Migration: Vox 0.5 → 0.6

Migration: Vox 0.5 → 0.6

This guide lists every language-surface change between Vox 0.5.x and 0.6.0 that requires action in user code, in dependency order. For per-PR detail see CHANGELOG.md [0.6.0]; for the architectural backdrop see the v0.6 acceptance suite and the stdlib gap audit.

Removed surface

@endpoint(kind: …) decorator → bare keywords

Status: removed in v0.6.0 (vox-stdlib-gap-audit-2026-05-23.md §Phase H step 18).

The @endpoint(kind: server|query|mutation) decorator no longer lexes.

Two migrations, not one. @endpoint was first replaced by the at-prefixed decorators @server / @query / @mutation (Phase B, audit doc §11.2, 2026-05-23). Those were themselves retired on 2026-06-30 (cd7cc96874) and are now hard parse errors. If you are coming from v0.5, migrate straight to the bare keywords below — do not stop at the at-prefixed forms.

The canonical surface is a bare keyword in declaration-head position, with no @ and no fn. All three produce the same Decl::Endpoint AST node; nothing changed in HIR, codegen, or runtime semantics.

Retired (≤ v0.5)	Also retired (2026-06-30)	Canonical
@endpoint(kind: server) fn h(...) {}	@server fn h(...) {}	server h(...) to T { }
@endpoint(kind: query) fn h(...) {}	@query fn h(...) {}	query h(...) to T { }
@endpoint(kind: mutation) fn h(...) {}	@mutation fn h(...) {}	mutation h(...) to T { }

Migration recipe (mechanical):

@endpoint(kind: server)
fn list_items() to List[Item] {
server list_items() to List[Item] {
    return db.Item.all()
}

The retired/decorator-usage lint runs before the parser and surfaces a Severity::Error finding with the suggested replacement, so any remaining @endpoint text in your code is flagged at audit time with the friendly migration message rather than at parse time as an unknown token.

Json::get_str / Json::get_int → strict-Option Json API

Status: retired in v0.6.0 (Phase 1 — P1-T2 in the mesh SSOT).

The legacy fallible-Option Json accessors returned Option[Str] / Option[Int] but discarded the path being looked up. The new strict-Option API has two layers:

• Path navigation: get(field: Str), at(index: Int), pointer(rfc6901: Str) — all return Option[Json].
• Type coercion: as_str(), as_int(), as_float(), as_bool(), has(field: Str).

Migration recipe:

let name: Option[Str] = response.get_str("name")
let name: Option[Str] = response.get("name")?.as_str()

let count: Option[Int] = response.get_int("count")
let count: Option[Int] = response.get("count")?.as_int()

For nested paths use pointer (RFC 6901):

fn read_username(payload_json: str) to Option[str] {
    return match std.json.parse(payload_json) {
        Ok(data) => data.pointer("/user/profile/username").and_then(fn(j: Json) to Option[str] { j.as_str() })
        Error(_) => None
    }
}

New surface

@json_as(MyType) typed JSON deserialization (Phase M)

Status: added in v0.6.0.

@json_as(MyType) annotates a type declaration; the compiler synthesises from_json and to_json HirFns on the type so callers can deserialise incoming JSON straight into the user-defined shape instead of threading Json through inference.

@json_as(User)
type User {
    id: Int
    name: Str
}

Additional field-level attributes for use inside the annotated type:

• @field_name("snake_case_name") — JSON name override
• @default(value) — default if the field is missing
• @skip_if_none — omit the field from serialization when None

See docs/src/architecture/rfc-json-as-2026-05-24.md (planned) for the design rationale.

Raw strings r"…" and hash-padded r#"…"#

Status: added in v0.6.0 (docs/src/architecture/v0.6-core-ssot.md raw-string subsection).

Raw string literals do not process escape sequences. Hash-padded form r#"…"# lets the literal contain " characters.

fn demo_raw_strings() {
    let path = r"C:\Users\me\Documents"
    let regex = r#"^([a-z]+):"([^"]+)"$"#
}

Intra-project imports (import "./relative.vox")

Status: added in v0.6.0 (Phase 1 — P1-T1).

import "./foo.vox" resolves a sibling .vox file at runtime under vox run --mode interp. Combined with pub fn, this gives Vox a real module system without the build-system overhead.

src/util.vox

// vox:skip -- cross-file example; multi-file import typecheck differs from in-file lookup as of v0.6
pub fn slugify(s: Str) to Str {
    return s.to_lower().replace(" ", "-")
}

// src/main.vox
import "./util.vox"
fn main() {
    print(slugify("Hello World"))   // -> "hello-world"
}

Caveat: --mode script parity and full typecheck of imported symbols are tracked as v0.7 work; the runtime resolver in --mode interp is the v0.6 deliverable. (The example above is // vox:skip’d because cross-file typecheck of imported Str differs from in-file lookup as of v0.6.)

Changed semantics

Typed list subscript: list[i] returns Option[T]

Status: changed in v0.6.0 (was: bounds-panic in v0.5).

Indexing a typed list with [i] previously evaluated to T and panicked at runtime when i was out of range. v0.6 makes the operation total: list[i] returns Option[T], forcing callers to handle the missing case.

let first: Item = items[0]               // panics if items is empty
let first: Option[Item] = items[0]       // forces explicit handling
if let Some(item) = first {
    // ...
}

The // vox:skip comments in the diff snippets above mark them as illustrative migrations rather than parseable modules; the surrounding text describes the semantics.

This change is consistent with the strict-Option Json API and with dict[k] semantics elsewhere in the stdlib.

Workspace / runtime changes

These don’t affect Vox-language source but matter for tool/IDE/integrator code:

Area	Change
Workspace version	0.5.0 → 0.6.0. All crates inherit via [workspace.package].
vox-db schema baseline	BASELINE_VERSION = 67 (all P3-T1 schema migrations applied).
Dashboard route convention	/api/v2/<surface> REST + /v1/ws topic-multiplex WS (mesh SSOT §5.6).
Unified Task Hopper	New InMemoryHopper in vox-orchestrator (Hp-T1..T4); HTTP intake at /api/v2/hopper/*.
PrioritySource enum	Developer(2) > Orchestrator(1) > LearningPolicy(0); dominance via Ord (Hp-T3).
DeveloperOverride token	reprioritize now requires a capability token minted by DeveloperOverrideMint (Hp-T4).
ACI envelope default	OrchestratorConfig::agentos_aci_envelope_enabled defaults to true (CR-L5).
Effect-row enum	Adds GpuCompute and Mutate variants (P1-T6; prerequisite for MENS distributed training).
Telemetry unification (A–D)	New vox-telemetry L1 facade with TelemetryEvent / TelemetryRecorder; VOX_TELEMETRY master switch; vox telemetry doctor.

Related

• CHANGELOG.md — release-level diff.
• ref-decorators.md — current decorator registry.
• vox-stdlib-gap-audit-2026-05-23.md §Phase H — the soak-gated retirement procedure for @endpoint.
• session-handoff-2026-05-25-finalization-pass.md — v0.6 acceptance criteria, fully green at tag time.