The patch forks createOutputTransformStream: output==null skips partialOutput
(the OOM fix, already tested), output!=null preserves the original cumulative
accumulation. Only the skip branch was tested; the preserve branch — on which the
patch's "byte-identical when an output strategy is set" safety claim rests — had no
coverage, so a future re-port (patches are re-created via `pnpm patch` on every ai
bump) could silently route output-set calls into the skip branch and leave
partialOutput empty for object/text-output consumers, uncaught.
Add a 4th test: streamText({ ..., experimental_output: Output.text() }), drain
textStream, collect experimental_partialOutputStream, and assert it is non-empty and
cumulative (last partial == full text "Hello, world!"). Reuses the existing
makeModel() harness. Verified on the patched dist: partials are
["Hello","Hello, ","Hello, world!"]. `npx jest ai-sdk-partial-output.patch.spec.ts`
→ 4 passed.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
agent_coder
d8fc724d90