fix(mason_logger): only animate progress on terminals (#582)

.github/workflows/mason_logger.yaml

@@ -36,6 +36,18 @@ jobs:
       - name: Analyze
         run: dart analyze --fatal-infos --fatal-warnings .
 
+      - name: Verify CI Behavior
+        run: |
+          dart test/ci.dart >> ci.txt
+          actual="ci.txt"
+          expected="test/fixtures/ci.txt"
+          if cmp -s "$actual" "$expected"; then
+              echo "PASSED"
+          else
+              echo "FAILED"
+              exit 1
+          fi
+
       - name: Run Tests
         run: |
           dart pub global activate coverage 1.2.0

packages/mason_logger/lib/src/mason_logger.dart

@@ -3,6 +3,7 @@ import 'dart:convert';
 import 'dart:io' as io;
 
 import 'package:mason_logger/mason_logger.dart';
+import 'package:mason_logger/src/stdio_overrides.dart';
 
 part 'progress.dart';
 

packages/mason_logger/lib/src/progress.dart

@@ -51,6 +51,19 @@ class Progress {
     _stopwatch
       ..reset()
       ..start();
+
+    final stdioType = StdioOverrides.current?.stdioType ?? io.stdioType;
+
+    // The animation is only shown when it would be meaningful.
+    // Do not animate if the stdio type is not a terminal.
+    if (stdioType(_stdout) != io.StdioType.terminal) {
+      final frames = _options.animation.frames;
+      final char = frames.isEmpty ? '' : frames.first;
+      final prefix = char.isEmpty ? char : '${lightGreen.wrap(char)} ';
+      _write('$prefix$_message...');
+      return;
+    }
+
     _timer = Timer.periodic(const Duration(milliseconds: 80), _onTick);
   }
 
@@ -62,7 +75,7 @@ class Progress {
 
   final Stopwatch _stopwatch;
 
-  late final Timer _timer;
+  Timer? _timer;
 
   String _message;
 
@@ -74,26 +87,26 @@ class Progress {
     _write(
       '''$_clearLine${lightGreen.wrap('✓')} ${update ?? _message} $_time\n''',
     );
-    _timer.cancel();
+    _timer?.cancel();
   }
 
   /// End the progress and mark it as failed.
   void fail([String? update]) {
-    _timer.cancel();
+    _timer?.cancel();
     _write('$_clearLine${red.wrap('✗')} ${update ?? _message} $_time\n');
     _stopwatch.stop();
   }
 
   /// Update the progress message.
   void update(String update) {
-    _write(_clearLine);
+    if (_timer != null) _write(_clearLine);
     _message = update;
     _onTick(_timer);
   }
 
   /// Cancel the progress and remove the written line.
   void cancel() {
-    _timer.cancel();
+    _timer?.cancel();
     _write(_clearLine);
     _stopwatch.stop();
   }
@@ -103,7 +116,7 @@ class Progress {
         '\r'; // bring cursor to the start of the current line
   }
 
-  void _onTick(Timer _) {
+  void _onTick(Timer? _) {
     _index++;
     final frames = _options.animation.frames;
     final char = frames.isEmpty ? '' : frames[_index % frames.length];

packages/mason_logger/lib/src/stdio_overrides.dart

@@ -0,0 +1,49 @@
+import 'dart:async';
+import 'dart:io' as io;
+
+const _asyncRunZoned = runZoned;
+
+/// This class facilitates overriding [io.stdioType].
+abstract class StdioOverrides {
+  static final _token = Object();
+
+  /// Returns the current [StdioOverrides] instance.
+  ///
+  /// This will return `null` if the current [Zone] does not contain
+  /// any [StdioOverrides].
+  ///
+  /// See also:
+  /// * [StdioOverrides.runZoned] to provide [StdioOverrides]
+  /// in a fresh [Zone].
+  ///
+  static StdioOverrides? get current {
+    return Zone.current[_token] as StdioOverrides?;
+  }
+
+  /// Runs [body] in a fresh [Zone] using the provided overrides.
+  static R runZoned<R>(
+    R Function() body, {
+    io.StdioType Function(dynamic object) Function()? stdioType,
+  }) {
+    final overrides = _StdioOverridesScope(stdioType);
+    return _asyncRunZoned(
+      body,
+      zoneValues: {_token: overrides},
+    );
+  }
+
+  /// The [io.stdioType] that will be used for errors within the current [Zone].
+  io.StdioType Function(dynamic object) get stdioType => io.stdioType;
+}
+
+class _StdioOverridesScope extends StdioOverrides {
+  _StdioOverridesScope(this._stdioType);
+
+  final StdioOverrides? _previous = StdioOverrides.current;
+  final io.StdioType Function(dynamic object) Function()? _stdioType;
+
+  @override
+  io.StdioType Function(dynamic object) get stdioType {
+    return _stdioType?.call() ?? _previous?.stdioType ?? super.stdioType;
+  }
+}

packages/mason_logger/test/ci.dart

@@ -0,0 +1,12 @@
+import 'package:mason_logger/mason_logger.dart';
+
+Future<void> main() async {
+  final logger = Logger();
+  final progress = logger.progress('Calculating');
+  await Future<void>.delayed(const Duration(seconds: 1));
+  progress.update('This is taking longer than expected');
+  await Future<void>.delayed(const Duration(seconds: 1));
+  progress.update('Almost done');
+  await Future<void>.delayed(const Duration(seconds: 1));
+  progress.complete('Done');
+}

packages/mason_logger/test/fixtures/ci.txt

@@ -0,0 +1 @@
+⠋ Calculating...⠙ This is taking longer than expected... (1.0s)⠹ Almost done... (2.0s)✓ Done (3.0s)