From e392e99f7e12e8c69f7b6da57bcc341f26a70841 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=D0=A1=D0=B0=D0=BD=D1=8F=20=D0=A7=D0=B5=D1=80=D0=B5=D0=BF?=
 <sdesya74@gmail.com>
Date: Wed, 15 Feb 2023 22:56:22 +0000
Subject: [PATCH] feat: improve `initialize_bundle` error message (#7464)
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# Objective

This PR improves message that caused by duplicate components in bundle.

## Solution

Show names of duplicate components.

The solution is not very elegant, in my opinion, I will be happy to listen to suggestions for improving it

Co-authored-by: Саня Череп <41489405+SDesya74@users.noreply.github.com>
---
 crates/bevy_ecs/src/bundle.rs | 30 +++++++++++++++++++++++++-----
 1 file changed, 25 insertions(+), 5 deletions(-)

diff --git a/crates/bevy_ecs/src/bundle.rs b/crates/bevy_ecs/src/bundle.rs
index 34d9b428ca..a2d091e549 100644
--- a/crates/bevy_ecs/src/bundle.rs
+++ b/crates/bevy_ecs/src/bundle.rs
@@ -3,6 +3,7 @@
 //! This module contains the [`Bundle`] trait and some other helper types.
 
 pub use bevy_ecs_macros::Bundle;
+use bevy_utils::HashSet;
 
 use crate::{
     archetype::{
@@ -710,7 +711,7 @@ impl Bundles {
             let id = BundleId(bundle_infos.len());
             let bundle_info =
                 // SAFETY: T::component_id ensures info was created
-                unsafe { initialize_bundle(std::any::type_name::<T>(), component_ids, id) };
+                unsafe { initialize_bundle(std::any::type_name::<T>(), components, component_ids, id) };
             bundle_infos.push(bundle_info);
             id
         });
@@ -724,16 +725,35 @@ impl Bundles {
 /// `component_id` must be valid [`ComponentId`]'s
 unsafe fn initialize_bundle(
     bundle_type_name: &'static str,
+    components: &Components,
     component_ids: Vec<ComponentId>,
     id: BundleId,
 ) -> BundleInfo {
     let mut deduped = component_ids.clone();
     deduped.sort();
     deduped.dedup();
-    assert!(
-        deduped.len() == component_ids.len(),
-        "Bundle {bundle_type_name} has duplicate components",
-    );
+
+    if deduped.len() != component_ids.len() {
+        // TODO: Replace with `Vec::partition_dedup` once https://github.com/rust-lang/rust/issues/54279 is stabilized
+        let mut seen = HashSet::new();
+        let mut dups = Vec::new();
+        for id in component_ids {
+            if !seen.insert(id) {
+                dups.push(id);
+            }
+        }
+
+        let names = dups
+            .into_iter()
+            .map(|id| {
+                // SAFETY: component_id exists and is therefore valid
+                unsafe { components.get_info_unchecked(id).name() }
+            })
+            .collect::<Vec<_>>()
+            .join(", ");
+
+        panic!("Bundle {bundle_type_name} has duplicate components: {names}");
+    }
 
     BundleInfo { id, component_ids }
 }