unit test for issue #1783

tests/comp_import_extend.js

@@ -0,0 +1,18 @@
+"use strict";
+exports.__esModule = true;
+var path = require("path");
+var tape = require("tape");
+var protobuf = require("../index");
+// to extend Root
+require("../ext/descriptor");
+tape.test("extensions", function (test) {
+    // load document with extended field imported multiple times
+    var root = protobuf.loadSync(path.resolve(__dirname, "data/test-import-extend/main.proto"));
+    root.resolveAll();
+    // convert to Descriptor Set
+    var decodedDescriptorSet = root.toDescriptor("proto3");
+    // load back from descriptor set
+    var root2 = protobuf.Root.fromDescriptor(decodedDescriptorSet);
+    test.pass("should parse and resolve without errors");
+    test.end();
+});

tests/comp_import_extend.ts

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+import path = require("path");
+import * as tape from "tape";
+
+import * as protobuf from "../index";
+import { IFileDescriptorSet } from "../ext/descriptor";
+// to extend Root
+require("../ext/descriptor");
+
+interface Descriptor {
+  toDescriptor(
+    protoVersion: string
+  ): protobuf.Message<IFileDescriptorSet> & IFileDescriptorSet;
+  fromDescriptor(
+    descriptor: IFileDescriptorSet | protobuf.Reader | Uint8Array
+  ): protobuf.Root;
+}
+
+tape.test("extensions", function (test) {
+  // load document with extended field imported multiple times
+  const root = protobuf.loadSync(
+    path.resolve(__dirname, "data/test-import-extend/main.proto")
+  );
+  root.resolveAll();
+
+  // convert to Descriptor Set
+  const decodedDescriptorSet = (root as unknown as Descriptor).toDescriptor(
+    "proto3"
+  );
+
+  // load back from descriptor set
+  const root2 = (protobuf.Root as unknown as Descriptor).fromDescriptor(
+    decodedDescriptorSet
+  );
+
+  test.pass("should parse and resolve without errors");
+  test.end();
+});

tests/data/test-import-extend/main.proto

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+syntax = "proto3";
+
+package test.import.extend;
+
+import "source_a.proto";
+import "source_b.proto";

tests/data/test-import-extend/source_a.proto

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+syntax = "proto3";
+
+package source.a;
+
+import "validation.proto";

tests/data/test-import-extend/source_b.proto

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+syntax = "proto3";
+
+package source.b;
+
+import "validation.proto";

tests/data/test-import-extend/validation.proto

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+syntax = "proto3";
+
+package validation;
+
+import "../google/protobuf/descriptor.proto";
+
+option java_package = "com.reserve.validation";
+option java_outer_classname = "ValidationRules";
+
+extend google.protobuf.FieldOptions { FieldRules rules = 70001; }
+
+message FieldRules {
+  reserved 1;
+  reserved "optional";
+}