Autosave only during code-mode

[kirangadhave]

Summary

• Tighten Transaction.source to Literal["frontend", "kernel", "code-mode", "file-watch"] so the closed set is type-checked.
• Rename code-mode's transaction emission from source="kernel" to source="code-mode", and gate _maybe_autosave on it.

Why

run_app_then_export_as_ipynb (and any other path using run_app_until_completion in EDIT mode) was rewriting source .py files as a side effect.

The fix flips the autosave default from "all kernel-sourced transactions persist" to "only code-mode transactions persist."

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated (UTC)
marimo-docs	Ready	Preview, Comment	May 4, 2026 9:55pm

[kirangadhave]

@cubic-dev-ai

[cubic-dev-ai]

@cubic-dev-ai

@kirangadhave I have started the AI code review. It will take a few minutes to complete.

[cubic-dev-ai]

No issues found across 4 files

Architecture diagram

sequenceDiagram
    participant CM as CodeModeContext
    participant K as Kernel
    participant L as NotificationListener
    participant S as Session
    participant FM as AppFileManager

    Note over CM, FM: Transaction Emission

    alt Code Editor Interaction
        CM->>CM: Generate document operations
        CM->>CM: NEW: Create Transaction(source="code-mode")
        CM->>S: notify(NotebookDocumentTransaction)
    else Kernel Bookkeeping
        K->>K: Internal state change (e.g. cell order)
        K->>K: CHANGED: Create Transaction(source="kernel")
        K->>S: notify(NotebookDocumentTransaction)
    end

    Note over S, L: Middleware / Extension Processing

    S->>L: _on_kernel_message(msg)
    L->>L: Deserialize Transaction
    L->>S: notify(applied_transaction)
    
    rect rgb(240, 240, 240)
        Note right of L: CHANGED: Persistence Gate (_maybe_autosave)
        L->>L: Check TransactionSource
        alt source == "code-mode"
            L->>FM: Save notebook to disk
            FM-->>L: Success/Failure
        else source == "kernel" OR "frontend" OR "file-watch"
            Note over L: Skip autosave to prevent<br/>unintended side effects
        end
    end

    opt Failure during Save
        L->>S: notify(AlertNotification)
    end

Loading

_{Partial review: This PR has more than 50 files, so cubic reviewed the highest-priority files first. During the trial, paid plans get a higher file limit.
You can try an ultrareview to bypass the file limit, comment @cubic-dev-ai ultrareview. Learn more.}

[kirangadhave]

removing bash-focus label which was auto-added

[github-actions]

🚀 Development release published. You may be able to view the changes at https://marimo.app?v=0.23.6-dev1