Add offline mode

Author: RossComputerGuy

webdev/lib/src/command/configuration.dart

@@ -37,6 +37,7 @@ const nullSafetyAuto = 'auto';
 const disableDdsFlag = 'disable-dds';
 const enableExperimentOption = 'enable-experiment';
 const canaryFeaturesFlag = 'canary';
+const offlineFlag = 'offline';
 
 ReloadConfiguration _parseReloadConfiguration(ArgResults argResults) {
   var auto = argResults.options.contains(autoOption)
@@ -107,6 +108,7 @@ class Configuration {
   final String? _nullSafety;
   final List<String>? _experiments;
   final bool? _canaryFeatures;
+  final bool? _offline;
 
   Configuration({
     bool? autoRun,
@@ -133,6 +135,7 @@ class Configuration {
     String? nullSafety,
     List<String>? experiments,
     bool? canaryFeatures,
+    bool? offline,
   })  : _autoRun = autoRun,
         _chromeDebugPort = chromeDebugPort,
         _debugExtension = debugExtension,
@@ -154,7 +157,8 @@ class Configuration {
         _verbose = verbose,
         _nullSafety = nullSafety,
         _experiments = experiments,
-        _canaryFeatures = canaryFeatures {
+        _canaryFeatures = canaryFeatures,
+        _offline = offline {
     _validateConfiguration();
   }
 
@@ -229,7 +233,8 @@ class Configuration {
       verbose: other._verbose ?? _verbose,
       nullSafety: other._nullSafety ?? _nullSafety,
       experiments: other._experiments ?? _experiments,
-      canaryFeatures: other._canaryFeatures ?? _canaryFeatures);
+      canaryFeatures: other._canaryFeatures ?? _canaryFeatures,
+      offline: other._offline ?? _offline);
 
   factory Configuration.noInjectedClientDefaults() =>
       Configuration(autoRun: false, debug: false, debugExtension: false);
@@ -284,6 +289,8 @@ class Configuration {
 
   bool get canaryFeatures => _canaryFeatures ?? false;
 
+  bool get offline => _offline ?? false;
+
   /// Returns a new configuration with values updated from the parsed args.
   static Configuration fromArgs(ArgResults? argResults,
       {Configuration? defaultConfiguration}) {
@@ -408,6 +415,10 @@ class Configuration {
         ? argResults[canaryFeaturesFlag] as bool?
         : defaultConfiguration.canaryFeatures;
 
+    var offline = argResults.options.contains(offlineFlag)
+        ? argResults[offlineFlag] as bool?
+        : defaultConfiguration.verbose;
+
     return Configuration(
       autoRun: defaultConfiguration.autoRun,
       chromeDebugPort: chromeDebugPort,
@@ -433,6 +444,7 @@ class Configuration {
       nullSafety: nullSafety,
       experiments: experiments,
       canaryFeatures: canaryFeatures,
+      offline: offline,
     );
   }
 }

webdev/lib/src/command/shared.dart

@@ -74,7 +74,11 @@ void addSharedArgs(ArgParser argParser,
         abbr: 'v',
         defaultsTo: false,
         negatable: false,
-        help: 'Enables verbose logging.');
+        help: 'Enables verbose logging.')
+    ..addFlag(offlineFlag,
+        defaultsTo: false,
+        negatable: false,
+        help: 'Disable feching from pub.dev.');
 }
 
 /// Parses the provided [Configuration] to return a list of
@@ -103,7 +107,9 @@ List<String> buildRunnerArgs(Configuration configuration) {
 }
 
 Future<void> validatePubspecLock(Configuration configuration) async {
-  final pubspecLock = await PubspecLock.read();
+  final pubspecLock = await PubspecLock.read(
+    offline: configuration.offline
+  );
   await checkPubspecLock(pubspecLock,
       requireBuildWebCompilers: configuration.requireBuildWebCompilers);
 }

webdev/lib/src/pubspec.dart

@@ -68,8 +68,12 @@ class PubspecLock {
 
   PubspecLock(this._packages);
 
-  static Future<PubspecLock> read() async {
-    await _runPubDeps();
+  static Future<PubspecLock> read({
+    bool offline = false
+  }) async {
+    if (!offline) {
+      await _runPubDeps();
+    }
     var dir = p.absolute(p.current);
     while (true) {
       final candidate = p.join(