The true cause of the black first launch, server-confirmed after four
disproven theories: a stone-cold body answers the FIRST window request
with a whole-response status 'Pending' (only the whole-body cache-hit
branch sets Ready), and on_response()'s very first check — status !=
Ready -> return — swallowed it before the retry machinery could run.
retries stayed 0 forever; the DERIVING state never resolved. Second
connections worked by luck (the first request warms the whole-body
cache, so they read Ready and take the healthy path). Both tile fan-out
AND single-window first-descents were affected — one shared function,
one fix: branch on the outer status first (the atlas_generation_proxy
reference shape): Pending -> retry, Ready -> existing null-window retry,
NotFound/Error -> give up immediately (the principled give-up policy,
replacing the elapsed-retries ceiling).
Hardening in the same round: deterministic exponential backoff (0.5s
doubling, 4s cap) + per-tile stagger (0.1s * index — six tiles retry at
0.5/0.6/0.7/0.8/0.9/1.0s, strictly-increasing asserted, not jittered);
MAX_RETRIES 20->30 (~110s horizon under backoff).
Regressions are wire-accurate by construction: whole-response Pending
(body_id only, no center/n/granularity — verified against the server's
own response construction) delivered through the REAL fan-out
(tile_set._on_atlas_layers_received, never tile.on_response directly),
mirrored at single-window level. Two first-draft tests that passed with
the bug reverted were caught and strengthened before reporting; every
fix and hardening piece revert-verified independently (7+1 failing
tests without them).
Item 1: while zero tiles have arrived, the viewer draws a centered
screen-space 'DERIVING TERRAIN…' label (text_dim role, no new hue),
dropping the instant the first tile lands — a cold wait now reads as
loading, not broken. New has_any_tile_arrived() predicate (distinct
from has_pending_tiles(): both true mid-arrival, tested exactly there).
Item 2: legend re-fit root-caused empirically, two plausible fixes
disproven by trace before the real one: a manually-positioned Control's
size NEVER tracks a shrinking minimum in this parenting shape, and
RichTextLabel.fit_content reports degenerate minimums until laid out at
real width once — so reset must be DEFERRED and run after refill, not
inside clear(). ImplantPanel.reset_to_content_size() (call_deferred),
wired into both legend refresh()es. The load-bearing test compares
size.y to get_minimum_size().y — a size-to-size comparison passed
trivially with both numbers equally stuck (caught on first draft).
Item 3: make atlas now builds the RELEASE server and passes
SR_SERVER_BIN (a cold DEBUG server delivers zero tiles for >10s on a
new body — live-measured — vs 210ms warm; release serves cold in well
under a second). atlas_standalone._server_binary_path() honors the env
override per the SR_PORT two-tier precedent, debug path unchanged
when unset.
All fixes revert-verified; nine suites green collateral-checked;
gdlint clean.
Bug A (zoom reselection dead): select_rung() redesigned from the two-gate
split to a unified per-rung coverage-ceiling walk (MAX_COVERAGE_M,
finest-first) — which also restores District as a reachable rung
(33-131km extent band; the two-gate model had made it structurally
unreachable). Plus the THIRD instance of the PR #191 C1 clamp-mirror bug
class: _maybe_reselect_rung fed the old rung's _held_n raw into the new
rung's request — the server clamped, the held value didn't, every
cross-rung response stale-dropped. Re-clamped at the boundary; the
leaving_tile_mode flag also fixes a stale request-granularity edge case.
Bug B (orbital = whole body): genuine tile-set model. compute_tile_grid
composes ceil-divided Region-tile centers (canonicalized column wrap,
row clamp, Dictionary-set dedup; Lendel = 3x2 = 6 tiles);
AtlasWindowTileSet owns one AtlasWindowRequest per tile (reusing all
tested request/cache/debounce machinery), fans responses out, per-tile
tile_ready — genuinely progressive; the overlay draws arrived tiles as a
mosaic under the one view transform. enter_orbital branches to tile mode
when >1 tile; single-window path unchanged below the coverage ceiling.
E/W wrap at tile seams live-confirmed (col -6400 wraps to 12739). Pole-
row dedup verified correct but flagged honestly as currently-unreachable
defensive logic (no real radius triggers row collision).
All fixes + fallout verified via revert/confirm-fails/restore. Targeted
suites 256/256; gdlint clean; new 20-test tile-set suite.
jpmschweitzer