Files
settled-reach/client/scripts/protocol/step_canvas_protocol.gd
T
jpmschweitzerandClaude Fable 5 76d82a6a51 fix(ui): PR #203 review round — total retirement + bin decode + wired reset
Tyre finding: the orphaned AtlasViewer cluster is now actually deleted
(atlas_viewer, atlas_marker_overlay, atlas_descend_geometry,
atlas_legend_panel — a sixth orphan found beyond the review list —
atlas_generation_proxy, atlas_generation_state; ~2,497 lines), with
reachability re-verified across preload/class_name/res:// strings,
every .tscn, and the standalone companion app. Test suites triaged,
not blanket-deleted: 5 pure AtlasOverlayColors tests relocated into
test_atlas_window_colors, the live type-identity regression guard
relocated into test_step_canvas_viewer, dead coverage deleted. A real
harness gap surfaced during diligence and RULED, not patched:
visual_scenarios/visual_capture golden shots call retired
continuous-zoom API — no shim (would resurrect what D-255 kills);
inventory recorded on re-scoped T-1157 (gate-invisible, manual
targets only).

Hoshe finding 1: decode_png_field now detects the [Error,
PackedByteArray] bin-shape from messagepack.gd explicitly — a genuine
msgpack bin payload decodes correctly instead of silently collapsing
to [0,0]; test built from a real round-tripped bin decode.

Hoshe finding 2: the hard zoom-out reset is wired — ascend at rung 0
with a drifted view triggers _reset_to_global (the restored HARD
condition), behavioral tests through the real input path.

Notes folded: refloat + edge-scroll test coverage, legend smoke suite,
Vector2i narrowing-safety comment with computed headroom.

gdlint clean on touched files; full client suite 3364/3364.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-07-25 09:32:52 +02:00

