fix: breadcrumbs for hidden category can not be displayed (#6200)

#### What type of PR is this?
/kind bug
/area core
/area theme
/milestone 2.17.x

#### What this PR does / why we need it:
修复获取隐藏分类的面包屑路径不正确的问题

#### Which issue(s) this PR fixes:
Fixes #6197

#### Does this PR introduce a user-facing change?
```release-note
修复获取隐藏分类的面包屑路径不正确的问题
```

application/src/main/java/run/halo/app/theme/finders/impl/CategoryFinderImpl.java

@@ -17,6 +17,7 @@ import org.apache.commons.lang3.BooleanUtils;
 import org.apache.commons.lang3.ObjectUtils;
 import org.apache.commons.lang3.StringUtils;
 import org.springframework.data.domain.Sort;
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
@@ -88,12 +89,16 @@ public class CategoryFinderImpl implements CategoryFinder {
 
     @Override
     public Flux<CategoryTreeVo> listAsTree() {
-        return this.toCategoryTreeVoFlux(null);
+        return listAll()
+            .collectList()
+            .flatMapMany(list -> Flux.fromIterable(listToTree(list, null)));
     }
 
     @Override
     public Flux<CategoryTreeVo> listAsTree(String name) {
-        return this.toCategoryTreeVoFlux(name);
+        return listAllFor(name)
+            .collectList()
+            .flatMapMany(list -> Flux.fromIterable(listToTree(list, name)));
     }
 
     @Override
@@ -103,19 +108,27 @@ public class CategoryFinderImpl implements CategoryFinder {
             .map(CategoryVo::from);
     }
 
-    Flux<CategoryVo> listAllFor(String parentName) {
-        return categoryService.isCategoryHidden(parentName)
+    private Flux<CategoryVo> listAllFor(String parentName) {
+        return Mono.defer(
+                () -> {
+                    if (StringUtils.isBlank(parentName)) {
+                        return Mono.just(false);
+                    }
+                    return categoryService.isCategoryHidden(parentName);
+                })
             .flatMapMany(
                 isHidden -> client.listAll(Category.class, new ListOptions(), defaultSort())
-                    .filter(category -> isHidden || !category.getSpec().isHideFromList())
+                    .filter(category -> {
+                        if (isHidden) {
+                            return true;
+                        }
+                        return !category.getSpec().isHideFromList();
+                    })
                     .map(CategoryVo::from)
             );
     }
 
-    Flux<CategoryTreeVo> toCategoryTreeVoFlux(String name) {
-        return listAllFor(name)
-            .collectList()
-            .flatMapIterable(categoryVos -> {
+    private List<CategoryTreeVo> listToTree(List<CategoryVo> categoryVos, @Nullable String name) {
         Map<String, CategoryTreeVo> nameIdentityMap = categoryVos.stream()
             .map(CategoryTreeVo::from)
             .collect(Collectors.toMap(categoryVo -> categoryVo.getMetadata().getName(),
@@ -136,10 +149,9 @@ public class CategoryFinderImpl implements CategoryFinder {
         var tree = listToTree(nameIdentityMap.values(), name);
         recomputePostCount(tree);
         return tree;
-            });
     }
 
-    static List<CategoryTreeVo> listToTree(Collection<CategoryTreeVo> list, String name) {
+    private static List<CategoryTreeVo> listToTree(Collection<CategoryTreeVo> list, String name) {
         Map<String, List<CategoryTreeVo>> parentNameIdentityMap = list.stream()
             .filter(categoryTreeVo -> categoryTreeVo.getParentName() != null)
             .collect(Collectors.groupingBy(CategoryTreeVo::getParentName));
@@ -228,8 +240,9 @@ public class CategoryFinderImpl implements CategoryFinder {
 
     @Override
     public Flux<CategoryVo> getBreadcrumbs(String name) {
-        return listAsTree()
+        return listAllFor(name)
             .collectList()
+            .map(list -> listToTree(list, null))
             .flatMapMany(treeNodes -> {
                 var rootNode = dummyVirtualRoot(treeNodes);
                 var paths = new ArrayList<CategoryVo>();

application/src/test/java/run/halo/app/theme/finders/impl/CategoryFinderImplTest.java

@@ -13,6 +13,8 @@ import java.time.Instant;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
+import java.util.function.Function;
+import java.util.stream.Collectors;
 import org.json.JSONException;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Nested;
@@ -190,13 +192,13 @@ class CategoryFinderImplTest {
             var json = Files.readString(file.toPath());
             categories = JsonUtils.jsonToObject(json, new TypeReference<>() {
             });
-            when(client.listAll(eq(Category.class), any(ListOptions.class), any(Sort.class)))
-                .thenReturn(Flux.fromIterable(categories));
         }
 
         @Test
         void computePostCountFromTree() {
-            var treeVos = categoryFinder.toCategoryTreeVoFlux("全部")
+            when(client.listAll(eq(Category.class), any(ListOptions.class), any(Sort.class)))
+                .thenReturn(Flux.fromIterable(categories));
+            var treeVos = categoryFinder.listAsTree("全部")
                 .collectList().block();
             assertThat(treeVos).hasSize(1);
             String s = visualizeTree(treeVos.get(0).getChildren());
@@ -232,6 +234,8 @@ class CategoryFinderImplTest {
 
         @Test
         void getBreadcrumbsTest() {
+            when(client.listAll(eq(Category.class), any(ListOptions.class), any(Sort.class)))
+                .thenReturn(Flux.fromIterable(categories));
             // first level
             var breadcrumbs = categoryFinder.getBreadcrumbs("全部").collectList().block();
             assertThat(toNames(breadcrumbs)).containsSequence("全部");
@@ -259,6 +263,26 @@ class CategoryFinderImplTest {
             assertThat(toNames(breadcrumbs)).isEmpty();
         }
 
+        @Test
+        void getBreadcrumbsForHiddenTest() {
+            Map<String, Category> categoryMap = categories.stream()
+                .collect(
+                    Collectors.toMap(item -> item.getMetadata().getName(), Function.identity()));
+            var category = categoryMap.get("IndependentNode");
+            category.getSpec().setHideFromList(true);
+            when(client.listAll(eq(Category.class), any(ListOptions.class), any(Sort.class)))
+                .thenReturn(Flux.fromIterable(categoryMap.values()));
+
+            when(categoryService.isCategoryHidden(eq("IndependentChild4")))
+                .thenReturn(Mono.just(true));
+
+            var breadcrumbs = categoryFinder.getBreadcrumbs("IndependentChild4")
+                .collectList().block();
+            assertThat(toNames(breadcrumbs)).containsSequence("全部", "FIT2CLOUD",
+                "IndependentNode",
+                "IndependentChild4");
+        }
+
         static List<String> toNames(List<CategoryVo> categories) {
             if (categories == null) {
                 return List.of();