fix(agent-core): allow benign session rewrites with different inode

Hermes · Hermes · commit 7e6995d0fbd5 · 2026-05-31T22:10:56.000+08:00
Compaction rewrites session files via writeFile+rename, which always
creates a new inode. Previously, sessionFenceRewriteIsBenign rejected
such rewrites at the identity check (sameSessionFileIdentity), so the
content validation that follows never ran, causing
EmbeddedAttemptSessionTakeoverError false positives.

This change removes the inode identity gate from sessionFenceRewriteIsBenign
while preserving all content validation: file must exist, end with a
newline, append only valid transcript lines. A file with a different inode
but valid compaction-style content is indistinguishable from a compaction
from the agent's perspective, so the inode check was both too strict and
redundant with the content checks.

Fixes EmbeddedAttemptSessionTakeoverError during concurrent compaction.
diff --git a/src/agents/embedded-agent-runner/run/attempt.session-lock.ts b/src/agents/embedded-agent-runner/run/attempt.session-lock.ts
@@ -263,7 +263,6 @@ async function sessionFenceRewriteIsBenign(params: {
     !params.previous?.fingerprint.exists ||
     !params.current.exists ||
     !params.previous.text ||
-    !sameSessionFileIdentity(params.previous.fingerprint, params.current) ||
     params.current.size > BigInt(MAX_BENIGN_SESSION_FENCE_REWRITE_RESULT_BYTES) ||
     params.current.size > MAX_SAFE_FILE_OFFSET
   ) {
