Auto merge of #15896 - minestarks:run-quickpick, r=Veykril

Show placeholder while run command gets runnables from server

This PR fixes a UI annoyance in the VS Code extension when working in large codebases where rust-analyzer can take a few moments to interact with the server. Scenario:

1. Invoke "rust-analyzer: Run" from the command palette or hotkey
2. Quickly start typing to filter the list (or press Enter to accept the last runnable)

We often do this quickly from muscle memory without waiting to see the picker. The picker often takes several seconds to come up, causing us to type garbage into the currently open editor.

Fix:

Show a placeholder item before we call out to the server.

![image](https://github.com/rust-lang/rust-analyzer/assets/16928427/09de6a1c-6f3c-4d29-8031-ba4baeb43282)

Selecting this item does nothing so if the user accidentally hits Enter nothing happens.

The list is populated and the placeholder dismissed when the actual runnables are retrieved. From here the behavior is the same as before.

![image](https://github.com/rust-lang/rust-analyzer/assets/16928427/837c7dfc-c060-4d68-bbf6-df8aa3101b78)

Author: bors

editors/code/src/run.ts

@@ -7,6 +7,8 @@ import type { CtxInit } from "./ctx";
 import { makeDebugConfig } from "./debug";
 import type { Config, RunnableEnvCfg, RunnableEnvCfgItem } from "./config";
 import { unwrapUndefinable } from "./undefinable";
+import type { LanguageClient } from "vscode-languageclient/node";
+import type { RustEditor } from "./util";
 
 const quickPickButtons = [
     { iconPath: new vscode.ThemeIcon("save"), tooltip: "Save as a launch.json configuration." },
@@ -21,73 +23,36 @@ export async function selectRunnable(
     const editor = ctx.activeRustEditor;
     if (!editor) return;
 
-    const client = ctx.client;
-    const textDocument: lc.TextDocumentIdentifier = {
-        uri: editor.document.uri.toString(),
-    };
-
-    const runnables = await client.sendRequest(ra.runnables, {
-        textDocument,
-        position: client.code2ProtocolConverter.asPosition(editor.selection.active),
-    });
-    const items: RunnableQuickPick[] = [];
-    if (prevRunnable) {
-        items.push(prevRunnable);
+    // show a placeholder while we get the runnables from the server
+    const quickPick = vscode.window.createQuickPick();
+    quickPick.title = "Select Runnable";
+    if (showButtons) {
+        quickPick.buttons = quickPickButtons;
     }
-    for (const r of runnables) {
-        if (prevRunnable && JSON.stringify(prevRunnable.runnable) === JSON.stringify(r)) {
-            continue;
-        }
+    quickPick.items = [{ label: "Looking for runnables..." }];
+    quickPick.activeItems = [];
+    quickPick.show();
 
-        if (debuggeeOnly && (r.label.startsWith("doctest") || r.label.startsWith("cargo"))) {
-            continue;
-        }
-        items.push(new RunnableQuickPick(r));
-    }
+    const runnables = await getRunnables(ctx.client, editor, prevRunnable, debuggeeOnly);
 
-    if (items.length === 0) {
+    if (runnables.length === 0) {
         // it is the debug case, run always has at least 'cargo check ...'
         // see crates\rust-analyzer\src\main_loop\handlers.rs, handle_runnables
         await vscode.window.showErrorMessage("There's no debug target!");
+        quickPick.dispose();
         return;
     }
 
-    return await new Promise((resolve) => {
-        const disposables: vscode.Disposable[] = [];
-        const close = (result?: RunnableQuickPick) => {
-            resolve(result);
-            disposables.forEach((d) => d.dispose());
-        };
+    // clear the list before we hook up listeners to to avoid invoking them
+    // if the user happens to accept the placeholder item
+    quickPick.items = [];
 
