[ARM Incremental TypeSpec] Fail if file is deleted (#32905)

.github/workflows/src/arm-incremental-typespec-preview.js

@@ -25,7 +25,19 @@ export default async function incrementalTypeSpec({ github, context, core }) {
 
   // If any changed file is not typespec-generated, return false
   for (const file of changedRmSwaggerFiles) {
-    const swagger = await show("HEAD", file, core);
+    let swagger;
+    try {
+      swagger = await show("HEAD", file, core);
+    } catch (e) {
+      if (e instanceof Error && e.message.includes("does not exist")) {
+        // To simplify logic, if PR deletes a swagger file, it's not "incremental typespec"
+        core.info(`File "${file}" has been deleted`);
+        return false;
+      } else {
+        // Unknown error
+        throw e;
+      }
+    }
 
     const swaggerObj = JSON.parse(swagger);
 

.github/workflows/test/arm-incremental-typespec-preview.test.js

@@ -6,6 +6,8 @@ import * as git from "../src/git.js";
 
 const core = createMockCore();
 
+const swaggerHandWritten = JSON.stringify("foo");
+
 const swaggerTypeSpecGenerated = JSON.stringify({
   info: {
     "x-typespec-generated": [{ emitter: "@azure-tools/typespec-autorest" }],
@@ -35,7 +37,7 @@ describe("incrementalTypeSpec", () => {
       "getChangedResourceManagerSwaggerFiles",
     ).mockResolvedValue([swaggerPath]);
 
-    vi.spyOn(git, "show").mockResolvedValue('"foo"');
+    vi.spyOn(git, "show").mockResolvedValue(swaggerHandWritten);
 
     await expect(incrementalTypeSpec({ core })).resolves.toBe(false);
   });
@@ -57,6 +59,60 @@ describe("incrementalTypeSpec", () => {
     await expect(incrementalTypeSpec({ core })).resolves.toBe(false);
   });
 
+  it("returns false if swagger deleted", async () => {
+    const swaggerPath =
+      "/specification/contosowidgetmanager/resource-manager/Microsoft.Contoso/preview/2021-10-01-preview/contoso.json";
+
+    vi.spyOn(
+      changedFiles,
+      "getChangedResourceManagerSwaggerFiles",
+    ).mockResolvedValue([swaggerPath]);
+
+    vi.spyOn(git, "show").mockRejectedValue(
+      new Error("path contoso.json does not exist in 'HEAD'"),
+    );
+
+    await expect(incrementalTypeSpec({ core })).resolves.toBe(false);
+  });
+
+  it("returns false if tsp conversion", async () => {
+    const swaggerPath =
+      "/specification/contosowidgetmanager/resource-manager/Microsoft.Contoso/preview/2021-10-01-preview/contoso.json";
+
+    vi.spyOn(
+      changedFiles,
+      "getChangedResourceManagerSwaggerFiles",
+    ).mockResolvedValue([swaggerPath]);
+
+    vi.spyOn(git, "show").mockImplementation((treeIsh) =>
+      treeIsh == "HEAD" ? swaggerTypeSpecGenerated : swaggerHandWritten,
+    );
+
+    vi.spyOn(git, "lsTree").mockImplementation(
+      async (_treeIsh, _path, _core, options) => {
+        return options?.includes("-r --name-only")
+          ? swaggerPath.substring(1)
+          : "040000 tree abc123 specification/contosowidgetmanager";
+      },
+    );
+
+    await expect(incrementalTypeSpec({ core })).resolves.toBe(false);
+  });
+
+  it("throws if git show returns unknown error", async () => {
+    const swaggerPath =
+      "/specification/contosowidgetmanager2/resource-manager/Microsoft.Contoso/preview/2021-10-01-preview/contoso.json";
+
+    vi.spyOn(
+      changedFiles,
+      "getChangedResourceManagerSwaggerFiles",
+    ).mockResolvedValue([swaggerPath]);
+
+    vi.spyOn(git, "show").mockRejectedValue("string error");
+
+    await expect(incrementalTypeSpec({ core })).rejects.toThrowError();
+  });
+
   it("returns true if changed files are incremental changes to an existing TypeSpec RP", async () => {
     const swaggerPath =
       "/specification/contosowidgetmanager/resource-manager/Microsoft.Contoso/preview/2021-10-01-preview/contoso.json";