remove graphemeSegments pinning, which is not tree-shakable

.changeset/huge-hotels-ask.md

@@ -0,0 +1,7 @@
+---
+"unicode-segmenter": patch
+---
+
+Removed pinned `graphemeSegments()` in the module scope to make all APIs able to be three-shaken properly.
+
+It was introduced when they all use `graphemeSegments()` as the core. But now they are all have their own loop.

.claude/skills/codspeed-debug/SKILL.md

@@ -12,8 +12,8 @@ CI (`.github/workflows/codspeed.yml`) runs `node benchmark/grapheme/codspeed.js`
 - V8 runs with stability flags (e.g. `--predictable --hash-seed=1`) and the plugin measures roughly: a few warmup calls → forced `gc()` → **one** measured call.
 - Consequence 1: the measured call sees whatever tier the code reached during warmup. The repo defends with a 2000-iteration `beforeAll` warmup in `codspeed.js` — do not remove it.
 - Consequence 2 (the big trap): **forced GC clears weak references embedded in optimized code** (deopt reason: `embedded weak objects cleared` — e.g. hidden-class maps of objects with no live instances), so optimized code deopts right before the measured call, producing phantom regressions up to ~60%.
-  - Defense in `src/grapheme.js`: the pin block stashing a live generator and its first result on `PAIR._keep`, which keeps the segment-object hidden classes strongly reachable across GC. Do not remove it.
-  - A module-scope `const _keep = ...` does NOT work — unreferenced module bindings don't survive module evaluation; the pin must hang off an object that stays reachable (`PAIR`).
+  - `src/grapheme.js` carried a defense against this from #133 to #145: a block stashing a live generator and its first result on `PAIR._keep`, so the segment-object hidden classes stayed strongly reachable across GC. It was removed after measuring it inert on the current (generator-based) code — the deopt it guarded was diagnosed on a class-iterator rewrite that never shipped. If you re-add anything like it, note that a module-scope `const _keep = ...` does NOT work: unreferenced module bindings don't survive module evaluation, so the pin has to hang off an object that stays reachable.
+  - Before re-adding it, measure it properly: a single instrumented call cannot resolve this for `graphemeSegments`, which allocates ~120 objects per call, so whether a scavenge lands inside the measured call swings it ±30%. Run 50 `{ gc(); one call }` cycles under callgrind and subtract a `{ gc() }`-only run of the same shape; that showed 92,965 vs 92,915 instructions per call (0.05%), with the pin making each major GC ~26 k instructions *more* expensive.
 
 ## Local replication recipe
 

README.md

@@ -237,8 +237,8 @@ Since [Hermes doesn't support the `Intl.Segmenter` API](https://github.com/faceb
 
 | Name                                 | Unicode® | ESM? |    Size | Size (min) | Size (min+gzip) | Size (min+br) | Size (min+zstd) |
 |--------------------------------------|----------|------|--------:|-----------:|----------------:|--------------:|----------------:|
-| `unicode-segmenter/grapheme`         | 17.0.0   | ✔️   |   7,851 |      4,911 |           2,351 |         2,134 |           2,402 |
-| `unicode-segmenter/grapheme` (full*) | 17.0.0   | ✔️   |  10,257 |      5,760 |           2,638 |         2,367 |           2,695 |
+| `unicode-segmenter/grapheme`         | 17.0.0   | ✔️   |   7,767 |      4,876 |           2,325 |         2,104 |           2,374 |
+| `unicode-segmenter/grapheme` (full*) | 17.0.0   | ✔️   |  10,173 |      5,725 |           2,607 |         2,322 |           2,668 |
 | `graphemer`                          | 15.0.0   | ✖️   | 410,435 |     95,104 |          15,752 |        10,660 |          15,911 |
 | `grapheme-splitter`                  | 10.0.0   | ✖️   | 122,254 |     23,682 |           7,852 |         4,802 |           6,753 |
 | `@formatjs/intl-segmenter`*          | 17.0.0   | ✖️   | 268,301 |    176,759 |          45,988 |        31,701 |          45,370 |
@@ -255,8 +255,8 @@ Since [Hermes doesn't support the `Intl.Segmenter` API](https://github.com/faceb
 
 | Name                                | Bytecode size | Bytecode size (gzip)* |
 |-------------------------------------|--------------:|----------------------:|
-| `unicode-segmenter/grapheme`        |        15,892 |                 9,012 |
-| `unicode-segmenter/grapheme` (full) |        16,097 |                 9,176 |
+| `unicode-segmenter/grapheme`        |        15,794 |                 8,916 |
+| `unicode-segmenter/grapheme` (full) |        16,003 |                 9,073 |
 | `graphemer`                         |       134,085 |                31,770 |
 | `grapheme-splitter`                 |        63,942 |                19,165 |
 | `@formatjs/intl-segmenter`          |       329,547 |               136,751 |

src/grapheme.js

@@ -437,15 +437,3 @@ export function collectGraphemes(input) {
   result.push(input.slice(index));
   return result;
 }
-
-// Keep one live segmenter and its result reachable so their hidden classes stay strongly referenced.
-// Otherwise a major GC while no segmenter is alive clears the maps embedded weakly in JIT-optimized code,
-// and the next run pays deoptimization and re-learning costs.
-//
-// The instances are stashed on an always-retained module object,
-// since unreferenced module-scope bindings do not survive module evaluation.
-{
-  let keep = graphemeSegments('_');
-  // @ts-ignore intended expando
-  PAIR._keep = [keep, keep.next()];
-}