fix(sandbox): unblock multi-sandbox when host pyzmq lags PyPI

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This pull request was authored by a coding agent.

📝 Summary

Opening a notebook from marimo edit --sandbox (directory or home page) can fail to build the kernel venv:

Because you require pyzmq{...}==27.2.0 and pyzmq==27.1.0,
we can conclude that your requirements are unsatisfiable.

The editor pinned its installed pyzmq into the sandbox so host and kernel would match. uv export independently locks marimo's transitive pyzmq from PyPI. Those versions diverge whenever the host was installed before a new pyzmq release — here 27.1.0 in the repo lock vs 27.2.0 on PyPI. The notebook never asked for pyzmq.

We stopped exact-pinning. IPC only needs pyzmq>=27.1.0; ZMQ does not require the same wheel on both sides. If the lock already has pyzmq, we skip adding a second line. That avoids a merge engine for a conflict we were creating ourselves.

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Written by cursor-grok-4.6 on Cursor

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[cubic-dev-ai]

1 issue found across 4 files

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Prompt for AI agents (unresolved issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="marimo/_cli/sandbox.py">

<violation number="1" location="marimo/_cli/sandbox.py:583">
P1: When a notebook’s existing `pyzmq` line has a false environment marker, this name-only check suppresses the unconditional IPC dependency, leaving the kernel venv without `pyzmq`. Evaluate PEP 508 markers before treating an existing line as satisfying `get_ipc_kernel_deps()`.</violation>
</file>

<sub>Reply with feedback, questions, or to request a fix.

Re-trigger cubic</sub>

[cubic-dev-ai]

P1: When a notebook’s existing pyzmq line has a false environment marker, this name-only check suppresses the unconditional IPC dependency, leaving the kernel venv without pyzmq. Evaluate PEP 508 markers before treating an existing line as satisfying get_ipc_kernel_deps().

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. At marimo/_cli/sandbox.py, line 583:

<comment>When a notebook’s existing `pyzmq` line has a false environment marker, this name-only check suppresses the unconditional IPC dependency, leaving the kernel venv without `pyzmq`. Evaluate PEP 508 markers before treating an existing line as satisfying `get_ipc_kernel_deps()`.</comment>

<file context>
@@ -570,15 +579,14 @@ def get_sandbox_requirements(
-            d.lower().split("[")[0].split(">=")[0].split("==")[0]
-            for d in normalized
-        }
+        existing = {_requirement_name(dep) for dep in normalized}
+        existing.discard("")
         for dep in additional_deps:
</file context>