Extract stroke commit input binding helper

docs/modernization/debt.md

@@ -105,6 +105,9 @@ agent or engineer to remove them without reconstructing context from chat.
 - 2026-06-13: `DEBT-0036` was narrowed again. `Canvas::stroke_commit()`
   now keeps the commit callback bundle in a local helper, leaving the callsite
   with sequence planning and retained callback invocation only.
+- 2026-06-13: `DEBT-0036` was narrowed again. `Canvas::stroke_commit()`
+  now routes the commit-input texture role switch through a local helper,
+  leaving the callsite with sequence planning plus retained callback wiring.
 - 2026-06-13: `DEBT-0036` was narrowed again. `NodeStrokePreview::draw_stroke_immediate()`
   now routes final composite execution and preview copy-back through a retained
   local wrapper, leaving the call site with only sequence wiring.

docs/modernization/tasks.md

@@ -650,6 +650,9 @@ Progress Notes:
 - 2026-06-13: `Canvas::stroke_commit()` now keeps the commit callback bundle
   in a local helper, leaving the callsite with sequence planning and retained
   callback invocation only.
+- 2026-06-13: `Canvas::stroke_commit()` now routes the commit-input texture
+  role switch through a local helper, so the callsite no longer owns that
+  inline texture binding bundle.
 - 2026-06-13: `Canvas::stroke_draw_samples()` now reuses a retained destination
   texture dispatch helper for the live sample path; `Canvas` still owns the
   concrete face textures and callback execution.

src/canvas.cpp

@@ -542,6 +542,49 @@ static auto make_canvas_stroke_commit_callbacks(
     const pp::paint_renderer::CanvasStrokeCommitMaterialPlan& stroke_material)
 {
     const auto& b = current_stroke->m_brush;
+    auto bind_commit_inputs = [&](int i) {
+        pp::panopainter::bind_legacy_canvas_stroke_commit_inputs(
+            sequence,
+            [&](int texture_slot) {
+                set_active_texture_unit(texture_slot);
+            },
+            [&](pp::paint_renderer::CanvasStrokeCommitTextureRole role) {
+                switch (role) {
+                case pp::paint_renderer::CanvasStrokeCommitTextureRole::layer_scratch:
+                    canvas.m_tex2[i].bind();
+                    break;
+                case pp::paint_renderer::CanvasStrokeCommitTextureRole::stroke:
+                    canvas.m_tmp[i].bindTexture();
+                    break;
+                case pp::paint_renderer::CanvasStrokeCommitTextureRole::selection_mask:
+                    canvas.m_smask.rtt(i).bindTexture();
+                    break;
+                case pp::paint_renderer::CanvasStrokeCommitTextureRole::dual_stroke:
+                    canvas.m_tmp_dual[i].bindTexture();
+                    break;
+                case pp::paint_renderer::CanvasStrokeCommitTextureRole::pattern:
+                    b->m_pattern_texture ? b->m_pattern_texture->bind() : unbind_texture_2d();
+                    break;
+                }
+            },
+            [&](pp::paint_renderer::CanvasStrokeCommitTextureRole role, int texture_slot) {
+                switch (role) {
+                case pp::paint_renderer::CanvasStrokeCommitTextureRole::layer_scratch:
+                    canvas.m_sampler.bind(texture_slot);
+                    break;
+                case pp::paint_renderer::CanvasStrokeCommitTextureRole::stroke:
+                    canvas.m_sampler_nearest.bind(texture_slot);
+                    break;
+                case pp::paint_renderer::CanvasStrokeCommitTextureRole::selection_mask:
+                case pp::paint_renderer::CanvasStrokeCommitTextureRole::dual_stroke:
+                    canvas.m_sampler.bind(texture_slot);
+                    break;
+                case pp::paint_renderer::CanvasStrokeCommitTextureRole::pattern:
+                    canvas.m_sampler_stencil.bind(texture_slot);
+                    break;
+                }
+            });
+    };
     return pp::panopainter::make_legacy_canvas_stroke_commit_callbacks(
         [&]() {
             canvas.m_dirty = false;
@@ -604,47 +647,7 @@ static auto make_canvas_stroke_commit_callbacks(
             canvas.m_tex2[i].unbind();
         },
         [&](int i) {
-            pp::panopainter::bind_legacy_canvas_stroke_commit_inputs(
+            bind_commit_inputs(i);
-                sequence,
-                [&](int texture_slot) {
-                    set_active_texture_unit(texture_slot);
-                },
-                [&](pp::paint_renderer::CanvasStrokeCommitTextureRole role) {
-                    switch (role) {
-                    case pp::paint_renderer::CanvasStrokeCommitTextureRole::layer_scratch:
-                        canvas.m_tex2[i].bind();
-                        break;
-                    case pp::paint_renderer::CanvasStrokeCommitTextureRole::stroke:
-                        canvas.m_tmp[i].bindTexture();
-                        break;
-                    case pp::paint_renderer::CanvasStrokeCommitTextureRole::selection_mask:
-                        canvas.m_smask.rtt(i).bindTexture();
-                        break;
-                    case pp::paint_renderer::CanvasStrokeCommitTextureRole::dual_stroke:
-                        canvas.m_tmp_dual[i].bindTexture();
-                        break;
-                    case pp::paint_renderer::CanvasStrokeCommitTextureRole::pattern:
-                        b->m_pattern_texture ? b->m_pattern_texture->bind() : unbind_texture_2d();
-                        break;
-                    }
-                },
-                [&](pp::paint_renderer::CanvasStrokeCommitTextureRole role, int texture_slot) {
-                    switch (role) {
-                    case pp::paint_renderer::CanvasStrokeCommitTextureRole::layer_scratch:
-                        canvas.m_sampler.bind(texture_slot);
-                        break;
-                    case pp::paint_renderer::CanvasStrokeCommitTextureRole::stroke:
-                        canvas.m_sampler_nearest.bind(texture_slot);
-                        break;
-                    case pp::paint_renderer::CanvasStrokeCommitTextureRole::selection_mask:
-                    case pp::paint_renderer::CanvasStrokeCommitTextureRole::dual_stroke:
-                        canvas.m_sampler.bind(texture_slot);
-                        break;
-                    case pp::paint_renderer::CanvasStrokeCommitTextureRole::pattern:
-                        canvas.m_sampler_stencil.bind(texture_slot);
-                        break;
-                    }
-                });
         },
         [&](int) {
             pp::panopainter::execute_legacy_canvas_stroke_commit_erase(