Merge branch '3.4.x'

Closes gh-46040

Author: philwebb

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/properties/bind/Binder.java

@@ -576,13 +576,15 @@ private <T> T withSource(ConfigurationPropertySource source, Supplier<T> supplie
 			if (source == null) {
 				return supplier.get();
 			}
+			ConfigurationPropertySource previous = this.source.get(0);
 			this.source.set(0, source);
 			this.sourcePushCount++;
 			try {
 				return supplier.get();
 			}
 			finally {
 				this.sourcePushCount--;
+				this.source.set(0, previous);
 			}
 		}
 

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/context/properties/bind/CollectionBinderTests.java

@@ -143,6 +143,21 @@ void bindToCollectionWhenNonKnownIndexedChildNotBoundThrowsException() {
 			});
 	}
 
+	@Test
+	void bindToNestedCollectionWhenNonKnownIndexed() {
+		// gh-46039
+		MockConfigurationPropertySource source = new MockConfigurationPropertySource();
+		source.put("foo[0].items[0]", "a");
+		source.put("foo[0].items[1]", "b");
+		source.put("foo[0].string", "test");
+		this.sources.add(source);
+		List<ExampleCollectionBean> list = this.binder.bind("foo", Bindable.listOf(ExampleCollectionBean.class)).get();
+		assertThat(list).hasSize(1);
+		ExampleCollectionBean bean = list.get(0);
+		assertThat(bean.getItems()).containsExactly("a", "b", "d");
+		assertThat(bean.getString()).isEqualTo("test");
+	}
+
 	@Test
 	void bindToNonScalarCollectionWhenNonSequentialShouldThrowException() {
 		MockConfigurationPropertySource source = new MockConfigurationPropertySource();
@@ -456,6 +471,8 @@ static class ExampleCollectionBean {
 
 		private Set<String> itemsSet = new LinkedHashSet<>();
 
+		private String string;
+
 		List<String> getItems() {
 			return this.items;
 		}
@@ -472,6 +489,14 @@ void setItemsSet(Set<String> itemsSet) {
 			this.itemsSet = itemsSet;
 		}
 
+		String getString() {
+			return this.string;
+		}
+
+		void setString(String string) {
+			this.string = string;
+		}
+
 	}
 
 	static class ExampleCustomNoDefaultConstructorBean {