fix(Stream): avoid mutable Channel.runFold accumulator in mkUint8Array by stephanschielke · Pull Request #2127 · Effect-TS/effect-smol

stephanschielke · 2026-05-06T06:33:50Z

What

Stream.mkUint8Array was refactored in 4.0.0-beta.59 to use Channel.runFold with a mutable accumulator (acc.bytes +=, acc.arrays.push). In Bun --compile --minify binaries, mutating an object that is passed repeatedly as the accumulator to a fold step callback throws Attempting to define property on object that is not extensible.

This does NOT reproduce with:

bun run (interpreted mode)
bun build --compile without --minify
Any Node.js runtime

Fix

Revert to the pre-beta.59 immutable Channel.runFold pattern where each fold iteration returns a new Uint8Array instead of mutating a shared { bytes, arrays } object. This matches the established convention used by Multipart.collectUint8Array (line 472) and what mkUint8Array itself used before beta.59.

Verification

All commands run from the repo root:

pnpm --filter effect check -- zero type errors
pnpm lint-fix -- zero warnings, zero errors
pnpm --filter effect test run -- Stream.test.ts -- all Stream tests pass. 7 pre-existing failures in unrelated files (EffectKeepAlive, Command, OtlpMetrics) -- same count on upstream/main without this change.

Tests

Added three tests for mkUint8Array:

basic concatenation across two chunks
many-chunk regression (10 single-byte chunks -- the exact failing scenario)
empty stream edge case

Real-world impact

opencode v1.14.34+ crashes on every second LLM tool call in compiled binaries because snapshot/index.ts calls Stream.mkUint8Array(handle.stdout) to collect git cat-file --batch output. See anomalyco/opencode#25873 and anomalyco/opencode#25867.

Note

Stream.runCollect (line 9907) also mutates its fold accumulator (acc.push(chunk[i])). It may be affected by the same Bun compiled-mode behavior. Not fixing here to keep this PR focused on the confirmed crash site.

changeset-bot · 2026-05-06T06:33:54Z

🦋 Changeset detected

Latest commit: 6d88699

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 27 packages

Name	Type
effect	Patch
@effect/opentelemetry	Patch
@effect/platform-browser	Patch
@effect/platform-bun	Patch
@effect/platform-node-shared	Patch
@effect/platform-node	Patch
@effect/vitest	Patch
@effect/ai-anthropic	Patch
@effect/ai-openai-compat	Patch
@effect/ai-openai	Patch
@effect/ai-openrouter	Patch
@effect/atom-react	Patch
@effect/atom-solid	Patch
@effect/atom-vue	Patch
@effect/sql-clickhouse	Patch
@effect/sql-d1	Patch
@effect/sql-libsql	Patch
@effect/sql-mssql	Patch
@effect/sql-mysql2	Patch
@effect/sql-pg	Patch
@effect/sql-pglite	Patch
@effect/sql-sqlite-bun	Patch
@effect/sql-sqlite-do	Patch
@effect/sql-sqlite-node	Patch
@effect/sql-sqlite-react-native	Patch
@effect/sql-sqlite-wasm	Patch
@effect/openapi-generator	Patch

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stephanschielke · 2026-05-06T07:35:49Z

Note on CI: there are 7 pre-existing test failures on main that are unrelated to this change:

test/EffectKeepAlive.test.ts (2 failures -- timing assertions)
test/unstable/cli/Command.test.ts (4 failures -- toMatchInlineSnapshot context error)
test/unstable/observability/OtlpMetrics.test.ts (1 failure -- gauge delta assertion)

Verified locally by running the test suite on upstream/main without this change -- same 7 failures. With this change, the count stays at 7 (zero regressions introduced).

github-actions · 2026-05-07T06:09:45Z

📊 JSDoc Documentation Analysis

📈 Current Analysis Results

Analyzing 136 TypeScript files in packages/effect/src/ (including schema and config subdirectories)...

