Add try_* to add_slot_edge, add_node_edge (#6720)

# Objective

`add_node_edge` and `add_slot_edge` are fallible methods, but are always used with `.unwrap()`.
`input_node` is often unwrapped as well.
This points to having an infallible behaviour as default, with an alternative fallible variant if needed.

Improves readability and ergonomics.

## Solution

- Change `add_node_edge` and `add_slot_edge` to panic on error.
- Change `input_node` to panic on `None`.
- Add `try_add_node_edge` and `try_add_slot_edge` in case fallible methods are needed.
- Add `get_input_node` to still be able to get an `Option`.
---

## Changelog

### Added

- `try_add_node_edge`
- `try_add_slot_edge`
- `get_input_node`

### Changed

- `add_node_edge` is now infallible (panics on error)
- `add_slot_edge` is now infallible (panics on error)
- `input_node` now panics on `None`

## Migration Guide

Remove `.unwrap()` from `add_node_edge` and `add_slot_edge`.
For cases where the error was handled, use `try_add_node_edge` and `try_add_slot_edge` instead.

Remove `.unwrap()` from `input_node`.
For cases where the option was handled, use `get_input_node` instead.


Co-authored-by: Torstein Grindvik <52322338+torsteingrindvik@users.noreply.github.com>

Author: torsteingrindvik

crates/bevy_core_pipeline/src/bloom/mod.rs

@@ -59,27 +59,21 @@ impl Plugin for BloomPlugin {
                 .get_sub_graph_mut(crate::core_3d::graph::NAME)
                 .unwrap();
             draw_3d_graph.add_node(core_3d::graph::node::BLOOM, bloom_node);
-            draw_3d_graph
-                .add_slot_edge(
-                    draw_3d_graph.input_node().unwrap().id,
-                    crate::core_3d::graph::input::VIEW_ENTITY,
-                    core_3d::graph::node::BLOOM,
-                    BloomNode::IN_VIEW,
-                )
-                .unwrap();
+            draw_3d_graph.add_slot_edge(
+                draw_3d_graph.input_node().id,
+                crate::core_3d::graph::input::VIEW_ENTITY,
+                core_3d::graph::node::BLOOM,
+                BloomNode::IN_VIEW,
+            );
             // MAIN_PASS -> BLOOM -> TONEMAPPING
-            draw_3d_graph
-                .add_node_edge(
-                    crate::core_3d::graph::node::MAIN_PASS,
-                    core_3d::graph::node::BLOOM,
-                )
-                .unwrap();
-            draw_3d_graph
-                .add_node_edge(
-                    core_3d::graph::node::BLOOM,
-                    crate::core_3d::graph::node::TONEMAPPING,
-                )
-                .unwrap();
+            draw_3d_graph.add_node_edge(
+                crate::core_3d::graph::node::MAIN_PASS,
+                core_3d::graph::node::BLOOM,
+            );
+            draw_3d_graph.add_node_edge(
+                core_3d::graph::node::BLOOM,
+                crate::core_3d::graph::node::TONEMAPPING,
+            );
         }
 
         {
@@ -89,27 +83,21 @@ impl Plugin for BloomPlugin {
                 .get_sub_graph_mut(crate::core_2d::graph::NAME)
                 .unwrap();
             draw_2d_graph.add_node(core_2d::graph::node::BLOOM, bloom_node);
-            draw_2d_graph
-                .add_slot_edge(
-                    draw_2d_graph.input_node().unwrap().id,
-                    crate::core_2d::graph::input::VIEW_ENTITY,
-                    core_2d::graph::node::BLOOM,
-                    BloomNode::IN_VIEW,
-                )
-                .unwrap();
+            draw_2d_graph.add_slot_edge(
+                draw_2d_graph.input_node().id,
+                crate::core_2d::graph::input::VIEW_ENTITY,
+                core_2d::graph::node::BLOOM,
+                BloomNode::IN_VIEW,
+            );
             // MAIN_PASS -> BLOOM -> TONEMAPPING
-            draw_2d_graph
-                .add_node_edge(
-                    crate::core_2d::graph::node::MAIN_PASS,
-                    core_2d::graph::node::BLOOM,
-                )
-                .unwrap();
-            draw_2d_graph
-                .add_node_edge(
-                    core_2d::graph::node::BLOOM,
-                    crate::core_2d::graph::node::TONEMAPPING,
-                )
-                .unwrap();
+            draw_2d_graph.add_node_edge(
+                crate::core_2d::graph::node::MAIN_PASS,
+                core_2d::graph::node::BLOOM,
+            );
+            draw_2d_graph.add_node_edge(
+                core_2d::graph::node::BLOOM,
+                crate::core_2d::graph::node::TONEMAPPING,
+            );
         }
     }
 }

