fix: archive old transcript files on /new and /reset (#14949)

Merged via /review-pr -> /prepare-pr -> /merge-pr.

Prepared head SHA: 4724df7dea
Co-authored-by: mcaxtr <7562095+mcaxtr@users.noreply.github.com>
Co-authored-by: gumadeiras <5599352+gumadeiras@users.noreply.github.com>
Reviewed-by: @gumadeiras

src/gateway/server-methods/sessions.ts

@@ -28,6 +28,7 @@ import {
 } from "../protocol/index.js";
 import {
   archiveFileOnDisk,
+  archiveSessionTranscripts,
   listSessionsFromStore,
   loadCombinedSessionStoreForGateway,
   loadSessionEntry,
@@ -68,6 +69,25 @@ function migrateAndPruneSessionStoreKey(params: {
   return { target, primaryKey, entry: params.store[primaryKey] };
 }
 
+function archiveSessionTranscriptsForSession(params: {
+  sessionId: string | undefined;
+  storePath: string;
+  sessionFile?: string;
+  agentId?: string;
+  reason: "reset" | "deleted";
+}): string[] {
+  if (!params.sessionId) {
+    return [];
+  }
+  return archiveSessionTranscripts({
+    sessionId: params.sessionId,
+    storePath: params.storePath,
+    sessionFile: params.sessionFile,
+    agentId: params.agentId,
+    reason: params.reason,
+  });
+}
+
 export const sessionsHandlers: GatewayRequestHandlers = {
   "sessions.list": ({ params, respond }) => {
     if (!validateSessionsListParams(params)) {
@@ -259,9 +279,13 @@ export const sessionsHandlers: GatewayRequestHandlers = {
     const cfg = loadConfig();
     const target = resolveGatewaySessionStoreTarget({ cfg, key });
     const storePath = target.storePath;
+    let oldSessionId: string | undefined;
+    let oldSessionFile: string | undefined;
     const next = await updateSessionStore(storePath, (store) => {
       const { primaryKey } = migrateAndPruneSessionStoreKey({ cfg, key, store });
       const entry = store[primaryKey];
+      oldSessionId = entry?.sessionId;
+      oldSessionFile = entry?.sessionFile;
       const now = Date.now();
       const nextEntry: SessionEntry = {
         sessionId: randomUUID(),
@@ -289,6 +313,14 @@ export const sessionsHandlers: GatewayRequestHandlers = {
       store[primaryKey] = nextEntry;
       return nextEntry;
     });
+    // Archive old transcript so it doesn't accumulate on disk (#14869).
+    archiveSessionTranscriptsForSession({
+      sessionId: oldSessionId,
+      storePath,
+      sessionFile: oldSessionFile,
+      agentId: target.agentId,
+      reason: "reset",
+    });
     respond(true, { ok: true, key: target.canonicalKey, entry: next }, undefined);
   },
   "sessions.delete": async ({ params, respond }) => {
@@ -357,24 +389,15 @@ export const sessionsHandlers: GatewayRequestHandlers = {
       }
     });
 
-    const archived: string[] = [];
-    if (deleteTranscript && sessionId) {
-      for (const candidate of resolveSessionTranscriptCandidates(
-        sessionId,
-        storePath,
-        entry?.sessionFile,
-        target.agentId,
-      )) {
-        if (!fs.existsSync(candidate)) {
-          continue;
-        }
-        try {
-          archived.push(archiveFileOnDisk(candidate, "deleted"));
-        } catch {
-          // Best-effort.
-        }
-      }
-    }
+    const archived = deleteTranscript
+      ? archiveSessionTranscriptsForSession({
+          sessionId,
+          storePath,
+          sessionFile: entry?.sessionFile,
+          agentId: target.agentId,
+          reason: "deleted",
+        })
+      : [];
 
     respond(true, { ok: true, key: target.canonicalKey, deleted: existed, archived }, undefined);
   },