fix(ui): abort opening panel when no undos found

[y3owk1n]

Summary by CodeRabbit

• Bug Fixes

  • Added a warning message when there is no undo history available, preventing the undo tree UI from opening with empty data.

• Documentation

  • Updated the last change date in the documentation.

[coderabbitai]

Walkthrough

The changes consist of two updates: a documentation file had its last modified date updated, and the show_tree function in the UI module was enhanced with a guard clause. This clause checks if the undo tree is empty and, if so, notifies the user with a warning and exits early, preventing unnecessary UI setup when there is no undo history.

Changes

File(s)	Change Summary
doc/time-machine.nvim.txt	Updated the last change date in the file header comment from "2025 April 30" to "2025 May 04".
lua/time-machine/ui.lua	Added a guard clause to M.show_tree to notify the user and return early if no undo history exists.

Sequence Diagram(s)

sequenceDiagram
    participant User
    participant UI (show_tree)
    participant UndoTree

    User->>UI (show_tree): Request to show undo tree
    UI (show_tree)->>UndoTree: Build undo tree lines
    UndoTree-->>UI (show_tree): Return tree_lines
    alt tree_lines is empty
        UI (show_tree)->>User: Notify "No undos yet"
        UI (show_tree)-->User: Return early
    else tree_lines not empty
        UI (show_tree)->>User: Display undo tree UI
    end

Loading

Poem

A bunny hopped through time’s old tree,
But found no undos—none to see!
With gentle paws, it warned the crowd:
“No history here!” it squeaked aloud.
So onward now, with changes neat—
The code is safe, the loop’s complete.
🐇✨

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📜 Recent review details

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📥 Commits

Reviewing files that changed from the base of the PR and between c28178e and c16c250.

📒 Files selected for processing (2)

• doc/time-machine.nvim.txt (1 hunks)
• lua/time-machine/ui.lua (1 hunks)

🔇 Additional comments (2)

lua/time-machine/ui.lua (1)

392-395: Great improvement to UX - adding guard clause prevents empty UI creation

Adding this check to abort early when no undo history exists is a clean, effective solution that:

1. Prevents an empty UI panel from opening unnecessarily
2. Provides appropriate user feedback
3. Improves performance by avoiding UI setup when there's nothing to display

doc/time-machine.nvim.txt (1)

1-1: Updated documentation date correctly

Documentation date has been updated to reflect the recent code changes.

✨ Finishing Touches

• 📝 Generate Docstrings

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