feat(platform): Phase 878 gossip RPC pull helpers + view diagnostics (v0.8.845)

Non-breaking mesh hardening: pickFirstGuildRpcResponse with shared validation
predicates for audit/digest RPC pulls; buildGuildGossipRpcDiagnosticsSnapshot
on platform view; unify pull-path viaRpc via markRpcResponse across mesh view
and fetch helpers. Default gossip v1 unchanged; fleet v2 cutover deferred.

Tests: test:ci-phase878 (boot gate, unit, view snapshot, method maps, live digest RPC).
Docs: PLATFORM_ROADMAP, PROTOMUX_RPC_MIGRATION, AUTOMATED_TESTING, release notes.

README.md

@@ -92,6 +92,8 @@ Application facade: one `PearcordPlatform` class that wires identity, database,
 
 **Phase 822 (v0.8.789):** Triple-peer topology via `guild-mesh-topology` + `getMeshStabilityStats`. Bundle: `npm run test:ci-phase822`.
 
+**Phase 878 (v0.8.845):** Gossip RPC pull response helpers (`pickFirstGuildRpcResponse`, validation predicates) + view diagnostics (`buildGuildGossipRpcDiagnosticsSnapshot`). Bundle: `npm run test:ci-phase878`.
+
 **Phase 877 (v0.8.844):** View snapshot RPC wire diagnostics via `buildRpcWireViewSnapshot()`; guild sync/member page handlers use shared `markRpcResponse`. Bundle: `npm run test:ci-phase877`.
 
 **Phase 876 (v0.8.843):** Shared `gossip-rpc-pull.js` + `gossip-rpc-handler-map.js` dedupe for all guild gossip RPC pull paths (zero behavior change). Bundle: `npm run test:ci-phase876`.

gossip-rpc-pull.js

@@ -90,6 +90,20 @@ function markRpcResponse (res) {
   return res
 }
 
+/** First matching guild gossip RPC pull response (Phase 878). */
+function pickFirstGuildRpcResponse (responses, predicate) {
+  if (!Array.isArray(responses) || typeof predicate !== 'function') return null
+  return responses.find((r) => r && predicate(r)) || null
+}
+
+function isValidAuditExportArchiveRpcResponse (r) {
+  return Array.isArray(r?.entries) && r.entries.length > 0
+}
+
+function isValidAutomationDigestSnapshotRpcResponse (r) {
+  return typeof r?.body === 'string' && r.body.length > 0
+}
+
 /** Dev/settings snapshot of protomux-rpc opt-in flags (Phase 877). */
 function buildRpcWireViewSnapshot () {
   const {
@@ -108,6 +122,16 @@ function buildRpcWireViewSnapshot () {
   }
 }
 
+/** Guild gossip RPC handler diagnostics for platform view (Phase 878). */
+function buildGuildGossipRpcDiagnosticsSnapshot () {
+  const { listGuildGossipRpcRequestMethodKeys } = require('./gossip-rpc-handler-map')
+  const methods = listGuildGossipRpcRequestMethodKeys()
+  return {
+    guildGossipRpcHandlerCount: methods.length,
+    guildGossipRpcRequestMethods: methods
+  }
+}
+
 module.exports = {
   meshPeerIdHex,
   guildRpcTimeoutsMs,
@@ -117,5 +141,9 @@ module.exports = {
   requestGuildGossipRpcFromPeers,
   matchesGuildRpcTargetMember,
   markRpcResponse,
-  buildRpcWireViewSnapshot
+  pickFirstGuildRpcResponse,
+  isValidAuditExportArchiveRpcResponse,
+  isValidAutomationDigestSnapshotRpcResponse,
+  buildRpcWireViewSnapshot,
+  buildGuildGossipRpcDiagnosticsSnapshot
 }

mixins/runtime/features/platform-audit-archive-rpc-mixin.js

@@ -9,7 +9,9 @@ const {
   guildRpcTimeoutsMs,
   resolveGuildGossipRpcPeerIds,
   prepareGuildGossipRpcSession,
-  requestGuildGossipRpcFromPeers
+  requestGuildGossipRpcFromPeers,
+  pickFirstGuildRpcResponse,
+  isValidAuditExportArchiveRpcResponse
 } = require('../../../gossip-rpc-pull')
 
 const platformAuditArchiveRpcMixin = {
@@ -69,7 +71,7 @@ const platformAuditArchiveRpcMixin = {
       rpcMs,
       wireMs
     })
-    const hit = responses.find((r) => r && Array.isArray(r.entries) && r.entries.length)
+    const hit = pickFirstGuildRpcResponse(responses, isValidAuditExportArchiveRpcResponse)
     return hit || null
   }
 }

mixins/runtime/features/platform-audit-automation-export-mixin.js

@@ -27,6 +27,7 @@ const {
   buildActivityFeed, enrichActivityWithAttachments, IPC_CONTRACT_VERSION, Hyperswarm,
   id, now, guildTopic
 } = require('../../../platform-class-imports')
+const { markRpcResponse } = require('../../../gossip-rpc-pull')
 
