From 8112e2a3d2591c922a4faeaa63f66064a6102609 Mon Sep 17 00:00:00 2001
From: Zach Arend <zachzach@google.com>
Date: Fri, 6 Oct 2023 18:17:16 +0000
Subject: [PATCH] DEPRECATED:  - MatTreeFlatDataSource deprecated. Use
 levelAccessor or    childrenAccessor instead of TreeController

---
 src/material/tree/data-source/flat-data-source.ts | 4 ++++
 tools/public_api_guard/material/tree.md           | 2 +-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/material/tree/data-source/flat-data-source.ts b/src/material/tree/data-source/flat-data-source.ts
index 1763019ef080..ab1777333bb6 100644
--- a/src/material/tree/data-source/flat-data-source.ts
+++ b/src/material/tree/data-source/flat-data-source.ts
@@ -122,6 +122,10 @@ export class MatTreeFlattener<T, F, K = F> {
  * to `MatTree`.
  * The nested tree nodes of type `T` are flattened through `MatTreeFlattener`, and converted
  * to type `F` for `MatTree` to consume.
+ *
+ * @deprecated Use one of levelAccessor or childrenAccessor instead. To be removed in a future
+ * version.
+ * @breaking-change 19.0.0
  */
 export class MatTreeFlatDataSource<T, F, K = F> extends DataSource<F> {
   private readonly _flattenedData = new BehaviorSubject<F[]>([]);
diff --git a/tools/public_api_guard/material/tree.md b/tools/public_api_guard/material/tree.md
index df212e6c2618..6d4bd522e956 100644
--- a/tools/public_api_guard/material/tree.md
+++ b/tools/public_api_guard/material/tree.md
@@ -64,7 +64,7 @@ export class MatTree<T, K = T> extends CdkTree<T, K> {
     static ɵfac: i0.ɵɵFactoryDeclaration<MatTree<any, any>, never>;
 }
 
-// @public
+// @public @deprecated
 export class MatTreeFlatDataSource<T, F, K = F> extends DataSource<F> {
     constructor(_treeControl: FlatTreeControl<F, K>, _treeFlattener: MatTreeFlattener<T, F, K>, initialData?: T[]);
     // (undocumented)