fix(coding-agent): recompute interactive bash preview width closes #2569

packages/coding-agent/test/bash-execution-width.test.ts

@@ -0,0 +1,80 @@
+/**
+ * Test that BashExecutionComponent's collapsed output respects the render-time width,
+ * not a stale captured width. Regression test for #2569.
+ */
+import { visibleWidth } from "@mariozechner/pi-tui";
+import { beforeAll, describe, expect, it } from "vitest";
+import { BashExecutionComponent } from "../src/modes/interactive/components/bash-execution.js";
+import { initTheme } from "../src/modes/interactive/theme/theme.js";
+
+/** Minimal TUI stub that only exposes terminal.columns */
+function createTuiStub(columns: number): { columns: number; stub: any } {
+	const state = { columns };
+	const stub = {
+		terminal: {
+			get columns() {
+				return state.columns;
+			},
+			get rows() {
+				return 24;
+			},
+		},
+		// Loader calls ui.addInterval / ui.removeInterval
+		addInterval: (_cb: () => void, _ms: number) => ({ dispose: () => {} }),
+		removeInterval: () => {},
+		requestRender: () => {},
+	};
+	return { columns: state.columns, stub };
+}
+
+describe("BashExecutionComponent width handling (#2569)", () => {
+	beforeAll(() => {
+		initTheme(undefined, false);
+	});
+
+	it("collapsed preview lines respect render-time width, not construction-time width", () => {
+		const wideWidth = 200;
+		const narrowWidth = 80;
+
+		const { stub } = createTuiStub(wideWidth);
+		const component = new BashExecutionComponent("pwd", stub);
+
+		// Add output with long lines that will wrap differently at different widths
+		const longLine = "x".repeat(150);
+		component.appendOutput(`${longLine}\n${longLine}\n`);
+
+		// Complete the command so it enters collapsed mode
+		component.setComplete(0, false);
+
+		// Render at the narrow width (simulating a resize or split pane)
+		const lines = component.render(narrowWidth);
+
+		// Every rendered line must fit within the narrow width
+		for (let i = 0; i < lines.length; i++) {
+			const w = visibleWidth(lines[i]);
+			expect(w, `Line ${i} visibleWidth=${w} > ${narrowWidth}`).toBeLessThanOrEqual(narrowWidth);
+		}
+	});
+
+	it("re-computes lines when width changes between renders", () => {
+		const { stub } = createTuiStub(200);
+		const component = new BashExecutionComponent("echo hello", stub);
+
+		const longLine = "abcdefghij".repeat(20); // 200 chars
+		component.appendOutput(`${longLine}\n`);
+		component.setComplete(0, false);
+
+		// First render at width 200
+		const lines200 = component.render(200);
+		for (const line of lines200) {
+			expect(visibleWidth(line)).toBeLessThanOrEqual(200);
+		}
+
+		// Second render at width 60 (split pane scenario)
+		const lines60 = component.render(60);
+		for (let i = 0; i < lines60.length; i++) {
+			const w = visibleWidth(lines60[i]);
+			expect(w, `Line ${i} visibleWidth=${w} > 60`).toBeLessThanOrEqual(60);
+		}
+	});
+});