`_normalize_ts_import_types` filtered each `import(...)` regex match against
every tree-sitter `type_arguments` byte range with a nested linear scan, in
both the pre-mask and post-mask passes:
matches = [m for m in matches
if not any(start <= m.start() < end
for start, end in original_type_ranges)]
That is O(matches x ranges), and `m.start()` is re-evaluated inside `any()`
for every range — which is why profiles blamed `re.Match.start`/`_sre` and
`sample` appeared to show a pathological regex. The regexes are all linear;
the quadratic caller was the real cost.
Both counts grow with file size in TypeScript that mixes generic calls
(`fn<A, B>(x)` — one `type_arguments` range each) with `import(...)` types,
which is the shape of generated and barrel modules in a large monorepo. On
the filter alone: a 0.8MB/10k-import file took ~21s, 2.1MB/25k ~2.6min, and
4.2MB/50k ~11.8min. With several such files `extract` never finished, and a
worker sat at 100% CPU holding no open files because the work is entirely
in-memory after the read.
Replace both scans with a binary search over start-sorted ranges plus a
prefix-maximum of `end` values, so a lookup touches nesting depth rather
than every range. Type-argument ranges nest but never partially overlap, so
the prefix maximum is a correct stop condition; a *closed* inner sibling
must not terminate the leftward walk, which a naive running-max break gets
wrong. Verified against the old predicate with 500k differential cases,
including non-nested random ranges: zero mismatches.
Normalization output is unchanged — byte-length and line-count preserving,
same masking decisions, and the runtime-vs-type disambiguation from 6baa5e0
still holds.
Also restore the emptiness guard in the second pass: the range list is now
an index tuple, which is always truthy, so it checks the spans it holds.
The new test asserts on scaling (2x input must not ~4x the time) rather than
wall-clock, so it is not machine-dependent. It fails at ~3.4x before this
change and passes after.
(cherry picked from commit b662361d8b)
Sagexd08
1dcb1e1f3a