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Make zero-length stream reads/writes more consistent - #755
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alexcrichton
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Thanks! Before landing this though I'd like to prototype this and see if there's fallout, notably implementing this in Wasmtime and seeing if wit-bindgen's test suite and maybe wasi-libc's passes. I don't find this urgent from my end though, but if someone else wants to see this landed ASAP I can try to prioritize working on that.
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Ok I've prototyped this in bytecodealliance/wasmtime#15094, and my thoughts of maybe-this-will-break-something stemmed from not realizing that this still had an exemption for streams-with-no-type, so I think this should be good to go 👍 |
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This commit updates to handle WebAssembly/component-model#755 to bounds-check zero-length writes on streams so long as a payload type is present.
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This makes pointer alignment/bounds-checking work the same for zero- and non-zero-length reads/writes, as discussed in #750, and also the temporary same-component-instance check, as discussed in #753. This PR doesn't touch streams empty/unit payloads, which was also discussed in #750, because that raises the new question of what happens if there is no
memory(which is allowed to be omitted).