debugger: Allow users to include PickProcessId in debug tasks and resolve Pid (#42913)

Closes #33286

This PR adds support for Zed's `$ZED_PICK_PID` command in debug
configurations, which allows users to select a process to attach to at
debug time. When this variable is present in a debug configuration, Zed
automatically opens a process picker modal.

Follow up for this will be integrating this variable in the task system
instead of just the debug configuration system.

Release Notes:

- Added `$ZED_PICK_PID` variable for debug configurations, allowing
users to select which process to attach the debugger to at runtime

---------

Co-authored-by: Remco Smits <djsmits12@gmail.com>

crates/debugger_ui/src/tests/attach_modal.rs

@@ -1,4 +1,8 @@
-use crate::{attach_modal::Candidate, tests::start_debug_session_with, *};
+use crate::{
+    attach_modal::{Candidate, ModalIntent},
+    tests::start_debug_session_with,
+    *,
+};
 use attach_modal::AttachModal;
 use dap::{FakeAdapter, adapters::DebugTaskDefinition};
 use gpui::{BackgroundExecutor, TestAppContext, VisualTestContext};
@@ -98,12 +102,6 @@ async fn test_show_attach_modal_and_select_process(
             workspace.toggle_modal(window, cx, |window, cx| {
                 AttachModal::with_processes(
                     workspace_handle,
-                    task::ZedDebugConfig {
-                        adapter: FakeAdapter::ADAPTER_NAME.into(),
-                        request: dap::DebugRequest::Attach(AttachRequest::default()),
-                        label: "attach example".into(),
-                        stop_on_entry: None,
-                    },
                     vec![
                         Candidate {
                             pid: 0,
@@ -124,6 +122,12 @@ async fn test_show_attach_modal_and_select_process(
                     .into_iter()
                     .collect(),
                     true,
+                    ModalIntent::AttachToProcess(task::ZedDebugConfig {
+                        adapter: FakeAdapter::ADAPTER_NAME.into(),
+                        request: dap::DebugRequest::Attach(AttachRequest::default()),
+                        label: "attach example".into(),
+                        stop_on_entry: None,
+                    }),
                     window,
                     cx,
                 )
@@ -138,8 +142,7 @@ async fn test_show_attach_modal_and_select_process(
     // assert we got the expected processes
     workspace
         .update(cx, |_, window, cx| {
-            let names =
-                attach_modal.update(cx, |modal, cx| attach_modal::_process_names(modal, cx));
+            let names = attach_modal.update(cx, |modal, cx| attach_modal::process_names(modal, cx));
             // Initially all processes are visible.
             assert_eq!(3, names.len());
             attach_modal.update(cx, |this, cx| {
@@ -153,8 +156,7 @@ async fn test_show_attach_modal_and_select_process(
     // assert we got the expected processes
     workspace
         .update(cx, |_, _, cx| {
-            let names =
-                attach_modal.update(cx, |modal, cx| attach_modal::_process_names(modal, cx));
+            let names = attach_modal.update(cx, |modal, cx| attach_modal::process_names(modal, cx));
             // Initially all processes are visible.
             assert_eq!(2, names.len());
         })
@@ -171,3 +173,139 @@ async fn test_show_attach_modal_and_select_process(
         })
         .unwrap();
 }
+
+#[gpui::test]
+async fn test_attach_with_pick_pid_variable(executor: BackgroundExecutor, cx: &mut TestAppContext) {
+    init_test(cx);
+
+    let fs = FakeFs::new(executor.clone());
+
+    fs.insert_tree(
+        path!("/project"),
+        json!({
+            "main.rs": "First line\nSecond line\nThird line\nFourth line",
+        }),
+    )
+    .await;
+
+    let project = Project::test(fs, [path!("/project").as_ref()], cx).await;
+    let workspace = init_test_workspace(&project, cx).await;
+    let cx = &mut VisualTestContext::from_window(*workspace, cx);
+
+    let _initialize_subscription =
+        project::debugger::test::intercept_debug_sessions(cx, |client| {
+            client.on_request::<dap::requests::Attach, _>(move |_, args| {
+                let raw = &args.raw;
+                assert_eq!(raw["request"], "attach");
+                assert_eq!(
+                    raw["process_id"], "42",
+                    "verify process id has been replaced"
+                );
+
+                Ok(())
+            });
+        });
+
+    let pick_pid_placeholder = task::VariableName::PickProcessId.template_value();
+    workspace
+        .update(cx, |workspace, window, cx| {
+            workspace.start_debug_session(
+                DebugTaskDefinition {
+                    adapter: FakeAdapter::ADAPTER_NAME.into(),
+                    label: "attach with picker".into(),
+                    config: json!({
+                        "request": "attach",
+                        "process_id": pick_pid_placeholder,
+                    }),
+                    tcp_connection: None,
+                }
+                .to_scenario(),
+                task::TaskContext::default(),
+                None,
+                None,
+                window,
+                cx,
+            )
+        })
+        .unwrap();
+
+    cx.run_until_parked();
+
+    let attach_modal = workspace
+        .update(cx, |workspace, _window, cx| {
+            workspace.active_modal::<AttachModal>(cx)
+        })
+        .unwrap();
+
+    assert!(
+        attach_modal.is_some(),
+        "Attach modal should open when config contains ZED_PICK_PID"
+    );
+
+    let attach_modal = attach_modal.unwrap();
+
+    workspace
+        .update(cx, |_, window, cx| {
+            attach_modal.update(cx, |modal, cx| {
+                attach_modal::set_candidates(
+                    modal,
+                    vec![
+                        Candidate {
+                            pid: 10,
+                            name: "process-1".into(),
+                            command: vec![],
+                        },
+                        Candidate {
+                            pid: 42,
+                            name: "target-process".into(),
+                            command: vec![],
+                        },
+                        Candidate {
+                            pid: 99,
+                            name: "process-3".into(),
+                            command: vec![],
+                        },
+                    ]
+                    .into_iter()
+                    .collect(),
+                    window,
+                    cx,
+                )
+            })
+        })
+        .unwrap();
+
+    cx.run_until_parked();
+
+    workspace
+        .update(cx, |_, window, cx| {
+            attach_modal.update(cx, |modal, cx| {
+                modal.picker.update(cx, |picker, cx| {
+                    picker.set_query("target", window, cx);
+                })
+            })
+        })
+        .unwrap();
+
+    cx.run_until_parked();
+
+    workspace
+        .update(cx, |_, _, cx| {
+            let names = attach_modal.update(cx, |modal, cx| attach_modal::process_names(modal, cx));
+            assert_eq!(names.len(), 1);
+            assert_eq!(names[0], " 42 target-process");
+        })
+        .unwrap();
+
+    cx.dispatch_action(Confirm);
+    cx.run_until_parked();
+
+    workspace
+        .update(cx, |workspace, _window, cx| {
+            assert!(
+                workspace.active_modal::<AttachModal>(cx).is_none(),
+                "Attach modal should be dismissed after selection"
+            );
+        })
+        .unwrap();
+}