Take 2 on "Some initial work for FlutterWeb apps" change

src/io/flutter/run/LaunchState.java

@@ -45,6 +45,7 @@
 import io.flutter.dart.DartPlugin;
 import io.flutter.logging.FlutterLog;
 import io.flutter.logging.FlutterLogView;
+import io.flutter.pub.PubRoot;
 import io.flutter.run.bazel.BazelRunConfig;
 import io.flutter.run.daemon.*;
 import org.jetbrains.annotations.NotNull;
@@ -120,9 +121,21 @@ protected RunContentDescriptor launch(@NotNull ExecutionEnvironment env) throws
     final Project project = getEnvironment().getProject();
     final FlutterDevice device = DeviceService.getInstance(project).getSelectedDevice();
 
+    // Flutter web does not yet support device objects yet, hence the null as the indicator that this might be a flutter web project.
     if (device == null) {
-      showNoDeviceConnectedMessage(project);
-      return null;
+      boolean isFlutterWeb = false;
+      final String filePath = ((SdkRunConfig)runConfig).getFields().getFilePath();
+      if (filePath != null) {
+        final MainFile main = MainFile.verify(filePath, project).get();
+        final PubRoot root = PubRoot.forDirectory(main.getAppDir());
+        if (root != null) {
+          isFlutterWeb = FlutterUtils.declaresFlutterWeb(root.getPubspec());
+        }
+      }
+      if (!isFlutterWeb) {
+        showNoDeviceConnectedMessage(project);
+        return null;
+      }
     }
     final FlutterApp app = myCreateAppCallback.createApp(device);
 
@@ -147,7 +160,9 @@ protected RunContentDescriptor launch(@NotNull ExecutionEnvironment env) throws
       }
     }
 
-    device.bringToFront();
+    if (device != null) {
+      device.bringToFront();
+    }
 
     // Check for and display any analysis errors when we launch an app.
     if (env.getRunProfile() instanceof SdkRunConfig) {

src/io/flutter/run/SdkFields.java

@@ -14,6 +14,7 @@
 import com.jetbrains.lang.dart.sdk.DartConfigurable;
 import com.jetbrains.lang.dart.sdk.DartSdk;
 import io.flutter.FlutterBundle;
+import io.flutter.FlutterUtils;
 import io.flutter.dart.DartPlugin;
 import io.flutter.pub.PubRoot;
 import io.flutter.run.daemon.FlutterDevice;
@@ -124,11 +125,13 @@ public GeneralCommandLine createFlutterSdkRunCommand(@NotNull Project project,
       throw new ExecutionException("Entrypoint isn't within a Flutter pub root");
     }
 
-    String[] args = additionalArgs == null ? new String[]{} : additionalArgs.split(" ");
+    String[] args = additionalArgs == null ? new String[]{ } : additionalArgs.split(" ");
     if (buildFlavor != null) {
       args = ArrayUtil.append(args, "--flavor=" + buildFlavor);
     }
-    final FlutterCommand command = flutterSdk.flutterRun(root, main.getFile(), device, runMode, flutterLaunchMode, project, args);
+    final FlutterCommand command = FlutterUtils.declaresFlutterWeb(root.getPubspec()) ?
+                                   flutterSdk.flutterRunWeb(root, runMode) :
+                                   flutterSdk.flutterRun(root, main.getFile(), device, runMode, flutterLaunchMode, project, args);
     return command.createGeneralCommandLine(project);
   }
 
@@ -150,7 +153,7 @@ public GeneralCommandLine createFlutterSdkAttachCommand(@NotNull Project project
       throw new ExecutionException("Entrypoint isn't within a Flutter pub root");
     }
 
-    String[] args = additionalArgs == null ? new String[]{} : additionalArgs.split(" ");
+    String[] args = additionalArgs == null ? new String[]{ } : additionalArgs.split(" ");
     if (buildFlavor != null) {
       args = ArrayUtil.append(args, "--flavor=" + buildFlavor);
     }

src/io/flutter/run/SdkRunConfig.java

@@ -142,7 +142,8 @@ public LaunchState getState(@NotNull Executor executor, @NotNull ExecutionEnviro
     final RunMode mode = RunMode.fromEnv(env);
     final Module module = ModuleUtilCore.findModuleForFile(mainFile.getFile(), env.getProject());
     final LaunchState.CreateAppCallback createAppCallback = (device) -> {
-      if (device == null) return null;
+      // Up until the FlutterWeb support, device was checked for null and returned.  The device
+      // can only be null if this is a FlutterWeb execution, this expecation is checked elsewhere.
 
