[TCGC] Fix judge logic how to distinguish model is referred both in c…

…ommon content-type and multipart content-type (#1511)

fix #1510

---------

Co-authored-by: tadelesh <tadelesh.shi@live.cn>

.chronus/changes/fix-multipart-diagnostics-2024-8-13-13-31-25.md

@@ -0,0 +1,7 @@
+---
+changeKind: fix
+packages:
+  - "@azure-tools/typespec-client-generator-core"
+---
+
+Fix logic to check conflicting usage for model of multipart body and regular body

packages/typespec-client-generator-core/src/types.ts

@@ -1602,26 +1602,6 @@ function updateTypesFromOperation(
     }
 
     const multipartOperation = isMultipartOperation(context, operation);
-    // this part should be put before setting current body's usage because it is based on the previous usage
-    if (
-      sdkType.kind === "model" &&
-      ((!multipartOperation && (sdkType.usage & UsageFlags.MultipartFormData) > 0) ||
-        (multipartOperation &&
-          (sdkType.usage & UsageFlags.Input) > 0 &&
-          (sdkType.usage & UsageFlags.Input & UsageFlags.MultipartFormData) === 0))
-    ) {
-      // This means we have a model that is used both for formdata input and for regular body input
-      diagnostics.add(
-        createDiagnostic({
-          code: "conflicting-multipart-model-usage",
-          target: httpBody.type,
-          format: {
-            modelName: sdkType.name,
-          },
-        }),
-      );
-    }
-
     if (generateConvenient) {
       if (spread) {
         updateUsageOrAccessOfModel(context, UsageFlags.Spread, sdkType, { propagation: false });
@@ -1649,7 +1629,28 @@ function updateTypesFromOperation(
     }
     const access = getAccessOverride(context, operation) ?? "public";
     diagnostics.pipe(updateUsageOrAccessOfModel(context, access, sdkType));
+
+    // after completion of usage calculation for httpBody, check whether it has
+    // conflicting usage between multipart and regular body
+    if (sdkType.kind === "model") {
+      const isUsedInMultipart = (sdkType.usage & UsageFlags.MultipartFormData) > 0;
+      const isUsedInOthers =
+        ((sdkType.usage & UsageFlags.Json) | (sdkType.usage & UsageFlags.Xml)) > 0;
+      if ((!multipartOperation && isUsedInMultipart) || (multipartOperation && isUsedInOthers)) {
+        // This means we have a model that is used both for formdata input and for regular body input
+        diagnostics.add(
+          createDiagnostic({
+            code: "conflicting-multipart-model-usage",
+            target: httpBody.type,
+            format: {
+              modelName: sdkType.name,
+            },
+          }),
+        );
+      }
+    }
   }
+
   for (const response of httpOperation.responses) {
     for (const innerResponse of response.responses) {
       if (innerResponse.body?.type && !isNeverOrVoidType(innerResponse.body.type)) {

packages/typespec-client-generator-core/test/types/multipart-types.test.ts

@@ -55,6 +55,7 @@ describe("typespec-client-generator-core: multipart types", () => {
     ok(profileImage.multipartOptions);
     strictEqual(profileImage.multipartOptions.isFilePart, true);
   });
+
   it("multipart conflicting model usage", async function () {
     await runner.compile(
       `
@@ -72,6 +73,70 @@ describe("typespec-client-generator-core: multipart types", () => {
       code: "@azure-tools/typespec-client-generator-core/conflicting-multipart-model-usage",
     });
   });
+
+  it("multipart conflicting model usage for only multipart operations", async function () {
+    await runner.compile(
+      `
+        @service({title: "Test Service"}) namespace TestService;
+        model Address {city: string;}
+        model MultiPartRequest {
+          address: Address;
+          id: string;
+          profileImage: bytes;
+        }
+        
+        @post
+        @route("/basic1") 
+        op basic1(@header contentType: "multipart/form-data", @body body: MultiPartRequest): NoContentResponse;
+        @post
+        @route("/basic2") 
+        op basic2(@header contentType: "multipart/form-data", @body body: MultiPartRequest): NoContentResponse;
+      `,
+    );
+    deepEqual(runner.context.diagnostics.length, 0);
+    const address = runner.context.sdkPackage.models.find((x) => x.name === "Address");
+    ok(address);
+    deepEqual(address.usage, UsageFlags.Input);
+    const multiPartRequest = runner.context.sdkPackage.models.find(
+      (x) => x.name === "MultiPartRequest",
+    );
+    ok(multiPartRequest);
+    deepEqual(multiPartRequest.usage, UsageFlags.MultipartFormData | UsageFlags.Input);
+  });
+
+  it("multipart conflicting model usage for mixed operations", async function () {
+    await runner.compile(
+      `
+        @service({title: "Test Service"}) namespace TestService;
+        model Address {city: string;}
+        model RegularRequest {
+          address: Address;
+        }
+        model MultiPartRequest {
+          address: Address;
+          id: string;
+          profileImage: bytes;
+        }
+        
+        @post
+        @route("/basic1") 
+        op basic1(@body body: RegularRequest): NoContentResponse;
+        @post
+        @route("/basic2") 
+        op basic2(@header contentType: "multipart/form-data", @body body: MultiPartRequest): NoContentResponse;
+      `,
+    );
+    deepEqual(runner.context.diagnostics.length, 0);
+    const address = runner.context.sdkPackage.models.find((x) => x.name === "Address");
+    ok(address);
+    deepEqual(address.usage, UsageFlags.Input | UsageFlags.Json);
+    const multiPartRequest = runner.context.sdkPackage.models.find(
+      (x) => x.name === "MultiPartRequest",
+    );
+    ok(multiPartRequest);
+    deepEqual(multiPartRequest.usage, UsageFlags.MultipartFormData | UsageFlags.Input);
+  });
+
   it("multipart resolving conflicting model usage with spread", async function () {
     await runner.compileWithBuiltInService(
       `