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fix(planner): raise WS frame cap above doc cap (fixes sync reconnect loop)

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The Yjs sync WebSocket had MAX_MESSAGE_BYTES = 256 KB (per frame) but
MAX_DOC_BYTES = 5 MB (per session doc). A full-state sync frame carries
the entire doc, so any session doc between 256 KB and 5 MB was allowed to
exist yet could never sync: the client's sync frame tripped the 256 KB
per-frame cap, the server closed it (1008), the client reconnected, resent
the same oversized frame, and looped forever — the UI froze, the connection
flapped Verbunden/Verbinde, and the network tab filled with 101 reconnects.

Real routes hit this fast because the BRouter geometry is stored in the doc:
a 4-waypoint, 77 km cycling route was already 305 KB.

Fix: the per-frame cap must be >= the doc cap (a full-doc sync must fit in
one frame). Set MAX_MESSAGE_BYTES = MAX_DOC_BYTES + 256 KB overhead; the
5 MB doc cap stays the real size/abuse guard. Updated the test that had
codified the inverted ordering.

Verified: planner typecheck + lint clean, yjs-server 9/9, planner suite
183/183.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
This commit is contained in:
Ullrich Schäfer 2026-07-14 08:58:24 +02:00
parent 696ffb7306
commit e34a06ff5a
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2 changed files with 18 additions and 9 deletions
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9
apps/planner/app/lib/yjs-server.test.ts
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@ -52,9 +52,12 @@ describe("countActiveSessions", () => {
});
describe("doc-size caps", () => {
it("MAX_MESSAGE_BYTES + MAX_DOC_BYTES are positive and ordered sanely", () => {
expect(MAX_MESSAGE_BYTES).toBeGreaterThan(0);
expect(MAX_DOC_BYTES).toBeGreaterThan(MAX_MESSAGE_BYTES);
it("the per-frame cap can carry a full-doc sync (message cap >= doc cap)", () => {
expect(MAX_DOC_BYTES).toBeGreaterThan(0);
// A full-state sync frame contains the entire doc, so a per-frame cap
// below the doc cap makes docs between the two sizes unsyncable (reconnect
// loop). The frame cap must be at least the doc cap, plus protocol room.
expect(MAX_MESSAGE_BYTES).toBeGreaterThanOrEqual(MAX_DOC_BYTES);
});
it("docByteSize returns 0 for an unknown session", () => {