Complexity Growth Tracker — Warn when functions increase in complexity over time

[NK2552003]

Developers only see current cyclomatic complexity. There's no visibility into how complexity evolves across commits, leading to gradual debt accumulation.

Objective

Track function-level complexity trends over Git history and warn when growth exceeds configurable thresholds.

Scope & Implementation Details

1. Complexity Calculation

• Parse file AST using @typescript-eslint/typescript-estree or tree-sitter
• Compute Cyclomatic Complexity (CC) per function/method
• Store: { name, range, cc, filePath }

2. Git Comparison

• Fetch historical snapshots: git log --follow -p -- <file>
• Extract function CC at each commit
• Compare current CC vs 5/10/30-day averages

3. Warning System

• Inline decoration on function name if growth > threshold (default: 50%)
• Status bar notification: "⚠️ Function complexity grew +85% in 14 days"
• Hover tooltip shows trend chart (text-based or simple markdown table)

4. Configuration

• complexityTracker.thresholdPercent (default: 50)
• complexityTracker.lookbackDays (default: 14)
• complexityTracker.ignoredFunctions (string[])

Acceptance Criteria

• Computes CC accurately for TS/JS functions
• Compares against historical Git states
• Triggers warning when growth exceeds threshold
• Shows inline decoration + hover details
• Runs asynchronously without blocking saves

Technical Notes

• Use git show <commit>:<file> to parse historical ASTs
• Cache AST parses to avoid re-running on unchanged files
• Limit history depth to last 20 commits to prevent slowdowns
• Handle syntax errors gracefully (skip malformed files)

[sidkr222003]

I would like to work on this issue.