Fix #16412: if a resource contains both staged and unstaged changes, selection in the SCM panel was not reliable

packages/git/src/browser/git-scm-provider.ts

@@ -144,6 +144,21 @@ export class GitScmProvider implements ScmProvider {
     get groups(): ScmResourceGroup[] {
         return this.state.groups;
     }
+
+    /**
+     * Find the group that contains the given URI.
+     * @param uri The URI to find.
+     * @returns The resource group that contains the URI, or undefined if not found.
+     */
+    getScmGroupIdForUri(uri: URI): string | undefined {
+        if (uri.query === 'HEAD') {
+            return 'workingTree';
+        } else if (uri.query === 'index') {
+            return 'index';
+        }
+        return undefined;
+    }
+
     get stagedChanges(): GitFileChange[] {
         return this.state.stagedChanges;
     }

packages/scm/src/browser/scm-provider.ts

@@ -1,4 +1,4 @@
-// *****************************************************************************
+// ***************************************************************************//
 // Copyright (C) 2019 Red Hat, Inc. and others.
 //
 // This program and the accompanying materials are made available under the
@@ -36,6 +36,13 @@ export interface ScmProvider extends Disposable {
     readonly onDidChangeCommitTemplate: Event<string>;
 
     readonly amendSupport?: ScmAmendSupport;
+
+    /**
+     * Returns the SCM resource group that contains the given URI, or undefined if not found.
+     * @param uri The URI to search for
+     * @returns The SCM resource group containing the URI, or undefined if not found
+     */
+    readonly getScmGroupIdForUri?: (uri: URI) => string | undefined;
 }
 
 export const ScmResourceGroup = Symbol('ScmResourceGroup');

packages/scm/src/browser/scm-tree-model.ts

@@ -79,7 +79,6 @@ export namespace ScmFileChangeNode {
 
 @injectable()
 export abstract class ScmTreeModel extends TreeModelImpl {
-
     private _languageId: string | undefined;
 
     protected provider: ScmProvider | undefined;
@@ -389,6 +388,13 @@ export abstract class ScmTreeModel extends TreeModelImpl {
         return this.groups.find(g => g.id === groupId);
     }
 
+    getScmGroupIdForUri(uri: URI): string | undefined {
+        if (this.provider?.getScmGroupIdForUri) {
+            return this.provider?.getScmGroupIdForUri(uri);
+        }
+        return undefined;
+    }
+
     // eslint-disable-next-line @typescript-eslint/no-explicit-any
     override storeState(): any {
         return {

packages/scm/src/browser/scm-tree-widget.tsx

@@ -361,7 +361,12 @@ export class ScmTreeWidget extends TreeWidget {
     }
 
     selectNodeByUri(uri: URI): void {
+        const groupId = this.model.getScmGroupIdForUri(uri);
         for (const group of this.model.groups) {
+            if (groupId && group.id !== groupId) {
+                continue;
+            }
+
             const sourceUri = new URI(uri.path.toString());
             const id = `${group.id}:${sourceUri.toString()}`;
             const node = this.model.getNode(id);