-        const quickPick = vscode.window.createQuickPick<RunnableQuickPick>();
-        quickPick.items = items;
-        quickPick.title = "Select Runnable";
-        if (showButtons) {
-            quickPick.buttons = quickPickButtons;
-        }
-        disposables.push(
-            quickPick.onDidHide(() => close()),
-            quickPick.onDidAccept(() => close(quickPick.selectedItems[0])),
-            quickPick.onDidTriggerButton(async (_button) => {
-                const runnable = unwrapUndefinable(quickPick.activeItems[0]).runnable;
-                await makeDebugConfig(ctx, runnable);
-                close();
-            }),
-            quickPick.onDidChangeActive((activeList) => {
-                if (showButtons && activeList.length > 0) {
-                    const active = unwrapUndefinable(activeList[0]);
-                    if (active.label.startsWith("cargo")) {
-                        // save button makes no sense for `cargo test` or `cargo check`
-                        quickPick.buttons = [];
-                    } else if (quickPick.buttons.length === 0) {
-                        quickPick.buttons = quickPickButtons;
-                    }
-                }
-            }),
-            quickPick,
-        );
-        quickPick.show();
-    });
+    return await populateAndGetSelection(
+        quickPick as vscode.QuickPick<RunnableQuickPick>,
+        runnables,
+        ctx,
+        showButtons,
+    );
 }
 
 export class RunnableQuickPick implements vscode.QuickPickItem {
@@ -187,3 +152,75 @@ export function createArgs(runnable: ra.Runnable): string[] {
     }
     return args;
 }
+
+async function getRunnables(
+    client: LanguageClient,
+    editor: RustEditor,
+    prevRunnable?: RunnableQuickPick,
+    debuggeeOnly = false,
+): Promise<RunnableQuickPick[]> {
+    const textDocument: lc.TextDocumentIdentifier = {
+        uri: editor.document.uri.toString(),
+    };
+
+    const runnables = await client.sendRequest(ra.runnables, {
+        textDocument,
+        position: client.code2ProtocolConverter.asPosition(editor.selection.active),
+    });
+    const items: RunnableQuickPick[] = [];
+    if (prevRunnable) {
+        items.push(prevRunnable);
+    }
+    for (const r of runnables) {
+        if (prevRunnable && JSON.stringify(prevRunnable.runnable) === JSON.stringify(r)) {
+            continue;
+        }
+
+        if (debuggeeOnly && (r.label.startsWith("doctest") || r.label.startsWith("cargo"))) {
+            continue;
+        }
+        items.push(new RunnableQuickPick(r));
+    }
+
+    return items;
+}
+
+async function populateAndGetSelection(
+    quickPick: vscode.QuickPick<RunnableQuickPick>,
+    runnables: RunnableQuickPick[],
+    ctx: CtxInit,
+    showButtons: boolean,
+): Promise<RunnableQuickPick | undefined> {
+    return new Promise((resolve) => {
+        const disposables: vscode.Disposable[] = [];
+        const close = (result?: RunnableQuickPick) => {
+            resolve(result);
+            disposables.forEach((d) => d.dispose());
+        };
+        disposables.push(
+            quickPick.onDidHide(() => close()),
+            quickPick.onDidAccept(() => close(quickPick.selectedItems[0] as RunnableQuickPick)),
+            quickPick.onDidTriggerButton(async (_button) => {
+                const runnable = unwrapUndefinable(
+                    quickPick.activeItems[0] as RunnableQuickPick,
+                ).runnable;
+                await makeDebugConfig(ctx, runnable);
+                close();
+            }),
+            quickPick.onDidChangeActive((activeList) => {
+                if (showButtons && activeList.length > 0) {
+                    const active = unwrapUndefinable(activeList[0]);
+                    if (active.label.startsWith("cargo")) {
+                        // save button makes no sense for `cargo test` or `cargo check`
+                        quickPick.buttons = [];
+                    } else if (quickPick.buttons.length === 0) {
+                        quickPick.buttons = quickPickButtons;
+                    }
+                }
+            }),
+            quickPick,
+        );
+        // populate the list with the actual runnables
+        quickPick.items = runnables;
+    });
+}