234 lines
12 KiB
GDScript

class_name StepCanvasProtocol
## StepCanvasRequest/StepCanvasResponse wire codec (T-1182, D-255(c)) — the
## stepped Atlas ladder's tagged-envelope carrier, executing the D-225
## migration server/src/atlas/step_canvas.rs already ships (T-1181, PR #201).
## Split out of protocol.gd (not folded in), same rationale as
## browse_protocol.gd/atlas_map_protocol.gd — stay under gdlint's
## max-file-lines, one file per wire-shape family.
##
## `step_canvas: true` is the mandatory discriminator field — the SIXTH
## `Inbound` shape server/src/bridge/mod.rs demuxes on (star_map/city_names/
## browse/step_canvas, plus the two field-shape-disambiguated map probes).
##
## **Wire shapes (confirmed against server/src/atlas/step_canvas.rs, the
## authoritative source over any doc drift — T-1181's IMPLEMENTATION REPORT +
## WIRE SHAPE ADDENDUM, 2026-07-25):**
## StepCanvasRequest — a map: {step_canvas: true, body_id: String,
## rung: <bare string, one of "Global"|"Region"|"District"|"Quarter"|
## "Block"|"Chunk">, center: [i64, i64], extent: [u32, u32],
## min_wl_m: u32}. `rung` is a unit-variant enum, encoded as its Rust
## variant NAME verbatim (rmp_serde's bare-enum convention, same as
## granularity_v2/RoadNodeKind/CourseTerminus elsewhere on this wire).
## `center`/`extent` are meaningless for Global (server ignores extent
## entirely, center is echoed but unused) but are still sent — the
## request shape carries them unconditionally, no per-rung omission (the
## server-side struct has no Option on either field).
## StepCanvasResponse — a map: {body_id, rung, center: [i64,i64],
## extent: [u32,u32], min_wl_m: u32, status, canvas: null | EncodedStepCanvas}.
## `extent` is the server-CLAMPED echo (PR #201 review) — ALWAYS read
## this back, never assume the requested extent; `(0,0)` for Global (the
## wire extent is never read for that rung, so there is no clamped value
## to report). `status` is the same bare-string-or-{"Error":"msg"} shape
## every other status enum on this wire uses (Ready|Pending|NotFound|
## Error(String)) — decoded via the shared _decode_status_field() shape
## (duplicated here per browse_protocol.gd's own "genuinely standalone"
## precedent, not shared via a Callable).
## EncodedStepCanvas — a map: {width, height, morphology, elev_q, temp_dc,
## moisture_q, vegetation, settlement_id, glaciation, flooded_q, courses,
## cliffs}. The six PNG-per-field dense planes (morphology/elev_q/
## moisture_q/vegetation/glaciation/flooded_q) are each a map
## {"png_bytes": [...]} — png_bytes is a Rust `Vec<u8>` with NO
## serde_bytes annotation anywhere in this codebase (confirmed: grep for
## serde_bytes across server/src returns nothing), so serde's blanket
## Vec<T> impl serializes it via serialize_seq — a msgpack ARRAY of
## small-integer elements, NOT a `bin` blob. messagepack.gd's decoder
## therefore returns a plain GDScript Array (one int per byte), which
## this codec repacks into a PackedByteArray via the direct
## PackedByteArray(array) constructor before handing it to
## Image.load_png_from_buffer() — decode_png_field() below is the one
## place this conversion happens. temp_dc/settlement_id are the OTHER
## two dense fields, shipped raw MessagePack-native (too wide for an
## 8-bit PNG plane per EncodedTempField/EncodedSettlementField's own
## server-side doc): {"values": [...]} — i16/u32 arrays respectively,
## passed through as plain Arrays, no PackedByteArray repack (their
## per-cell domain doesn't fit a byte anyway). courses/cliffs are sparse
## MessagePack-native lists, passed through unshaped (the annotation
## layer owns interpreting RiverCourse/CliffSegment's own per-entry
## shape, matching atlas_map_protocol.gd's existing "raw passthrough,
## caller reshapes" precedent for district_window's courses field).
## Encode a StepCanvasRequest. `mp` is the loaded messagepack.gd module
## (passed in rather than reloaded here, matching every other codec in this
## cluster). `rung` is one of the six bare-string rung tags
## (StepCanvasTransport.RUNG_* constants) — sent verbatim, no client-side
## validation (the server rejects an unrecognized variant name at decode
## time per step_canvas.rs's own doc: "Unknown -> rejected, never trusted
## from the wire").
static func encode_step_canvas_request(
mp, body_id: String, rung: String, center: Vector2i, extent: Vector2i, min_wl_m: int = 0
) -> PackedByteArray:
var msg := {
"step_canvas": true,
"body_id": body_id,
"rung": rung,
"center": [center.x, center.y],
"extent": [extent.x, extent.y],
"min_wl_m": min_wl_m,
}
var result = mp.encode(msg)
if result.status != null:
push_error("StepCanvasProtocol: encode_step_canvas_request failed: %s" % result.status)
return PackedByteArray()
return result.value
## Shared status-enum decode — bare string ("Ready"/"Pending"/"NotFound") or
## a single-key map ({"Error": "message"}) for the one data variant. Same
## shape browse_protocol.gd/atlas_map_protocol.gd already implement for their
## own status enums; duplicated here rather than shared via a Callable to
## keep this file genuinely standalone (browse_protocol.gd's own stated
## rationale for its copy).
static func _decode_status_field(status_raw: Variant) -> Dictionary:
if status_raw is String:
return {"status": status_raw, "error": ""}
if status_raw is Dictionary and status_raw.has("Error"):
return {"status": "Error", "error": str(status_raw["Error"])}
return {"status": "", "error": ""}