       final GeneralCommandLine command = getCommand(env, device);
       {

src/io/flutter/run/daemon/FlutterApp.java

@@ -68,7 +68,8 @@ public class FlutterApp {
   private final @NotNull Project myProject;
   private final @Nullable Module myModule;
   private final @NotNull RunMode myMode;
-  private final @NotNull FlutterDevice myDevice;
+  // TODO(github.com/flutter/flutter-intellij/issues/3293) myDevice is not-null for all run configurations except flutter web configurations
+  private final @Nullable FlutterDevice myDevice;
   private final @NotNull ProcessHandler myProcessHandler;
   private final @NotNull ExecutionEnvironment myExecutionEnvironment;
   private final @NotNull DaemonApi myDaemonApi;
@@ -122,7 +123,7 @@ public static FlutterApp fromEnv(@NotNull ExecutionEnvironment env) {
   FlutterApp(@NotNull Project project,
              @Nullable Module module,
              @NotNull RunMode mode,
-             @NotNull FlutterDevice device,
+             @Nullable FlutterDevice device,
              @NotNull ProcessHandler processHandler,
              @NotNull ExecutionEnvironment executionEnvironment,
              @NotNull DaemonApi daemonApi,
@@ -237,7 +238,7 @@ public static FlutterApp start(@NotNull ExecutionEnvironment env,
                                  @NotNull Project project,
                                  @Nullable Module module,
                                  @NotNull RunMode mode,
-                                 @NotNull FlutterDevice device,
+                                 @Nullable FlutterDevice device,
                                  @NotNull GeneralCommandLine command,
                                  @Nullable String analyticsStart,
                                  @Nullable String analyticsStop)
@@ -593,7 +594,12 @@ public FlutterDevice device() {
   }
 
   public String deviceId() {
-    return myDevice.deviceId();
+    return myDevice != null ? myDevice.deviceId() : "";
+  }
+
+  // TODO this should be a temporary hack until there is some mocked out "browser" device
+  public boolean isWebDev() {
+    return myDevice == null;
   }
 
   public void setFlutterDebugProcess(FlutterDebugProcess flutterDebugProcess) {

src/io/flutter/sdk/FlutterCommand.java

@@ -48,13 +48,28 @@ public class FlutterCommand {
   @NotNull
   private final List<String> args;
 
+  // TODO(https://github.com/flutter/flutter-intellij/issues/3348) This is a temporary "<pub-cache>/bin/webdev" that can be provided to test
+  //  some webdev directly.
+  @Nullable
+  private final String localWebDevExe = "webdev";
+
+  private final boolean isFlutterWeb;
+
   /**
    * @see FlutterSdk for methods to create specific commands.
    */
   FlutterCommand(@NotNull FlutterSdk sdk, @Nullable VirtualFile workDir, @NotNull Type type, String... args) {
+    this(sdk, workDir, type, false, args);
+  }
+
+  /**
+   * @see FlutterSdk for methods to create specific commands.
+   */
+  FlutterCommand(@NotNull FlutterSdk sdk, @Nullable VirtualFile workDir, @NotNull Type type, boolean isFlutterWeb, String... args) {
     this.sdk = sdk;
     this.workDir = workDir;
     this.type = type;
+    this.isFlutterWeb = isFlutterWeb;
     this.args = ImmutableList.copyOf(args);
   }
 
@@ -245,23 +260,54 @@ public OSProcessHandler startProcessOrShowError(@Nullable Project project) {
   public GeneralCommandLine createGeneralCommandLine(@Nullable Project project) {
     final GeneralCommandLine line = new GeneralCommandLine();
     line.setCharset(CharsetToolkit.UTF8_CHARSET);
-
-    line.withEnvironment(FlutterSdkUtil.FLUTTER_HOST_ENV, FlutterSdkUtil.getFlutterHostEnvValue());
-
-    final String androidHome = IntelliJAndroidSdk.chooseAndroidHome(project, false);
-    if (androidHome != null) {
-      line.withEnvironment("ANDROID_HOME", androidHome);
+    if (isFlutterWeb) {
+      if (workDir != null) {
+        line.setWorkDirectory(workDir.getPath());
+      }
+      if (localWebDevExe != null || !localWebDevExe.isEmpty()) {
+        line.setExePath(localWebDevExe);
+        line.addParameters("daemon");
+        if (args.contains("--debug")) {
+          line.addParameters("--debug");
+        }
+        if (args.contains("--hot-reload")) {
+          line.addParameters("--hot-reload");
+        }
+      }
+      else {
+        line.setExePath(FileUtil.toSystemDependentName(sdk.getHomePath() + "/bin/" + FlutterSdkUtil.flutterScriptName()));
+        line.addParameters(args);
+      }
     }
+    else {
+      line.withEnvironment(FlutterSdkUtil.FLUTTER_HOST_ENV, FlutterSdkUtil.getFlutterHostEnvValue());
+      final String androidHome = IntelliJAndroidSdk.chooseAndroidHome(project, false);
+      if (androidHome != null) {
+        line.withEnvironment("ANDROID_HOME", androidHome);
+      }
+      line.setExePath(FileUtil.toSystemDependentName(sdk.getHomePath() + "/bin/" + FlutterSdkUtil.flutterScriptName()));
+      if (workDir != null) {
+        line.setWorkDirectory(workDir.getPath());
+      }
+      if (!isDoctorCommand()) {
+        line.addParameter("--no-color");
+      }
+      line.addParameters(type.subCommand);
+      line.addParameters(args);
+    }
+    return line;
+  }
 
