| name | perf-hotpath-guard |
| description | INTERNAL DEV WORKFLOW for WpfHexEditor — Claude self-invokes after editing
C# in render/layout/scroll hot paths (HexEditor/, CodeEditor/Rendering*,
*Viewport*, *GlyphRun*, *Renderer*, *ScrollHandler*, OnRender,
MeasureOverride, ArrangeOverride) to detect allocations and patterns that
cause jank or GC pressure. Skip on: tests, mocks, designer files, non-render
code in non-hot directories.
|
perf-hotpath-guard (internal)
Catches perf anti-patterns from project history (jank, GC pressure in render loops). Memory anchors: adr_006_zoom_rendering, adr_hexeditor_viewport_race, bug_drag_scroll_fix, feedback_wordwrap_column, bug_doc_editor_caret_hittest.
When I invoke
Trigger: .cs edits matching ANY of:
- Path under
HexEditor/ or CodeEditor/Rendering
- Filename contains
Viewport, GlyphRun, Renderer, ScrollHandler
- Edit modifies
OnRender, MeasureOverride, or ArrangeOverride
Skip if path contains Test, Mock, *.Designer.cs, *.g.cs, *.g.i.cs.
Pipeline
scripts/hotpath-scan.ps1 -Files <paths> (applies rules inside hot-method bodies only) → HotPath: <n> issues or OK.
9 rules
See references/perf-rules.md for regex + rationale.
| Rule | Anchor |
|---|
alloc-in-render | GC pressure/jank |
linq-in-hot | allocations + delegate creation |
string-concat-loop | O(n²) allocations |
boxing | struct→object passing |
dispatcher-cosmetic | feedback_wordwrap_column anti-pattern |
formatted-text-recreate | bug_doc_editor_caret_hittest |
glyph-run-recreate | render cost without pool |
findvisualchild-render | O(n) tree walk every frame |
regex-in-render | compile cost on hot path |
Hot methods (from references/hot-methods.md): OnRender, MeasureOverride, ArrangeOverride, OnPreviewMouseMove, OnScrollChanged, Render*/Draw*/Paint* in renderer files, any method preceded by // HOT. Exclude with // COLD.
Output
HotPath: 2 issues
HexLineRenderer.cs:142 alloc-in-render OnRender -> new SolidColorBrush(...)
TextViewport.cs:88 formatted-text-recreate OnRender -> new FormattedText(...)
Suppress: // alloc-ok: <reason> (alloc-in-render), // COLD (exclude method), // HOT-EXCEPTION: <note> (document legitimate exception).
Static analysis only — no runtime profiling, no code rewrite.