## Repack a decoded {"png_bytes": ...} field into a PackedByteArray ready for
## Image.load_png_from_buffer(). `field_raw` is the raw decoded Variant for
## one of the six PNG-per-field planes.
##
## **Two possible decoded shapes for `png_bytes`, both handled (PR #203
## review, Hoshe finding 1):**
## 1. **Array of ints** — the shape rmp_serde ACTUALLY produces today (no
## `serde_bytes` anywhere in server/src, confirmed by grep — see this
## file's own header doc): serde's blanket `Vec<u8>` impl serializes via
## `serialize_seq`, a msgpack ARRAY, which messagepack.gd's decoder turns
## into a plain GDScript `Array` of small ints. `PackedByteArray(array)`
## repacks this correctly.
## 2. **`[error: int, data: PackedByteArray]`** — the shape messagepack.gd's
## OWN `bin_8`/`bin_16`/`bin_32` decode path produces
## (`StreamPeerBuffer.get_partial_data()`'s documented `[Error,
## PackedByteArray]` pair), reachable the day the server adds
## `serde_bytes` to `png_bytes` (a `bin`-typed field is a strictly-smaller
## wire encoding for the same bytes, a plausible future optimization this
## codec must not silently mis-decode). **This shape is ALSO `is Array`**
## — it passed the old guard silently. Feeding it straight to
## `PackedByteArray(array)` does NOT error; it coerces each Array element
## to a byte, and a `PackedByteArray` element coerces to `0` (verified
## live: `PackedByteArray([0, PackedByteArray([1,2,3])])` ==
## `PackedByteArray([0, 0])`) — a silent, undetectable byte-loss that
## would corrupt every PNG plane the day this shape appears, with no
## error anywhere in the path (the corrupted bytes still often decode as
## SOME image, just the wrong one).
##
## The fix: detect shape 2 explicitly (`size() == 2`, first element an
## `int`, second a `PackedByteArray`) and return the inner bytes directly —
## checked BEFORE the generic Array repack, so shape 2 never reaches the
## byte-coercion path at all. Any other/malformed input (not a Dictionary,
## no `png_bytes` key, an Array that matches neither shape) returns an empty
## PackedByteArray — the caller's Image decode then fails gracefully, same
## "skip the bad entry" posture the rest of this cluster uses rather than
## crashing on a malformed wire payload.
static func decode_png_field(field_raw: Variant) -> PackedByteArray:
if not field_raw is Dictionary:
return PackedByteArray()
var bytes_raw: Variant = (field_raw as Dictionary).get("png_bytes")
if not bytes_raw is Array:
return PackedByteArray()
var arr: Array = bytes_raw
if arr.size() == 2 and arr[0] is int and arr[1] is PackedByteArray:
return arr[1] # messagepack.gd's bin_8/16/32 [error, data] pair
return PackedByteArray(arr)
## Build an EncodedStepCanvas Dictionary (GDScript-side shape) from an
## already-decoded raw value. Returns null if `raw` isn't a plausible canvas
## (missing width/height). PNG fields are repacked to PackedByteArray here
## (once, at decode time) — every downstream consumer (the terrain layer)
## works with real PackedByteArray/Image objects, never re-touches the raw
## msgpack Array shape.
static func _decode_encoded_canvas(raw: Variant) -> Variant:
if not raw is Dictionary:
return null
var d: Dictionary = raw
if not d.has("width") or not d.has("height"):
return null
var temp_dc_raw: Variant = d.get("temp_dc")
var settlement_id_raw: Variant = d.get("settlement_id")
return {
"width": int(d.get("width", 0)),
"height": int(d.get("height", 0)),
"morphology": decode_png_field(d.get("morphology")),
"elev_q": decode_png_field(d.get("elev_q")),
"temp_dc": (temp_dc_raw as Dictionary).get("values", []) if temp_dc_raw is Dictionary else [],
"moisture_q": decode_png_field(d.get("moisture_q")),
"vegetation": decode_png_field(d.get("vegetation")),
"settlement_id":
(
(settlement_id_raw as Dictionary).get("values", [])
if settlement_id_raw is Dictionary
else []
),
"glaciation": decode_png_field(d.get("glaciation")),
"flooded_q": decode_png_field(d.get("flooded_q")),
"courses": d.get("courses", []),
"cliffs": d.get("cliffs", []),
}
## Build a StepCanvasResponse Dictionary from an already-decoded raw value.
## Returns null unless it carries "rung" AND "status" — "rung" is the field
## no other decoded response on this wire has (atlas/citynames/browse all
## lack it), making it a safe, unambiguous discriminator for
## Protocol.decode_inbound()'s dispatch.
static func step_canvas_response_from_raw(raw: Variant) -> Variant:
if not raw is Dictionary or not raw.has("rung") or not raw.has("status"):
return null
var d: Dictionary = raw
var decoded_status := _decode_status_field(d.get("status"))
var center_raw: Variant = d.get("center", [0, 0])
var extent_raw: Variant = d.get("extent", [0, 0])
return {
"body_id": str(d.get("body_id", "")),
"rung": str(d.get("rung", "")),
"center": _vec_from_pair(center_raw),
"extent": _vec_from_pair(extent_raw),
"min_wl_m": int(d.get("min_wl_m", 0)),
"status": decoded_status["status"],
"error": decoded_status["error"],
"canvas": _decode_encoded_canvas(d.get("canvas")),
}
## Narrows the wire's `center: (i64, i64)` / `extent: (u32, u32)` pairs (both
## StepCanvasResponse fields, step_canvas.rs) into Godot's `Vector2i`, whose
## components are 32-bit signed ints (`int32_t`, range ±2,147,483,647 —
## confirmed against Godot's own `Vector2i` type, not assumed). This
## narrowing is safe under the two invariants both fields actually carry on
## this wire, neither of them the full i64/u32 range in practice:
## - `center` — world-metres. Bounded by the body's own circumference (a
## center coordinate is never meaningfully larger than the body's half
## circumference, `pi * body_radius_km * 1000`): even a Jupiter-class
## body (~70,000 km radius) caps out around 2.2e8 m, three orders of
## magnitude under the int32 ceiling. No real or plausible body in this
## project's scope (`server/data/systems.db`'s body_radius_km column)
## approaches the ~682,000 km radius that WOULD overflow int32 metres.
## - `extent` — canvas cells. Hard-clamped server-side to
## STEP_CANVAS_MAX_EXTENT_AXIS (3,840 per axis, step_canvas.rs's
## `clamp_step_canvas_extent()`) before it ever reaches the wire —
## trivially in range regardless of what a malicious/buggy sender might
## have originally requested (the CLAMPED value is what's echoed, per
## this file's own "extent ECHO rule" doc on StepCanvasResponse).
## A value outside either invariant (a malformed/adversarial frame) still
## narrows via GDScript's own int() truncation rather than erroring — no
## worse than any other wire field this codec trusts once decoded, and no
## production code path can produce one.
static func _vec_from_pair(pair: Variant) -> Vector2i:
if pair is Array and pair.size() >= 2:
return Vector2i(int(pair[0]), int(pair[1]))
return Vector2i.ZERO