crates/bevy_core_pipeline/src/core_2d/mod.rs

@@ -72,45 +72,33 @@ impl Plugin for Core2dPlugin {
             graph::input::VIEW_ENTITY,
             SlotType::Entity,
         )]);
-        draw_2d_graph
-            .add_slot_edge(
-                input_node_id,
-                graph::input::VIEW_ENTITY,
-                graph::node::MAIN_PASS,
-                MainPass2dNode::IN_VIEW,
-            )
-            .unwrap();
-        draw_2d_graph
-            .add_slot_edge(
-                input_node_id,
-                graph::input::VIEW_ENTITY,
-                graph::node::TONEMAPPING,
-                TonemappingNode::IN_VIEW,
-            )
-            .unwrap();
-        draw_2d_graph
-            .add_slot_edge(
-                input_node_id,
-                graph::input::VIEW_ENTITY,
-                graph::node::UPSCALING,
-                UpscalingNode::IN_VIEW,
-            )
-            .unwrap();
-        draw_2d_graph
-            .add_node_edge(graph::node::MAIN_PASS, graph::node::TONEMAPPING)
-            .unwrap();
-        draw_2d_graph
-            .add_node_edge(
-                graph::node::TONEMAPPING,
-                graph::node::END_MAIN_PASS_POST_PROCESSING,
-            )
-            .unwrap();
-        draw_2d_graph
-            .add_node_edge(
-                graph::node::END_MAIN_PASS_POST_PROCESSING,
-                graph::node::UPSCALING,
-            )
-            .unwrap();
+        draw_2d_graph.add_slot_edge(
+            input_node_id,
+            graph::input::VIEW_ENTITY,
+            graph::node::MAIN_PASS,
+            MainPass2dNode::IN_VIEW,
+        );
+        draw_2d_graph.add_slot_edge(
+            input_node_id,
+            graph::input::VIEW_ENTITY,
+            graph::node::TONEMAPPING,
+            TonemappingNode::IN_VIEW,
+        );
+        draw_2d_graph.add_slot_edge(
+            input_node_id,
+            graph::input::VIEW_ENTITY,
+            graph::node::UPSCALING,
+            UpscalingNode::IN_VIEW,
+        );
+        draw_2d_graph.add_node_edge(graph::node::MAIN_PASS, graph::node::TONEMAPPING);
+        draw_2d_graph.add_node_edge(
+            graph::node::TONEMAPPING,
+            graph::node::END_MAIN_PASS_POST_PROCESSING,
+        );
+        draw_2d_graph.add_node_edge(
+            graph::node::END_MAIN_PASS_POST_PROCESSING,
+            graph::node::UPSCALING,
+        );
         graph.add_sub_graph(graph::NAME, draw_2d_graph);
     }
 }

crates/bevy_core_pipeline/src/core_3d/mod.rs

@@ -82,45 +82,33 @@ impl Plugin for Core3dPlugin {
             graph::input::VIEW_ENTITY,
             SlotType::Entity,
         )]);
-        draw_3d_graph
-            .add_slot_edge(
-                input_node_id,
-                graph::input::VIEW_ENTITY,
-                graph::node::MAIN_PASS,
-                MainPass3dNode::IN_VIEW,
-            )
-            .unwrap();
-        draw_3d_graph
-            .add_slot_edge(
-                input_node_id,
-                graph::input::VIEW_ENTITY,
-                graph::node::TONEMAPPING,
-                TonemappingNode::IN_VIEW,
-            )
-            .unwrap();
-        draw_3d_graph
-            .add_slot_edge(
-                input_node_id,
-                graph::input::VIEW_ENTITY,
-                graph::node::UPSCALING,
-                UpscalingNode::IN_VIEW,
-            )
-            .unwrap();
-        draw_3d_graph
-            .add_node_edge(graph::node::MAIN_PASS, graph::node::TONEMAPPING)
-            .unwrap();
-        draw_3d_graph
-            .add_node_edge(
-                graph::node::TONEMAPPING,
-                graph::node::END_MAIN_PASS_POST_PROCESSING,
-            )
-            .unwrap();
-        draw_3d_graph
-            .add_node_edge(
-                graph::node::END_MAIN_PASS_POST_PROCESSING,
-                graph::node::UPSCALING,
-            )
-            .unwrap();
+        draw_3d_graph.add_slot_edge(
+            input_node_id,
+            graph::input::VIEW_ENTITY,
+            graph::node::MAIN_PASS,
+            MainPass3dNode::IN_VIEW,
+        );
+        draw_3d_graph.add_slot_edge(
+            input_node_id,
+            graph::input::VIEW_ENTITY,
+            graph::node::TONEMAPPING,
+            TonemappingNode::IN_VIEW,
+        );
+        draw_3d_graph.add_slot_edge(
+            input_node_id,
+            graph::input::VIEW_ENTITY,
+            graph::node::UPSCALING,
+            UpscalingNode::IN_VIEW,
+        );
+        draw_3d_graph.add_node_edge(graph::node::MAIN_PASS, graph::node::TONEMAPPING);
+        draw_3d_graph.add_node_edge(
+            graph::node::TONEMAPPING,
+            graph::node::END_MAIN_PASS_POST_PROCESSING,
+        );
+        draw_3d_graph.add_node_edge(
+            graph::node::END_MAIN_PASS_POST_PROCESSING,
+            graph::node::UPSCALING,
+        );
         graph.add_sub_graph(graph::NAME, draw_3d_graph);
     }
 }

crates/bevy_core_pipeline/src/fxaa/mod.rs

@@ -103,27 +103,21 @@ impl Plugin for FxaaPlugin {
 
             graph.add_node(core_3d::graph::node::FXAA, fxaa_node);
 