============================================================
         EFFECT JSDOC ANALYSIS REPORT
============================================================

📊 SUMMARY STATISTICS
------------------------------
Total files analyzed: 136
Total exported members: 4318
Missing @example: 2184 (50.6%)
Missing @category: 397 (9.2%)

🎯 TOP FILES NEEDING ATTENTION
----------------------------------------
1. Schema.ts
   📝 520 missing examples, 🏷️  203 missing categories
   📦 520 total exports
2. Array.ts
   📝 135 missing examples, 🏷️  2 missing categories
   📦 140 total exports
3. SchemaRepresentation.ts
   📝 96 missing examples, 🏷️  12 missing categories
   📦 96 total exports
4. SchemaAST.ts
   📝 77 missing examples, 🏷️  21 missing categories
   📦 77 total exports
5. Cause.ts
   📝 79 missing examples, 🏷️  2 missing categories
   📦 79 total exports
6. Channel.ts
   📝 81 missing examples, 🏷️  0 missing categories
   📦 152 total exports
7. SchemaTransformation.ts
   📝 43 missing examples, 🏷️  31 missing categories
   📦 43 total exports
8. Option.ts
   📝 66 missing examples, 🏷️  3 missing categories
   📦 66 total exports
9. Sink.ts
   📝 64 missing examples, 🏷️  2 missing categories
   📦 81 total exports
10. Predicate.ts
   📝 57 missing examples, 🏷️  0 missing categories
   📦 57 total exports
11. SchemaGetter.ts
   📝 51 missing examples, 🏷️  0 missing categories
   📦 51 total exports
12. Result.ts
   📝 46 missing examples, 🏷️  0 missing categories
   📦 46 total exports
13. Config.ts
   📝 35 missing examples, 🏷️  6 missing categories
   📦 35 total exports
14. Types.ts
   📝 39 missing examples, 🏷️  0 missing categories
   📦 39 total exports
15. Effect.ts
   📝 32 missing examples, 🏷️  2 missing categories
   📦 255 total exports

✅ PERFECTLY DOCUMENTED FILES
-----------------------------------
   Chunk.ts (86 exports)
   Clock.ts (5 exports)
   FiberHandle.ts (15 exports)
   FiberMap.ts (19 exports)
   FiberSet.ts (14 exports)
   HKT.ts (4 exports)
   HashMap.ts (44 exports)
   HashSet.ts (21 exports)
   Match.ts (57 exports)
   MutableRef.ts (17 exports)
   NonEmptyIterable.ts (3 exports)
   Random.ts (9 exports)
   Redacted.ts (9 exports)
   RegExp.ts (3 exports)
   Symbol.ts (1 exports)
   Trie.ts (29 exports)
   TxChunk.ts (22 exports)
   TxDeferred.ts (7 exports)
   TxHashMap.ts (41 exports)
   TxHashSet.ts (24 exports)
   TxPriorityQueue.ts (19 exports)
   TxReentrantLock.ts (17 exports)
   TxRef.ts (7 exports)
   TxSemaphore.ts (14 exports)
   TxSubscriptionRef.ts (12 exports)
   Unify.ts (8 exports)
   index.ts (0 exports)

🔍 SAMPLE MISSING ITEMS FROM Schema.ts
-----------------------------------
   Optionality (type, line 150): missing example, category
   Mutability (type, line 159): missing example, category
   ConstructorDefault (type, line 169): missing example, category
   MakeOptions (interface, line 183): missing example, category
   Bottom (interface, line 211): missing example, category
   declareConstructor (interface, line 269): missing example
   declareConstructor (function, line 333): missing example
   declare (interface, line 360): missing example
   declare (function, line 393): missing example
   revealBottom (function, line 433): missing example, category

📋 BREAKDOWN BY EXPORT TYPE
-----------------------------------
const: 1126 missing examples, 114 missing categories
interface: 346 missing examples, 91 missing categories
type: 253 missing examples, 79 missing categories
function: 353 missing examples, 93 missing categories
namespace: 48 missing examples, 20 missing categories
class: 58 missing examples, 0 missing categories

📈 DOCUMENTATION PROGRESS
------------------------------
Examples: 2134/4318 (49.4% complete)
Categories: 3921/4318 (90.8% complete)

============================================================
Analysis complete! 2581 items need attention.
============================================================

