From 82c436d2513c9c9ae1193135fca3df9fbded5fce Mon Sep 17 00:00:00 2001
From: Andrey Vorobev <738482+vorobey@users.noreply.github.com>
Date: Thu, 16 Jul 2026 16:25:48 +0300
Subject: [PATCH] AngularWrapper: fix nested legacy warnings (#34338)

---
 .../src/core/deprecated-config-warning.ts     |  4 +-
 .../core/deprecated-config-warning.spec.ts    | 54 +++++++++++++++++++
 2 files changed, 56 insertions(+), 2 deletions(-)
 create mode 100644 packages/devextreme-angular/tests/src/core/deprecated-config-warning.spec.ts

diff --git a/packages/devextreme-angular/src/core/deprecated-config-warning.ts b/packages/devextreme-angular/src/core/deprecated-config-warning.ts
index 5b82790eb259..1e41fd3ca966 100644
--- a/packages/devextreme-angular/src/core/deprecated-config-warning.ts
+++ b/packages/devextreme-angular/src/core/deprecated-config-warning.ts
@@ -5,7 +5,7 @@ import { logWarning } from './warning-helper';
 
 const warnedUsages = new Set<string>();
 
-const NESTED_CLASS_NAME_REGEXP = /^(Dx[io][A-Z]\w+)Component$/;
+const NESTED_CLASS_NAME_REGEXP = /^_*(Dx[io][A-Z]\w+)Component$/;
 
 type DeprecatedConfigEntry = Record<string, string>;
 
@@ -32,7 +32,7 @@ function getHostMapping(host: INestedOptionContainer | undefined): DeprecatedCon
   while (current && !visited.has(current)) {
     visited.add(current);
 
-    const ctorName = current.constructor?.name;
+    const ctorName = current.constructor?.name?.replace(/^_+/, '');
     if (ctorName && Object.prototype.hasOwnProperty.call(DEPRECATED_CONFIG_COMPONENTS, ctorName)) {
       return DEPRECATED_CONFIG_COMPONENTS[ctorName] as DeprecatedConfigEntry;
     }
diff --git a/packages/devextreme-angular/tests/src/core/deprecated-config-warning.spec.ts b/packages/devextreme-angular/tests/src/core/deprecated-config-warning.spec.ts
new file mode 100644
index 000000000000..c79397fc4a49
--- /dev/null
+++ b/packages/devextreme-angular/tests/src/core/deprecated-config-warning.spec.ts
@@ -0,0 +1,54 @@
+import { NestedOptionHost } from 'devextreme-angular';
+
+// The warning is reached through NestedOptionHost.setNestedOption(), so these
+// tests drive the real integration point rather than the internal helper.
+//
+// esbuild renames a class that self-references in its decorator metadata to
+// `_ClassName`, so at runtime `constructor.name` is `_DxiItemComponent` /
+// `_DxAccordionComponent`. We fake that here to lock in the underscore-tolerant
+// lookup in getLegacySelector (regex) and getHostMapping (map key normalization).
+
+function fakeHost(ctorName: string): any {
+  return { constructor: { name: ctorName } };
+}
+
+function fakeNestedOption(ctorName: string): any {
+  return {
+    constructor: { name: ctorName },
+    // setNestedOption calls this before warning; a no-op is enough.
+    setHost() {},
+  };
+}
+
+describe('deprecated nested config warning', () => {
+  let warnSpy: jasmine.Spy;
+
+  beforeEach(() => {
+    warnSpy = spyOn(console, 'warn');
+  });
+
+  it('resolves the legacy mapping and warns exactly once when esbuild prefixes class names with "_"', () => {
+    const host = new NestedOptionHost();
+    host.setHost(fakeHost('_DxAccordionComponent'));
+
+    // Register the same legacy usage twice: the cache must collapse it to one warning.
+    host.setNestedOption(fakeNestedOption('_DxiItemComponent'));
+    host.setNestedOption(fakeNestedOption('_DxiItemComponent'));
+
+    expect(warnSpy).toHaveBeenCalledTimes(1);
+
+    const message = warnSpy.calls.mostRecent().args[0] as string;
+    expect(message).toContain('W3001');
+    expect(message).toContain('legacy dxi-item');
+    expect(message).toContain('dxi-accordion-item');
+  });
+
+  it('does not warn when the new named configuration component is used', () => {
+    const host = new NestedOptionHost();
+    host.setHost(fakeHost('_DxAccordionComponent'));
+
+    host.setNestedOption(fakeNestedOption('_DxiAccordionItemComponent'));
+
+    expect(warnSpy).not.toHaveBeenCalled();
+  });
+});