-            graph
-                .add_slot_edge(
-                    graph.input_node().unwrap().id,
-                    core_3d::graph::input::VIEW_ENTITY,
-                    core_3d::graph::node::FXAA,
-                    FxaaNode::IN_VIEW,
-                )
-                .unwrap();
-
-            graph
-                .add_node_edge(
-                    core_3d::graph::node::TONEMAPPING,
-                    core_3d::graph::node::FXAA,
-                )
-                .unwrap();
-            graph
-                .add_node_edge(
-                    core_3d::graph::node::FXAA,
-                    core_3d::graph::node::END_MAIN_PASS_POST_PROCESSING,
-                )
-                .unwrap();
+            graph.add_slot_edge(
+                graph.input_node().id,
+                core_3d::graph::input::VIEW_ENTITY,
+                core_3d::graph::node::FXAA,
+                FxaaNode::IN_VIEW,
+            );
+
+            graph.add_node_edge(
+                core_3d::graph::node::TONEMAPPING,
+                core_3d::graph::node::FXAA,
+            );
+            graph.add_node_edge(
+                core_3d::graph::node::FXAA,
+                core_3d::graph::node::END_MAIN_PASS_POST_PROCESSING,
+            );
         }
         {
             let fxaa_node = FxaaNode::new(&mut render_app.world);
@@ -132,27 +126,21 @@ impl Plugin for FxaaPlugin {
 
             graph.add_node(core_2d::graph::node::FXAA, fxaa_node);
 
-            graph
-                .add_slot_edge(
-                    graph.input_node().unwrap().id,
-                    core_2d::graph::input::VIEW_ENTITY,
-                    core_2d::graph::node::FXAA,
-                    FxaaNode::IN_VIEW,
-                )
-                .unwrap();
-
-            graph
-                .add_node_edge(
-                    core_2d::graph::node::TONEMAPPING,
-                    core_2d::graph::node::FXAA,
-                )
-                .unwrap();
-            graph
-                .add_node_edge(
-                    core_2d::graph::node::FXAA,
-                    core_2d::graph::node::END_MAIN_PASS_POST_PROCESSING,
-                )
-                .unwrap();
+            graph.add_slot_edge(
+                graph.input_node().id,
+                core_2d::graph::input::VIEW_ENTITY,
+                core_2d::graph::node::FXAA,
+                FxaaNode::IN_VIEW,
+            );
+
+            graph.add_node_edge(
+                core_2d::graph::node::TONEMAPPING,
+                core_2d::graph::node::FXAA,
+            );
+            graph.add_node_edge(
+                core_2d::graph::node::FXAA,
+                core_2d::graph::node::END_MAIN_PASS_POST_PROCESSING,
+            );
         }
     }
 }

crates/bevy_pbr/src/lib.rs

@@ -256,19 +256,15 @@ impl Plugin for PbrPlugin {
             .get_sub_graph_mut(bevy_core_pipeline::core_3d::graph::NAME)
             .unwrap();
         draw_3d_graph.add_node(draw_3d_graph::node::SHADOW_PASS, shadow_pass_node);
-        draw_3d_graph
-            .add_node_edge(
-                draw_3d_graph::node::SHADOW_PASS,
-                bevy_core_pipeline::core_3d::graph::node::MAIN_PASS,
-            )
-            .unwrap();
-        draw_3d_graph
-            .add_slot_edge(
-                draw_3d_graph.input_node().unwrap().id,
-                bevy_core_pipeline::core_3d::graph::input::VIEW_ENTITY,
-                draw_3d_graph::node::SHADOW_PASS,
-                ShadowPassNode::IN_VIEW,
-            )
-            .unwrap();
+        draw_3d_graph.add_node_edge(
+            draw_3d_graph::node::SHADOW_PASS,
+            bevy_core_pipeline::core_3d::graph::node::MAIN_PASS,
+        );
+        draw_3d_graph.add_slot_edge(
+            draw_3d_graph.input_node().id,
+            bevy_core_pipeline::core_3d::graph::input::VIEW_ENTITY,
+            draw_3d_graph::node::SHADOW_PASS,
+            ShadowPassNode::IN_VIEW,
+        );
     }
 }

crates/bevy_render/src/render_graph/context.rs

@@ -169,7 +169,7 @@ impl<'a> RenderGraphContext<'a> {
             .graph
             .get_sub_graph(&name)
             .ok_or_else(|| RunSubGraphError::MissingSubGraph(name.clone()))?;
-        if let Some(input_node) = sub_graph.input_node() {
+        if let Some(input_node) = sub_graph.get_input_node() {
             for (i, input_slot) in input_node.input_slots.iter().enumerate() {
                 if let Some(input_value) = inputs.get(i) {
                     if input_slot.slot_type != input_value.slot_type() {