 
 /** Phase 756 — audit log & automation digest export */
@@ -482,15 +483,14 @@ async _fetchAutomationDigestSnapshotFromMeshOnce (snapshotId, opts = {}) {
     const rpcSnap = await this._tryFetchAutomationDigestSnapshotFromMeshRpc(snapshotId, opts)
     if (rpcSnap?.body?.length) {
       await this.deliveryReceipts.ingestAutomationDigestExportSnapshot(rpcSnap).catch(() => {})
-      return {
+      return markRpcResponse({
         snapshotId: rpcSnap.id || snapshotId,
         format: rpcSnap.format,
         body: rpcSnap.body,
         summaryLines: rpcSnap.summaryLines,
         exportedAt: rpcSnap.exportedAt,
-        fetchAttempt: (Number(opts.attempt) || 0) + 1,
-        viaRpc: true
-      }
+        fetchAttempt: (Number(opts.attempt) || 0) + 1
+      })
     }
   }
   const timeoutMs = Math.min(12000, Math.max(800, Number(opts.timeoutMs) || 3500))
@@ -593,11 +593,10 @@ async _fetchAuditExportArchiveFromMeshOnce (archiveId, opts = {}) {
     if (rpcArch?.entries?.length) {
       await this.deliveryReceipts.ingestAuditExportArchive(rpcArch).catch(() => {})
       const out = await this.exportAuditExportArchive(rpcArch.id || archiveId, opts)
-      return {
+      return markRpcResponse({
         ...out,
-        fetchAttempt: (Number(opts.attempt) || 0) + 1,
-        viaRpc: true
-      }
+        fetchAttempt: (Number(opts.attempt) || 0) + 1
+      })
     }
   }
   const timeoutMs = Math.min(12000, Math.max(800, Number(opts.timeoutMs) || 3500))

mixins/runtime/features/platform-automation-digest-snapshot-rpc-mixin.js

@@ -8,7 +8,9 @@ const {
   guildRpcTimeoutsMs,
   resolveGuildGossipRpcPeerIds,
   prepareGuildGossipRpcSession,
-  requestGuildGossipRpcFromPeers
+  requestGuildGossipRpcFromPeers,
+  pickFirstGuildRpcResponse,
+  isValidAutomationDigestSnapshotRpcResponse
 } = require('../../../gossip-rpc-pull')
 
 const platformAutomationDigestSnapshotRpcMixin = {
@@ -70,7 +72,7 @@ const platformAutomationDigestSnapshotRpcMixin = {
       rpcMs,
       wireMs
     })
-    const hit = responses.find((r) => r && typeof r.body === 'string' && r.body.length)
+    const hit = pickFirstGuildRpcResponse(responses, isValidAutomationDigestSnapshotRpcResponse)
     return hit || null
   }
 }

mixins/runtime/mesh/platform-mesh-view-mixin.js

@@ -5,7 +5,8 @@ const sharedScope = require('../../../platform-pearcord-shared-imports')
 const {
   guildRpcTimeoutsMs,
   resolveGuildGossipRpcHostPeerId,
-  prepareGuildGossipRpcSession
+  prepareGuildGossipRpcSession,
+  markRpcResponse
 } = require('../../../gossip-rpc-pull')
 
 const platformMeshViewMixin = {
@@ -37,13 +38,12 @@ const platformMeshViewMixin = {
     )
     if (!page?.guildId) return null
     const added = await this._ingestMemberPage(page)
-    return {
+    return markRpcResponse({
       requested: true,
-      viaRpc: true,
       offset: page.offset,
       memberCount: page.members?.length || 0,
       added
-    }
+    })
   },
 
   async _tryGuildSyncRequestRpc (channelId) {
@@ -79,12 +79,11 @@ const platformMeshViewMixin = {
     )
     if (!bundle?.guildId) return null
     await this._ingestGuildSync(bundle)
-    return {
+    return markRpcResponse({
       requested: true,
-      viaRpc: true,
       peerCount: 1,
       hostPublicKey: hostPk
-    }
+    })
   },
 
   _fanoutGuildSyncRequestBroadcast (channelId) {

mixins/runtime/view/platform-view-mixin.js

@@ -28,7 +28,7 @@ const {
   id, now, guildTopic
 } = require('../../../platform-class-imports')
 const { buildSettingsHubView } = require('pearcord-shared/settings-taxonomy')
-const { buildRpcWireViewSnapshot } = require('../../../gossip-rpc-pull')
+const { buildRpcWireViewSnapshot, buildGuildGossipRpcDiagnosticsSnapshot } = require('../../../gossip-rpc-pull')
 
 
 /** Phase 756 — IPC view snapshot */
@@ -2906,7 +2906,8 @@ async view (opts = {}) {
       : null,
     readReceiptSyncRows: await this._readReceiptSyncRowsForView(this.guild?.guild?.id),
     sparseAckSyncRows: this._sparseAckSyncRowsForView(this.guild?.guild?.id),
-    ...buildRpcWireViewSnapshot()
+    ...buildRpcWireViewSnapshot(),
+    ...buildGuildGossipRpcDiagnosticsSnapshot()
   }
 },