debugger: Fix debug scenario's defined in debug.json not using passed in build task (#29973)

There were two bugs that caused user-defined debug scenarios from being
able to run a build task.

1. DebugRequest would be deserialized to `Attach` even when `process_id`
wasn't defined in a user's configuration file. This has been fixed by
adding our own deserializer that defaults to None if there are no fields
present instead of `Attach`, and I added tests to prevent regressions.
2. Debug scenario resolve phase never got the active buffer when
spawning a debug session from the new session modal. This has been
worked around by passing in the worktree_id of a debug scenario in the
scenario picker and the active worktree_id otherwise.

Release Notes:

- N/A

crates/debugger_ui/src/attach_modal.rs

@@ -237,7 +237,7 @@ impl PickerDelegate for AttachModalDelegate {
             .flatten();
         if let Some(panel) = panel {
             panel.update(cx, |panel, cx| {
-                panel.start_session(scenario, Default::default(), None, window, cx);
+                panel.start_session(scenario, Default::default(), None, None, window, cx);
             });
         }
 

crates/debugger_ui/src/debugger_panel.rs

@@ -22,8 +22,8 @@ use gpui::{
 };
 
 use language::Buffer;
-use project::Fs;
 use project::debugger::session::{Session, SessionStateEvent};
+use project::{Fs, WorktreeId};
 use project::{Project, debugger::session::ThreadStatus};
 use rpc::proto::{self};
 use settings::Settings;
@@ -208,6 +208,7 @@ impl DebugPanel {
         scenario: DebugScenario,
         task_context: TaskContext,
         active_buffer: Option<Entity<Buffer>>,
+        worktree_id: Option<WorktreeId>,
         window: &mut Window,
         cx: &mut Context<Self>,
     ) {
@@ -233,6 +234,7 @@ impl DebugPanel {
                                 scenario,
                                 task_context,
                                 active_buffer,
+                                worktree_id,
                                 window,
                                 cx,
                             )
@@ -1283,7 +1285,7 @@ impl workspace::DebuggerProvider for DebuggerProvider {
     ) {
         self.0.update(cx, |_, cx| {
             cx.defer_in(window, |this, window, cx| {
-                this.start_session(definition, context, buffer, window, cx);
+                this.start_session(definition, context, buffer, None, window, cx);
             })
         })
     }

crates/debugger_ui/src/new_session_modal.rs

@@ -150,6 +150,7 @@ impl NewSessionModal {
             let task_contexts = workspace
                 .update_in(cx, |this, window, cx| task_contexts(this, window, cx))?
                 .await;
+            let worktree_id = task_contexts.worktree();
             let task_context = task_contexts
                 .active_item_context
                 .map(|(_, _, context)| context)
@@ -159,8 +160,9 @@ impl NewSessionModal {
                         .map(|(_, context)| context)
                 })
                 .unwrap_or_default();
+
             debug_panel.update_in(cx, |debug_panel, window, cx| {
-                debug_panel.start_session(config, task_context, None, window, cx)
+                debug_panel.start_session(config, task_context, None, worktree_id, window, cx)
             })?;
             this.update(cx, |_, cx| {
                 cx.emit(DismissEvent);
@@ -937,19 +939,27 @@ impl PickerDelegate for DebugScenarioDelegate {
                     .await
                     .task_context_for_worktree_id(worktree_id)
                     .cloned()
+                    .map(|context| (context, Some(worktree_id)))
             })
         } else {
             gpui::Task::ready(None)
         };
 
         cx.spawn_in(window, async move |this, cx| {
-            let task_context = task_context.await.unwrap_or_default();
+            let (task_context, worktree_id) = task_context.await.unwrap_or_default();
 
             this.update_in(cx, |this, window, cx| {
                 this.delegate
                     .debug_panel
                     .update(cx, |panel, cx| {
-                        panel.start_session(debug_scenario, task_context, None, window, cx);
+                        panel.start_session(
+                            debug_scenario,
+                            task_context,
+                            None,
+                            worktree_id,
+                            window,
+                            cx,
+                        );
                     })
                     .ok();
 

crates/debugger_ui/src/session/running.rs

@@ -29,7 +29,7 @@ use language::Buffer;
 use loaded_source_list::LoadedSourceList;
 use module_list::ModuleList;
 use project::{
-    Project,
+    Project, WorktreeId,
     debugger::session::{Session, SessionEvent, ThreadId, ThreadStatus},
     terminals::TerminalKind,
 };
@@ -684,6 +684,7 @@ impl RunningState {
         scenario: DebugScenario,
         task_context: TaskContext,
         buffer: Option<Entity<Buffer>>,
+        worktree_id: Option<WorktreeId>,
         window: &Window,
         cx: &mut Context<Self>,
     ) -> Task<Result<DebugTaskDefinition>> {
@@ -712,7 +713,7 @@ impl RunningState {
                     this.task_inventory().and_then(|inventory| {
                         inventory
                             .read(cx)
-                            .task_template_by_label(buffer, &build, cx)
+                            .task_template_by_label(buffer, worktree_id, &build, cx)
                     })
                 })?
                 else {