fix(sentry-dart): remove transitive dart:io reference for web (#1898)

* fix(sentry-dart): remove transitive dart:io reference for web

TransportUtils imported sentry_io.dart which prevented web
projects such as example_web from building when build_runner
was used.

Resolves #1893

* docs(api): update CHANGELOG.md for unreleased fix

CHANGELOG.md now includes information about unreleased fix for
issue #1893.

* test(dart-sentry): add compilation tests for example_web

Added tests to check if example_web project can be compiled with
build_runner.

Resolves #1893

* test(dart-sentry): fix failing tests for example_web compilation

Test ordering should not have impact on example_web_comopile_test
and path handling across platforms was simplified.

Resolves #1893

* docs(api): update CHANGELOG.md

Place entry for #1893 under unreleased fix in CHANGELOG

#1893

* chore(code-style): code formatting for #1893

Author: daniel-v

CHANGELOG.md

@@ -6,6 +6,7 @@
 
 - Fix transaction end timestamp trimming ([#1916](https://github.com/getsentry/sentry-dart/pull/1916))
   - Transaction end timestamps are now correctly trimmed to the latest child span end timestamp
+- remove transitive dart:io reference for web ([#1898](https://github.com/getsentry/sentry-dart/pull/1898))  
 
 ### Features
 

dart/lib/src/utils/transport_utils.dart

@@ -1,7 +1,9 @@
 import 'package:http/http.dart';
 
-import '../../sentry_io.dart';
 import '../client_reports/discard_reason.dart';
+import '../protocol.dart';
+import '../sentry_envelope.dart';
+import '../sentry_options.dart';
 import '../transport/data_category.dart';
 
 class TransportUtils {

dart/test/example_web_compile_test.dart

@@ -0,0 +1,86 @@
+@TestOn('vm')
+import 'dart:async';
+import 'dart:convert';
+import 'dart:io';
+
+import 'package:test/test.dart';
+
+// Tests for the following issue
+// https://github.com/getsentry/sentry-dart/issues/1893
+void main() {
+  group('Compile example_web', () {
+    test(
+      'dart pub get and compilation should run successfully',
+      () async {
+        final result = await _runProcess('dart pub get',
+            workingDirectory: _exampleWebWorkingDir);
+        expect(result.exitCode, 0,
+            reason: 'Could run `dart pub get` for example_web. '
+                'Likely caused by outdated dependencies');
+        // running this test locally require clean working directory
+        final cleanResult = await _runProcess('dart run build_runner clean',
+            workingDirectory: _exampleWebWorkingDir);
+        expect(cleanResult.exitCode, 0);
+        final compileResult = await _runProcess(
+            'dart run build_runner build -r web -o build --delete-conflicting-outputs',
+            workingDirectory: _exampleWebWorkingDir);
+        expect(compileResult.exitCode, 0,
+            reason: 'Could not compile example_web project');
+        expect(
+            compileResult.stdout,
+            isNot(contains(
+                'Skipping compiling sentry_dart_web_example|web/main.dart')),
+            reason:
+                'Could not compile main.dart, likely because of dart:io import.');
+        expect(
+            compileResult.stdout,
+            contains(
+                'build_web_compilers:entrypoint on web/main.dart:Compiled'));
+      },
+      timeout: Timeout(const Duration(minutes: 1)), // double of detault timeout
+    );
+  });
+}
+
+/// Runs [command] with command's stdout and stderr being forwrarded to
+/// test runner's respective streams. It buffers stdout and returns it.
+///
+/// Returns [_CommandResult] with exitCode and stdout as a single sting
+Future<_CommandResult> _runProcess(String command,
+    {String workingDirectory = '.'}) async {
+  final parts = command.split(' ');
+  assert(parts.isNotEmpty);
+  final cmd = parts[0];
+  final args = parts.skip(1).toList();
+  final process =
+      await Process.start(cmd, args, workingDirectory: workingDirectory);
+  // forward standard streams
+  unawaited(stderr.addStream(process.stderr));
+  final buffer = <int>[];
+  final stdoutCompleter = Completer.sync();
+  process.stdout.listen(
+    (units) {
+      buffer.addAll(units);
+      stdout.add(units);
+    },
+    cancelOnError: true,
+    onDone: () {
+      stdoutCompleter.complete();
+    },
+  );
+  await stdoutCompleter.future;
+  final processOut = utf8.decode(buffer);
+  int exitCode = await process.exitCode;
+  return _CommandResult(exitCode: exitCode, stdout: processOut);
+}
+
+String get _exampleWebWorkingDir {
+  return '${Directory.current.path}${Platform.pathSeparator}example_web';
+}
+
+class _CommandResult {
+  final int exitCode;
+  final String stdout;
+
+  const _CommandResult({required this.exitCode, required this.stdout});
+}