fix: reset terminal prompt on session changes

scripts/e2e-terminal-stop.test.mjs

@@ -9,6 +9,7 @@ import {
   onRunStart,
   onRunResult,
   printInfo,
+  resetTerminalSession,
   showInitialPrompt,
   startRun,
   stopRun,
@@ -20,13 +21,14 @@ function setupTerminalHarness({
   onRun,
 } = {}) {
   const writes = [];
+  const clearCalls = [];
   const runStateChanges = [];
   const runPreparationChanges = [];
   const stopCalls = [];
   const runCalls = [];
   const stdinMessages = [];
   const fakeTerm = {
-    clear() {},
+    clear() { clearCalls.push(true); },
     write(text) { writes.push(text); },
   };
 
@@ -46,6 +48,7 @@ function setupTerminalHarness({
 
   return {
     writes,
+    clearCalls,
     runStateChanges,
     runPreparationChanges,
     stopCalls,
@@ -87,6 +90,27 @@ test('e2e: initial terminal prompt is only written once', () => {
   assert.equal(output.match(/browser\.cpp/g)?.length, 1);
 });
 
+test('e2e: resetting a terminal session clears output and redraws one prompt', () => {
+  const ctx = setupTerminalHarness();
+  showInitialPrompt();
+  printInfo('stale output');
+
+  resetTerminalSession({ name: 'project', entries: [] });
+
+  assert.equal(ctx.clearCalls.length, 1);
+  assert.equal(ctx.writes.at(-1).match(/browser\.cpp/g)?.length, 1);
+  assert.match(ctx.writes.at(-1), /browser\.cpp.*:~\$ /);
+});
+
+test('e2e: resetting before compiler readiness does not print a prompt', () => {
+  const ctx = setupTerminalHarness();
+
+  resetTerminalSession();
+
+  assert.equal(ctx.clearCalls.length, 1);
+  assert.equal(ctx.writes.length, 0);
+});
+
 test('e2e: clearing during startup does not reveal the initial prompt early', () => {
   const ctx = setupTerminalHarness();
 

src/ui/terminal.js

@@ -362,6 +362,19 @@ export function clearTerminal() {
   writePrompt();
 }
 
+/**
+ * Start a clean terminal session for a workspace transition.
+ * Unlike clearTerminal(), this also resets the workspace prompt context and
+ * input line before drawing at most one prompt.
+ */
+export function resetTerminalSession(workspace = null) {
+  inputBuffer = '';
+  historyIdx = -1;
+  setWorkspace(workspace);
+  term?.clear();
+  if (initialPromptShown) writePrompt();
+}
+
 /** Write the first shell prompt after compiler startup has reached a terminal state. */
 export function showInitialPrompt() {
   if (initialPromptShown) return;

src/ui/toolbar.js

@@ -599,7 +599,6 @@ function clearTransientProjectState() {
   _runAfterSuccessfulCompile = false;
   _runPreparationActive = false;
   _lastRunBinaryBytes = null;
-  _terminalAPI.clearTerminal?.();
   _editorAPI.clearDiagnostics?.();
 }
 
@@ -608,6 +607,7 @@ export function restoreNoWorkspaceSource(source) {
   closeAllTabs();
   _fsAPI.newFile();
   clearWorkspaceMode();
+  _terminalAPI.resetTerminalSession?.(null);
   openTabForFile(UNSAVED_TAB_PATH, source);
   markDirty(false);
 }
@@ -1097,15 +1097,14 @@ function showOpenError(err) {
 function setWorkspaceMode(workspace) {
   _workspace = workspace;
   _expandedWorkspaceDirectories.clear();
-  _terminalAPI.setWorkspace?.(workspace);
+  _terminalAPI.resetTerminalSession?.(workspace);
   updateCompileButtons();
   startWorkspaceSyncPolling();
 }
 
 function clearWorkspaceMode() {
   _workspace = null;
   _expandedWorkspaceDirectories.clear();
-  _terminalAPI.setWorkspace?.(null);
   const tree = document.getElementById('file-tree');
   if (tree) tree.innerHTML = '';
   updateCompileButtons(false);