发布

  • fix(core): prevent TUI buffer overflow panics in dependency view scrollbar rendering (#32292)

    frostbyte_neo 发布于 2025-08-11 20:08:09 +00:00

    Current Behavior

    The TUI dependency view experiences buffer overflow panics when
    rendering scrollbars on small or constrained terminal sizes. Users
    encounter crashes with messages like "index outside of buffer" at
    various coordinates such as (134, 37), (86, 0), (107, 0), etc.

    Expected Behavior

    The TUI should handle all terminal sizes gracefully without crashing,
    maintaining proper visual rendering of scrollbars and padding elements
    while staying within buffer boundaries.

    Key Code Changes

    The fix adds clean, reusable helper functions for bounds checking to
    prevent buffer overflows:

    1. New Helper Functions (lines 216-239):

    /// Check if a rectangle fits within buffer boundaries
    fn fits_in_buffer(area: &Rect, buf: &Buffer) -> bool {
        area.x + area.width <= buf.area().width && area.y < buf.area().height
    }
    
    /// Create a safe rectangle clamped to buffer boundaries
    fn clamp_to_buffer(area: Rect, buf: &Buffer) -> Option<Rect> {
        if area.width == 0 || area.height == 0 {
            return None;
        }
        let safe_area = Rect {
            x: area.x,
            y: area.y,
            width: area.width.min(buf.area().width.saturating_sub(area.x)),
            height: area.height.min(buf.area().height.saturating_sub(area.y)),
        };
        if safe_area.width > 0 && safe_area.height > 0 { Some(safe_area) } else { None }
    }
    

    2. Simplified Scrollbar Bounds Check (lines 478-481):

    // Render scrollbar with bounds checking
    if let Some(safe_scrollbar_area) = Self::clamp_to_buffer(outer_area, buf) {
        scrollbar.render(safe_scrollbar_area, buf, &mut state.scrollbar_state);
    }
    

    3. Cleaner Padding Validation (lines 241-286):

    fn render_scrollbar_padding(outer_area: Rect, buf: &mut Buffer, style: Style) {
        const PADDING_WIDTH: u16 = 2;
        const RIGHT_MARGIN: u16 = 3;
        const WIDTH_PADDING: u16 = 2;
        const TOTAL_WIDTH: u16 = PADDING_WIDTH + RIGHT_MARGIN + WIDTH_PADDING;
    
        // Early exit if area is too small or has no height
        if outer_area.width < TOTAL_WIDTH || outer_area.height == 0 {
            return;
        }
        
        // Use helper function for bounds checking
        if Self::fits_in_buffer(&top_area, buf) {
            // render top padding
        }
        if Self::fits_in_buffer(&bottom_area, buf) {
            // render bottom padding  
        }
    }
    

    Key improvements:

    • Reduced complexity: Scrollbar bounds checking went from 11 lines
      to 3 lines
    • Reusable helpers: fits_in_buffer() and clamp_to_buffer() can
      be used throughout the codebase
    • Named constants: Replaced magic numbers with descriptive constants
    • Clear intent: Function names clearly express what the code does

    Related Issue(s)

    This fixes buffer overflow panics that occur when the terminal user
    interface attempts to render scrollbar widgets and padding outside the
    available buffer boundaries, particularly on smaller terminal sizes or
    when the terminal is resized.

    The fix adds minimal bounds checking to:

    1. Scrollbar rendering: Validates the scrollbar area fits within
      buffer boundaries before rendering
    2. Padding rendering: Ensures top/bottom padding areas don't extend
      beyond buffer limits

    Comprehensive test coverage added: 10 unit tests covering all edge
    cases including the specific problematic buffer dimensions that
    previously caused panics (45×30, 76×30, 104×30, 135×37, etc.).

    Tested across multiple terminal buffer sizes and confirmed no more
    buffer overflow panics while maintaining correct scrollbar
    functionality.

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