Two profile-guided serialize passes (#139, docs/benchmarks.md passes 29-30).
The attribute writer now precomputes the quote character as a String once
per element instead of interpolating a Character into every attribute,
avoiding the grapheme-breadcrumb machinery that repeats twice per attribute
for a value that never changes within an element. Escaping.comment and
processingInstruction's escaping fallback (taken whenever a comment has a
hyphen or PI data has a '?', a case pass 8 could skip past but not speed up)
is rewritten in the same byte-scan bulk-copy shape as passes 23-24, so a
value with one rare trigger no longer pays a full character-by-character
rebuild.
Both are same-observable-behavior changes. The quote change is byte-
identical by construction. The comment/PI rewrite is verified against a new
differential suite that reimplements the original character-loop as an
independent oracle and checks adjacency/trailing/combining-mark cases plus
two 20000-case seeded fuzzes, since a byte match inside a combining-mark
cluster is not, on its own, the bare trigger character. Full local suite
(1925 tests) unchanged.
Measured with interleaved same-state A/B: pass 29 ~1.5% at a 100k-item
corpus; pass 30 ~2x on a dedicated comment/PI micro-benchmark (the standard
corpus has no comment/PI content, so real documents with copyright banners
or hyphenated comment prose see this, not the headline ratio). A same-
session multi-append restructuring attempt measured a clear ~6% regression
and was reverted; a suspected hasInlineContent double-scan was profiled at
~0.2% of samples and not worth a pass. Both outcomes are recorded in
docs/benchmarks.md rather than dropped.
Mihaela Mihaljevic
d359208ff6