Method beginEditSession

src/durable-objects/user-notes.ts:329–339

(noteId: string)

        // Identical to head → nothing to record
        if (head?.content_hash && head.content_hash === hash) return null;

        // Defense-in-depth: never record an accidental wipe as a version. A
        // transient empty doc (load race, reconnect, stale beacon) snapshotted
        // over real content is what corrupts history into "deleted everything"
        // diffs. If the new content is blank but the previous version had text,
        // skip — the client-side guard should already prevent this, but old
        // clients and the unmount beacon can still slip an empty doc through.
        // Fail closed: if we can't read the previous version (R2 blip), don't
        // record the empty doc either.
        if (head && isEmptyDoc(content)) {
            let prevContent: string;
            try {
                prevContent = await this.reconstructVersion(head.id, noteId, { strict: true });
            } catch {