src/goTest.ts: add debug previous command

The extension currently provides a "Go: Test Previous" command which
re-executes the last test that was run. To re-run the last debug session
the user can usually just use F5 to run the currently selected launch
config. However when debugging a test without a launch config (either
"Go: Debug Test at Cursor" or through the codelens), they must first
navigate back to the test to debug it.

This change adds a "Go: Debug Previous" command which allows the user
to rerun the last debug session that was executed through debugging
the test at the cursor. This does not include the debug sessions that
occur using the launch.json, since these can be re-run by using the
currently selected launch configuration.

Fixes #798

Change-Id: If44cd9b8d213a9030664a0f3ae0972e567a57f22
Reviewed-on: https://go-review.googlesource.com/c/vscode-go/+/310185
Trust: Suzy Mueller <suzmue@golang.org>
Run-TryBot: Suzy Mueller <suzmue@golang.org>
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
TryBot-Result: kokoro <noreply+kokoro@google.com>

docs/commands.md

@@ -71,6 +71,10 @@ Runs all unit tests from all packages in the current workspace.
 
 Re-runs the last executed test.
 
+### `Go: Debug Previous`
+
+Re-runs the last debugged test run through a codelens or "Go: Debug Test at Cursor" command.
+
 ### `Go: Toggle Test Coverage In Current Package`
 
 Displays test coverage in the current package.

package.json

@@ -232,6 +232,11 @@
         "title": "Go: Test Previous",
         "description": "Re-runs the last executed test."
       },
+      {
+        "command": "go.debug.previous",
+        "title": "Go: Debug Previous",
+        "description": "Re-runs the last debugged test run through a codelens or \"Go: Debug Test at Cursor\" command."
+      },
       {
         "command": "go.test.coverage",
         "title": "Go: Toggle Test Coverage In Current Package",

src/goMain.ts

@@ -64,6 +64,7 @@ import { GoReferencesCodeLensProvider } from './goReferencesCodelens';
 import { GoRunTestCodeLensProvider } from './goRunTestCodelens';
 import { disposeGoStatusBar, expandGoStatusBar, outputChannel, updateGoStatusBar } from './goStatus';
 import {
+	debugPrevious,
 	subTestAtCursor,
 	testAtCursor,
 	testCurrentFile,
@@ -375,6 +376,12 @@ If you would like additional configuration for diagnostics from gopls, please se
 		})
 	);
 
+	ctx.subscriptions.push(
+		vscode.commands.registerCommand('go.debug.previous', () => {
+			debugPrevious();
+		})
+	);
+
 	ctx.subscriptions.push(
 		vscode.commands.registerCommand('go.test.coverage', () => {
 			toggleCoverageCurrentPackage();

src/goTest.ts

@@ -24,6 +24,11 @@ import {
 // the last test to be easily re-executed.
 let lastTestConfig: TestConfig;
 
+// lastDebugConfig holds a reference to the last executed DebugConfiguration which allows
+// the last test to be easily re-executed and debugged.
+let lastDebugConfig: vscode.DebugConfiguration;
+let lastDebugWorkspaceFolder: vscode.WorkspaceFolder;
+
 export type TestAtCursorCmd = 'debug' | 'test' | 'benchmark';
 
 /**
@@ -203,6 +208,8 @@ async function debugTestAtCursor(
 		args,
 		buildFlags: buildFlags.join(' ')
 	};
+	lastDebugConfig = debugConfig;
+	lastDebugWorkspaceFolder = workspaceFolder;
 	return await vscode.debug.startDebugging(workspaceFolder, debugConfig);
 }
 
@@ -327,3 +334,14 @@ export function testPrevious() {
 		console.error(err);
 	});
 }
+
+/**
+ * Runs the previously executed test.
+ */
+export function debugPrevious() {
+	if (!lastDebugConfig) {
+		vscode.window.showInformationMessage('No test has been recently debugged.');
+		return;
+	}
+	return vscode.debug.startDebugging(lastDebugWorkspaceFolder, lastDebugConfig);
+}