the nested-suite ordering the
old ET walk produced.

This is a transitional bridge. When Phase C of the port lands
later in the stack (the native ci junit-process orchestrator
that subsumes the entire command), the Python side of
junit-process and the _internal junit-parse subcommand
both go away. Cleanup checklist for that follow-up:

• delete Subcommands::Internal, InternalSubcommand,
  InternalJunitParseArgs, NativeCommand::InternalJunitParse,
  and the ("_internal", "junit-parse") entry in NATIVE_COMMANDS
• delete the Serialize derive + serialize_duration_secs helper
  on the parser types (only needed for the JSON wire format)
• drop the serde_json dep on mergify-cli
• delete mergify_cli/ci/junit_processing/junit.py (or strip
  it down to the orchestrator pieces Phase C still needs)

Co-Authored-By: Claude Opus 4.7 noreply@anthropic.com

[jd]

This pull request is part of a Mergify stack:

#	Pull Request	Link
1	feat(ci): swap Python's JUnit XML parser for the native Rust parser	#1465	👈
2	feat(ci): swap Python's OTLP encode+upload for the native Rust pipeline	#1466
3	feat(ci): promote ci junit-process and its junit-upload alias to native Rust	#1467

[mergify]

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[jd]

Revision history

#	Type	Changes	Reason	Date
1	initial	380699c		2026-05-27 08:27 UTC
2	rebase	380699c → aaf35b0 (rebase only)		2026-05-27 08:27 UTC
3	rebase	aaf35b0 → 1dcc6df (rebase only)		2026-05-27 08:46 UTC
4	rebase	1dcc6df → 4778d48 (rebase only)		2026-05-27 10:04 UTC
5	rebase	4778d48 → e338014 (rebase only)		2026-05-27 10:15 UTC
6	content	23bd8a0 → 63399a1 (raw)	Refactored Phase A from 'add Rust parser as library code (inert until Phase C)' into 'swap Python's XML parser for the native Rust parser via a hidden _internal junit-parse subprocess bridge'. Now …	2026-05-28 09:45 UTC
7	content	63399a1 → 73fc577 (raw)	Switch the JUnit parser's text-event decoding from quick-xml's plain decode() to xml10_content() so CRLF line endings get normalized to LF per the XML 1.0 spec. Python's xml.etree.ElementTree did thi…	2026-05-29 06:35 UTC
8	rebase	73fc577 → 64fccaf (rebase only)		2026-05-29 08:31 UTC
9	rebase	64fccaf → f6a515e (rebase only)		2026-05-29 11:32 UTC

[mergify]

@jd this pull request is now in conflict 😩

[mergify]

Merge Queue Status

• ✅ Entered queue — 2026-05-29 13:44 UTC · Rule: default
• ✅ Checks passed · on draft merge queue: embarking main (2bb98f0) and #1465 together #1487
• ✅ Merged — 2026-05-29 14:00 UTC · at f6a515e356f723a24531ebbeee03e61f24b41be8 · squash

This pull request spent 16 minutes 14 seconds in the queue, including 15 minutes 28 seconds running CI.

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