📄 Detailed results saved to: jsdoc-analysis-results.json

This comment is automatically updated on each push. View the analysis script for details.

github-actions · 2026-05-07T06:09:52Z

Bundle Size Analysis

File Name	Current Size	Previous Size	Difference
`basic.ts`	6.73 KB	6.72 KB	+0.00 KB (+0.03%)
`batching.ts`	9.23 KB	9.23 KB	+0.00 KB (+0.02%)
`brand.ts`	6.45 KB	6.45 KB	0.00 KB (0.00%)
`cache.ts`	9.99 KB	9.99 KB	+0.00 KB (+0.01%)
`config.ts`	18.45 KB	18.45 KB	+0.01 KB (+0.03%)
`differ.ts`	16.88 KB	16.88 KB	+0.01 KB (+0.03%)
`http-client.ts`	20.20 KB	20.20 KB	+0.00 KB (+0.01%)
`logger.ts`	10.20 KB	10.20 KB	+0.00 KB (+0.01%)
`metric.ts`	8.57 KB	8.57 KB	+0.00 KB (+0.05%)
`optic.ts`	7.61 KB	7.61 KB	0.00 KB (0.00%)
`pubsub.ts`	14.10 KB	14.10 KB	+0.00 KB (+0.01%)
`queue.ts`	11.09 KB	11.09 KB	+0.00 KB (+0.02%)
`schedule.ts`	10.31 KB	10.31 KB	+0.01 KB (+0.05%)
`schema-representation-roundtrip.ts`	26.19 KB	26.19 KB	+0.00 KB (+0.01%)
`schema-string-transformation.ts`	12.62 KB	12.61 KB	+0.01 KB (+0.05%)
`schema-string.ts`	10.36 KB	10.36 KB	+0.00 KB (+0.03%)
`schema-template-literal.ts`	13.98 KB	13.97 KB	+0.00 KB (+0.03%)
`schema-toArbitraryLazy.ts`	18.51 KB	18.51 KB	+0.01 KB (+0.03%)
`schema-toCodeDocument.ts`	21.19 KB	21.18 KB	+0.00 KB (+0.01%)
`schema-toCodecJson.ts`	17.75 KB	17.75 KB	+0.01 KB (+0.03%)
`schema-toEquivalence.ts`	17.68 KB	17.68 KB	+0.00 KB (+0.02%)
`schema-toFormatter.ts`	17.52 KB	17.52 KB	+0.00 KB (+0.02%)
`schema-toJsonSchemaDocument.ts`	20.03 KB	20.03 KB	+0.00 KB (+0.01%)
`schema-toRepresentation.ts`	18.08 KB	18.08 KB	+0.00 KB (+0.02%)
`schema.ts`	17.09 KB	17.08 KB	+0.01 KB (+0.03%)
`stm.ts`	11.97 KB	11.96 KB	+0.01 KB (+0.04%)
`stream.ts`	9.26 KB	9.26 KB	+0.00 KB (+0.04%)

IMax153 · 2026-05-09T08:37:51Z

Closing this PR as the issue is not on our end.

This was referenced May 6, 2026

fix(session): clone tool input before passing to EventV2 to prevent Immer freeze anomalyco/opencode#25867

Open

Stream.mkUint8Array crashes in Bun compiled+minified binaries: mutable Channel.runFold accumulator #2126

Closed

stephanschielke force-pushed the fix/stream-mkuint8array-mutable-fold branch from dab622f to 7ed780a Compare May 6, 2026 07:30

stephanschielke force-pushed the fix/stream-mkuint8array-mutable-fold branch from 7ed780a to b44edfb Compare May 6, 2026 07:36

fix(Stream): avoid mutable Channel.runFold accumulator in mkUint8Array

6d88699

stephanschielke force-pushed the fix/stream-mkuint8array-mutable-fold branch from b44edfb to 6d88699 Compare May 6, 2026 07:45

IMax153 closed this May 9, 2026

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fix(Stream): avoid mutable Channel.runFold accumulator in mkUint8Array#2127

fix(Stream): avoid mutable Channel.runFold accumulator in mkUint8Array#2127
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stephanschielke:fix/stream-mkuint8array-mutable-fold

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