From 980aef736126e6ccf23cb053a44981ab4540162b Mon Sep 17 00:00:00 2001
From: Alitzel Mendez Bustillo <almend@microsoft.com>
Date: Fri, 25 Oct 2024 10:43:59 -0700
Subject: [PATCH 1/2] Fix x-ms-identifiers-linter-rule

---
 .../src/rules/missing-x-ms-identifiers.ts     | 28 +++++++++++++------
 .../rules/missing-x-ms-identifiers.test.ts    | 25 +++++++++++++++++
 2 files changed, 44 insertions(+), 9 deletions(-)

diff --git a/packages/typespec-azure-resource-manager/src/rules/missing-x-ms-identifiers.ts b/packages/typespec-azure-resource-manager/src/rules/missing-x-ms-identifiers.ts
index 6784ff0ef6..d59153eedd 100644
--- a/packages/typespec-azure-resource-manager/src/rules/missing-x-ms-identifiers.ts
+++ b/packages/typespec-azure-resource-manager/src/rules/missing-x-ms-identifiers.ts
@@ -58,19 +58,29 @@ export const missingXmsIdentifiersRule = createRule({
       }
 
       if (Array.isArray(xmsIdentifiers)) {
-        for (const prop of xmsIdentifiers) {
-          if (typeof prop === "string") {
-            if (getProperty(elementType, prop) === undefined) {
-              context.reportDiagnostic({
-                messageId: "missingProperty",
-                format: { propertyName: prop, targetModelName: elementType.name },
-                target: property,
-              });
+        for (const propIdentifier of xmsIdentifiers) {
+          if (typeof propIdentifier === "string") {
+            const props = propIdentifier.split("/");
+            let element = elementType;
+            for (const prop of props) {
+              const propertyValue = getProperty(element, prop);
+              if (propertyValue === undefined) {
+                context.reportDiagnostic({
+                  messageId: "missingProperty",
+                  format: { propertyName: prop, targetModelName: elementType.name },
+                  target: property,
+                });
+              }
+
+              const propertyType = propertyValue?.type as ArrayModelType;
+              if (propertyType !== undefined && propertyType.kind === "Model") {
+                element = propertyType;
+              }
             }
           } else {
             context.reportDiagnostic({
               messageId: "notArray",
-              format: { valueType: typeof prop },
+              format: { valueType: typeof propIdentifier },
               target: property,
             });
           }
diff --git a/packages/typespec-azure-resource-manager/test/rules/missing-x-ms-identifiers.test.ts b/packages/typespec-azure-resource-manager/test/rules/missing-x-ms-identifiers.test.ts
index d0bbe77c26..c3a7ff564b 100644
--- a/packages/typespec-azure-resource-manager/test/rules/missing-x-ms-identifiers.test.ts
+++ b/packages/typespec-azure-resource-manager/test/rules/missing-x-ms-identifiers.test.ts
@@ -130,4 +130,29 @@ describe("typespec-azure-core: no-enum rule", () => {
       )
       .toBeValid();
   });
+
+  it("allow array of x-ms-identifiers", async () => {
+    await tester
+      .expect(
+        `
+        model Pet {
+          @OpenAPI.extension("x-ms-identifiers", ["food/brand/name"])
+          pet: Dog[];
+        }
+ 
+        model Dog {
+          food: Food;
+        }
+        
+        model Food {
+          brand: Brand;
+        }
+        
+        model Brand {
+          name: string;
+        }
+        `,
+      )
+      .toBeValid();
+  });
 });

From b7bbc85544035912afc58e9b2907656f98ce5a62 Mon Sep 17 00:00:00 2001
From: Alitzel Mendez Bustillo <almend@microsoft.com>
Date: Fri, 25 Oct 2024 10:51:24 -0700
Subject: [PATCH 2/2] summary of changes

---
 .../fix-x-ms-identifiers-rule-2024-9-25-10-44-57.md        | 7 +++++++
 1 file changed, 7 insertions(+)
 create mode 100644 .chronus/changes/fix-x-ms-identifiers-rule-2024-9-25-10-44-57.md

diff --git a/.chronus/changes/fix-x-ms-identifiers-rule-2024-9-25-10-44-57.md b/.chronus/changes/fix-x-ms-identifiers-rule-2024-9-25-10-44-57.md
new file mode 100644
index 0000000000..6a7ca145ea
--- /dev/null
+++ b/.chronus/changes/fix-x-ms-identifiers-rule-2024-9-25-10-44-57.md
@@ -0,0 +1,7 @@
+---
+changeKind: fix
+packages:
+  - "@azure-tools/typespec-azure-resource-manager"
+---
+
+Fix the `x-ms-identifier` rule. The `x-ms-identifier` supports indexing into inner properties, but the linter does not support that and reports a warning.