-    line.setExePath(FileUtil.toSystemDependentName(sdk.getHomePath() + "/bin/" + FlutterSdkUtil.flutterScriptName()));
+  @NotNull
+  public GeneralCommandLine createFlutterWebCommandLine(@Nullable Project project) {
+    final GeneralCommandLine line = new GeneralCommandLine();
+    line.setCharset(CharsetToolkit.UTF8_CHARSET);
     if (workDir != null) {
       line.setWorkDirectory(workDir.getPath());
     }
-    if (!isDoctorCommand()) {
-      line.addParameter("--no-color");
-    }
     line.addParameters(type.subCommand);
     line.addParameters(args);
+
     return line;
   }
 

src/io/flutter/sdk/FlutterSdk.java

@@ -269,6 +269,19 @@ else if (flutterLaunchMode == FlutterLaunchMode.RELEASE) {
     return new FlutterCommand(this, root.getRoot(), FlutterCommand.Type.ATTACH, args.toArray(new String[]{ }));
   }
 
+  public FlutterCommand flutterRunWeb(@NotNull PubRoot root, @NotNull RunMode mode) {
+    // flutter packages pub global run webdev serve [--debug] [--hot-reload]
+    final List<String> args = new ArrayList<>();
+    args.add("global");
+    args.add("run");
+    args.add("webdev");
+    args.add("daemon");
+    // TODO(https://github.com/flutter/flutter-intellij/issues/3349) After debug is supported by webdev, this should be modified to check
+    //  for debug and add any additional needed flags:
+    //  i.e. if (mode == RunMode.DEBUG) { args.add("--debug"); }
+    return new FlutterCommand(this, root.getRoot(), FlutterCommand.Type.PACKAGES_PUB, true, args.toArray(new String[]{ }));
+  }
+
   public FlutterCommand flutterRunOnTester(@NotNull PubRoot root, @NotNull String mainPath) {
     final List<String> args = new ArrayList<>();
     args.add("--machine");

src/io/flutter/server/vmService/DartVmServiceDebugProcess.java

@@ -40,6 +40,7 @@
 import gnu.trove.TIntObjectHashMap;
 import io.flutter.FlutterBundle;
 import io.flutter.FlutterUtils;
+import io.flutter.run.FlutterDebugProcess;
 import io.flutter.run.FlutterLaunchMode;
 import io.flutter.server.vmService.frame.DartVmServiceEvaluator;
 import io.flutter.server.vmService.frame.DartVmServiceStackFrame;
@@ -262,17 +263,21 @@ public void scheduleConnect() {
       // because "flutter run" has already connected to it.
       final VmService vmService;
       final VmOpenSourceLocationListener vmOpenSourceLocationListener;
-      try {
-        vmService = VmService.connect(url);
-        vmOpenSourceLocationListener = VmOpenSourceLocationListener.connect(url);
-      }
-      catch (IOException | RuntimeException e) {
-        onConnectFailed("Failed to connect to the VM observatory service at: " + url + "\n"
-                        + e.toString() + "\n" +
-                        formatStackTraces(e));
-        return;
+      // TODO(github.com/dart-lang/webdev/issues/233) The following check disables the WebSocket connection for all FlutterWeb run
+      //  configurations, for some reason the WebSocket port can't be connected to, see listed issue above.
+      if (this instanceof FlutterDebugProcess && (!((FlutterDebugProcess)this).getApp().isWebDev())) {
+        try {
+          vmService = VmService.connect(url);
+          vmOpenSourceLocationListener = VmOpenSourceLocationListener.connect(url);
+        }
+        catch (IOException | RuntimeException e) {
+          onConnectFailed("Failed to connect to the VM observatory service at: " + url + "\n"
+                          + e.toString() + "\n" +
+                          formatStackTraces(e));
+          return;
+        }
+        onConnectSucceeded(vmService, vmOpenSourceLocationListener);
       }
-      onConnectSucceeded(vmService, vmOpenSourceLocationListener);
     });
   }
 
@@ -391,7 +396,7 @@ public void runToPosition(@NotNull XSourcePosition position, @Nullable XSuspendC
 
   public void isolateSuspended(@NotNull final IsolateRef isolateRef) {
     final String id = isolateRef.getId();
-    assert(!mySuspendedIsolateIds.containsKey(id));
+    assert (!mySuspendedIsolateIds.containsKey(id));
     if (!mySuspendedIsolateIds.containsKey(id)) {
       mySuspendedIsolateIds.put(id, new CompletableFuture<>());
     }
@@ -406,10 +411,10 @@ public CompletableFuture<?> whenIsolateResumed(String isolateId) {
     if (future == null) {
       // Isolate wasn't actually suspended.
       return CompletableFuture.completedFuture(null);
-    } else {
+    }
+    else {
       return future;
     }
-
   }
 
   public boolean isIsolateAlive(@NotNull final String isolateId) {