Lyric

What changed in v4.3.2 — 2026-09-03

Round 5 of the sweep, aimed at 4.3's ownership rebuild and at the specification's own sentences. Four findings in the toolchain and two in the documents; the heaviest is again in what the release before it built.

Fixed

• Disposing a VM while its guest is still running no longer throws, and strands nothing.

  A host may do this, and for one case it is the only thing it can do: a guest parked in a blocking wait is out of reach of an ExecutionBudget, which runs on the guest's own thread. 4.3.0 moved the descriptor tables to the VM and left them plain dictionaries, so that host got two wrong answers instead. Measured over 60 rounds: Dispose threw InvalidOperationException out of its own enumeration 53 times, and 55 rounds left a handle stranded past a second Dispose — two of them with no exception at all, which is a handle published into a table Dispose had already emptied.

  The tables take a lock, and acquisition publishes under it: if the VM went while a file or socket was being opened, the call closes what it opened and answers its own "could not", the same refusal it gives when the VM was already disposed.

• A disposed VM no longer hands the host a raw SocketException. The descriptors under poll's select are closed by Dispose, and the select throws when they are. Nothing caught it, so a host that disposed a parked VM got a System.Net.Sockets failure in the platform's own language, across an API whose every other failure is a ScriptException. The wait now ends with the clock alone: the next turn finds those descriptors gone and the reads give the waiter the ordinary failure they always gave.

• Destructuring a struct in a match says so instead of blaming a name. The form is sema-complete — field types bound, irrefutability computed — and the lowering half was never built. It did not say that: the bindings were simply not emitted, so the first USE of one failed as reference to 'x' (only parameters, locals and constants), a message about a name that only looks undeclared. It is now LYR-IR0001: destructuring a struct or class in a match. Enum destructuring is untouched — it is the form the specification gives meaning to.

• The debug adapter refuses a second launch instead of overwriting its session and stranding the first debuggee's sockets, children and files. No client should send one; that is why the adapter must not be the one to leak when it happens.

Documentation

• The specification stopped contradicting itself. spec/02-grammar.md §3.5 said an interface's parent list "holds at most one entry" — false since 2.16, and said the other way round in §5.2 of the same document, in the conformance suite, and in the compiler's own comment. Corrected upstream (lyriclang/lyric-spec#30) and mirrored here. No rule changed and no case moved, so the suite pin stays at 4.0.

• The README stopped promising the REPL forgets. It said "declarations persist across entries; statements run once". What persists is the declaration, and the session re-runs everything it has accumulated on every entry — so a declaration whose initializer has an effect repeats that effect once per entry. Measured: four entries, four executions.

The full changelog →