René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"stream/iter: fromWritable() cache ignores later options","articleBody":"### Version\n\n26.1.0\n\n### Platform\n\n```text\nmacOS 26.4.1\n```\n\n### Subsystem\n\nstream\n\n### What steps will reproduce the bug?\n\n```js\nimport { throws } from \"assert\";\nimport { Writable } from \"stream\";\nimport { fromWritable } from \"stream/iter\";\n\nconst writable = new Writable({\n  highWaterMark: 1,\n  write(chunk, enc, cb) {\n    // Keep the internal buffer full.\n  },\n});\n\n// First call creates and caches the default strict writer.\nfromWritable(writable);\n\n// Bug 1: invalid options are ignored because the cached writer is returned\n// before options are validated.\nthrows(() =\u003e fromWritable(writable, { backpressure: \"invalid\" }), {\n  code: \"ERR_INVALID_ARG_VALUE\",\n});\n\n// Bug 2: later valid options are ignored too. This should create/use a\n// drop-newest writer, but currently returns the cached strict writer.\nconst writer = fromWritable(writable, { backpressure: \"drop-newest\" });\n\nawait writer.write(\"a\");\n\n// Expected: resolves and drops the chunk.\n// Actual: rejects with ERR_INVALID_STATE from strict backpressure.\nawait writer.write(\"b\");\n\nwritable.destroy();\n```\n\n```console\nnode --experimental-stream-iter repro.js\n```\n\n### How often does it reproduce? Is there a required condition?\n\nAlways\n\n### What is the expected behavior? Why is that the expected behavior?\n\nNo assertion failure, second write resolves.\n\n### What do you see instead?\n\nThe invalid option does not throw.\n\nIf you remove the throws() block, the second write rejects as strict backpressure.\n\n### Additional information\n\n_No response_","author":{"url":"https://github.com/trivikr","@type":"Person","name":"trivikr"},"datePublished":"2026-05-13T07:04:26.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":0},"url":"https://github.com/63277/node/issues/63277"}