fix(cli): guard nil file panic in generated download commands

clients/cli/spec/locales_download_spec.rb

@@ -0,0 +1,57 @@
+require "spec_helper"
+
+RSpec.describe "phrase locales download" do
+  let(:token) { "test-token-locales-download" }
+  let(:project_id) { "test-project-456" }
+  let(:locale_id) { "en-US" }
+
+  before do
+    mock_clear_requests!
+  end
+
+  # The API responds with 200 and an empty body when a --tags filter
+  # matches zero translations. This used to crash the generated
+  # "locales download" command with a nil pointer dereference, because
+  # it unconditionally called Close()/Name() on the (nil) result file.
+  it "does not crash when a tag filter matches no translations" do
+    mock_set!("GET", "/projects/#{project_id}/locales/#{locale_id}/download",
+      status: 200,
+      body: "",
+      headers: { "content-type" => "application/x-properties" }
+    )
+
+    r = run_cli(
+      "locales", "download",
+      "--id", locale_id,
+      "--project_id", project_id,
+      "--file_format", "properties",
+      "--tags", "nonexistent-tag",
+      "-t", token,
+      "--host", ENV.fetch("BASE_URL")
+    )
+
+    expect(r[:stderr]).not_to include("panic")
+    expect(r[:exit_code]).to eq(0)
+    expect(r[:stdout]).to eq("")
+  end
+
+  it "still prints the downloaded content for a normal response" do
+    mock_set!("GET", "/projects/#{project_id}/locales/#{locale_id}/download",
+      status: 200,
+      body: "hello=world",
+      headers: { "content-type" => "application/x-properties" }
+    )
+
+    r = run_cli(
+      "locales", "download",
+      "--id", locale_id,
+      "--project_id", project_id,
+      "--file_format", "properties",
+      "-t", token,
+      "--host", ENV.fetch("BASE_URL")
+    )
+
+    expect(r[:exit_code]).to eq(0)
+    expect(r[:stdout]).to include("hello=world")
+  end
+end

openapi-generator/templates/cli/api.handlebars

@@ -127,10 +127,12 @@ func init{{{nickname}}}() {
 						HandleError(castedError)
 				}
 			} else if api_response.StatusCode >= 200 && api_response.StatusCode < 300 {
-				{{#if returnType}}{{#if (eq returnType "*os.File")}}content, _ := ioutil.ReadAll(data)
-				fmt.Printf("%s", string(content))
-				data.Close()
-				os.Remove(data.Name()){{else}}jsonBuf, jsonErr := json.MarshalIndent(data, "", " ")
+				{{#if returnType}}{{#if (eq returnType "*os.File")}}if data != nil {
+					content, _ := ioutil.ReadAll(data)
+					fmt.Printf("%s", string(content))
+					data.Close()
+					os.Remove(data.Name())
+				}{{else}}jsonBuf, jsonErr := json.MarshalIndent(data, "", " ")
 				if jsonErr != nil {
 					fmt.Printf("%v\n", data)
 					HandleError(err)