List Editing Debug Logging

Overview

This document describes the debug logging added to diagnose the list item click-to-edit bug in rendered (WYSIWYG) mode. The bug causes clicking on list items to select the wrong content element.

Bug Symptoms

1. First list item: Clicking to edit selects the HEADER above instead of the list item
2. Other list items: Visual selection appears correct, but edits go to a DIFFERENT item (off-by-one or wrong index)

Enabling Debug Logging

Run Ferrite with the RUST_LOG environment variable set:

Windows (PowerShell)

$env:RUST_LOG="debug"; .\target\debug\ferrite.exe

Windows (CMD)

set RUST_LOG=debug && target\debug\ferrite.exe

Linux/macOS

RUST_LOG=debug ./target/debug/ferrite

Filter to Only List Debug Messages

RUST_LOG="ferrite::markdown::editor=debug" ./target/debug/ferrite

Debug Log Prefixes

All list-related debug messages are prefixed with [LIST_DEBUG] for easy filtering:

# Filter output with grep/findstr
RUST_LOG=debug ./target/debug/ferrite 2>&1 | grep "\[LIST_DEBUG\]"

Key Log Messages

Document Structure (Frame Start)

[LIST_DEBUG] ========== RENDERED EDITOR FRAME START ==========
[LIST_DEBUG] Document has N top-level nodes
[LIST_DEBUG] Root child [0]: type=Heading, lines=1..1, children=1
[LIST_DEBUG] Root child [1]: type=List, lines=3..6, children=3
[LIST_DEBUG]   List item [0]: lines=3..3, text_preview='First item'
[LIST_DEBUG]   List item [1]: lines=4..4, text_preview='Second item'

List Rendering

[LIST_DEBUG] render_list START: type=Bullet, indent=0, node_lines=3..6, child_count=3
[LIST_DEBUG] render_list: processing item child_idx=0, item_number=0, child_lines=3..3

List Item Rendering

[LIST_DEBUG] render_list_item START: item_number=0, node_lines=3..3, indent=0, child_count=1
[LIST_DEBUG] render_list_item: para_node found, para_lines=3..3, text_preview='First item'
[LIST_DEBUG] render_list_item: formatted_item_id uses node.start_line=3, has_inline_formatting=false

Click Detection

[LIST_DEBUG] CLICK DETECTED on list item: node.start_line=3, para.start_line=3, display_rect=..., item_number=0
[LIST_DEBUG] EDIT MODE ENTERED: formatted_item_id uses node.start_line=3, extracting from para.start_line=3, content='First item'

Content Extraction

[LIST_DEBUG] extract_list_item_content: start_line=3, raw_line='- First item', prefix='- ', content='First item'

Diagnosing the Bug

Symptom: Clicking first list item selects header

Look for mismatched line numbers:

[LIST_DEBUG] CLICK DETECTED on list item: node.start_line=1, ...  # Should be 3!

If node.start_line shows the header's line number instead of the list item's, the ID generation is using the wrong node.

Symptom: Off-by-one selection

Look for index vs item_number discrepancies:

[LIST_DEBUG] render_list: processing item child_idx=0, item_number=0, child_lines=3..3
[LIST_DEBUG] render_list: processing item child_idx=1, item_number=1, child_lines=4..4

If child_idx and the actual rendered position don't match, there may be an indexing bug.

Symptom: Wrong content extracted

Check the extraction log:

[LIST_DEBUG] extract_list_item_content: start_line=4, raw_line='- Second item', content='Second item'

If start_line doesn't match the clicked item, the line number mapping is incorrect.

Key Code Locations

Function	File	Purpose
render_list	src/markdown/editor.rs	Entry point for list rendering
render_list_item	src/markdown/editor.rs	Individual item rendering
render_list_with_structural_keys	src/markdown/editor.rs	Alternative rendering path
extract_list_item_content	src/markdown/editor.rs	Content extraction for editing
FormattedItemEditState	src/markdown/editor.rs	Edit state tracking

Test File

Use docs/test-list-editing-bug.md to reproduce the bug. It contains:

• A header immediately followed by a list (triggers the first-item bug)
• List items with formatting (tests inline formatting path)
• Nested lists (tests nested rendering)
• Numbered lists (tests ordered list rendering)

Fix Applied (Task 65)

The following issues were identified and fixed:

Root Cause

The formatted_item_id was created using node.start_line (the Item node), but content extraction used para.start_line (the Paragraph node). If these differed, the ID and content would not match, causing edits to go to the wrong item.

Fix Details

1. Moved ID creation inside the formatting block

   • Previously: formatted_item_id was created outside the has_inline_formatting block
   • Now: Created inside where para is available

2. Use para.start_line consistently

   • ID now uses para.start_line instead of node.start_line
   • This matches the line number used for content extraction

3. Added item_number/item_index to ID

   • Extra uniqueness guarantee: ui.id().with("formatted_list_item").with(para.start_line).with(item_number)
   • Prevents ID collision even if line numbers somehow match

4. Added explicit IDs to heading TextEdits

   • heading_widget_id = ui.id().with("heading_text").with(node.start_line)
   • Prevents any potential egui ID conflicts between headings and list items

Changed Files

• src/markdown/editor.rs:
  • render_list_item() - Fixed ID generation
  • render_list_item_with_structural_keys() - Fixed ID generation
  • render_heading() - Added explicit TextEdit ID
  • render_heading_with_structural_keys() - Added explicit TextEdit ID

Verification

After the fix, the debug logs should show:

[LIST_DEBUG] render_list_item FORMATTED: created ID with para.start_line=3, item_number=0, node.start_line=3

The para.start_line and the line used for content extraction should always match.