debugger: Fix the JavaScript debug terminal scenario (#33924)

There were a couple of things preventing this from working:

- our hack to stop the node REPL from appearing broke in recent versions
of the JS DAP that started passing `--experimental-network-inspection`
by default
- we had lost the ability to create a debug terminal without specifying
a program

This PR fixes those issues. We also fixed environment variables from the
**runInTerminal** request not getting passed to the spawned program.

Release Notes:

- Debugger: Fix RunInTerminal not working for JavaScript debugger.

---------

Co-authored-by: Cole Miller <cole@zed.dev>

crates/task/src/shell_builder.rs

@@ -149,17 +149,23 @@ impl ShellBuilder {
         }
     }
     /// Returns the program and arguments to run this task in a shell.
-    pub fn build(mut self, task_command: String, task_args: &Vec<String>) -> (String, Vec<String>) {
-        let combined_command = task_args
-            .into_iter()
-            .fold(task_command, |mut command, arg| {
-                command.push(' ');
-                command.push_str(&self.kind.to_shell_variable(arg));
-                command
-            });
+    pub fn build(
+        mut self,
+        task_command: Option<String>,
+        task_args: &Vec<String>,
+    ) -> (String, Vec<String>) {
+        if let Some(task_command) = task_command {
+            let combined_command = task_args
+                .into_iter()
+                .fold(task_command, |mut command, arg| {
+                    command.push(' ');
+                    command.push_str(&self.kind.to_shell_variable(arg));
+                    command
+                });
 
-        self.args
-            .extend(self.kind.args_for_shell(self.interactive, combined_command));
+            self.args
+                .extend(self.kind.args_for_shell(self.interactive, combined_command));
+        }
 
         (self.program, self.args)
     }

crates/task/src/task.rs

@@ -46,7 +46,7 @@ pub struct SpawnInTerminal {
     /// Human readable name of the terminal tab.
     pub label: String,
     /// Executable command to spawn.
-    pub command: String,
+    pub command: Option<String>,
     /// Arguments to the command, potentially unsubstituted,
     /// to let the shell that spawns the command to do the substitution, if needed.
     pub args: Vec<String>,

crates/task/src/task_template.rs

@@ -255,7 +255,7 @@ impl TaskTemplate {
                         command_label
                     },
                 ),
-                command,
+                command: Some(command),
                 args: self.args.clone(),
                 env,
                 use_new_terminal: self.use_new_terminal,
@@ -635,7 +635,7 @@ mod tests {
                 "Human-readable label should have long substitutions trimmed"
             );
             assert_eq!(
-                spawn_in_terminal.command,
+                spawn_in_terminal.command.clone().unwrap(),
                 format!("echo test_file {long_value}"),
                 "Command should be substituted with variables and those should not be shortened"
             );
@@ -652,7 +652,7 @@ mod tests {
                 spawn_in_terminal.command_label,
                 format!(
                     "{} arg1 test_selected_text arg2 5678 arg3 {long_value}",
-                    spawn_in_terminal.command
+                    spawn_in_terminal.command.clone().unwrap()
                 ),
                 "Command label args should be substituted with variables and those should not be shortened"
             );
@@ -711,7 +711,7 @@ mod tests {
         assert_substituted_variables(&resolved_task, Vec::new());
         let resolved = resolved_task.resolved;
         assert_eq!(resolved.label, task.label);
-        assert_eq!(resolved.command, task.command);
+        assert_eq!(resolved.command, Some(task.command));
         assert_eq!(resolved.args, task.args);
     }