fix(bash): kept persistent shells after cancel

Stopped marking persistent bash sessions as permanently broken when the JavaScript abort or timeout race wins.

Stopped the Rust descendant kill-wave helper once no cancellation targets remain so later commands are not swept into old cancels.

Fixes #1347

crates/pi-shell/src/shell.rs

@@ -972,21 +972,22 @@ async fn read_output_bytes(
 }
 
 // Rescan-and-signal loop for cancellation. Each pass picks up descendants
-// spawned during the previous wave's grace period; empty scans keep going so a
-// cancellation that wins before `run_string` exposes its child still escalates.
+// spawned during the previous wave's grace period, then exits as soon as no
+// targets remain so unrelated later commands are not swept into old cancels.
 async fn terminate_new_descendants<S: std::hash::BuildHasher>(baseline: &HashSet<i32, S>) {
 	const WAVES: u32 = 3;
 	for wave in 0..WAVES {
 		let mut targets = process::TerminationTargets::new();
 		process::add_new_descendants(&mut targets, baseline);
-		if !targets.is_empty() {
-			let signal = if wave == 0 {
-				process::TERM_SIGNAL
-			} else {
-				process::KILL_SIGNAL
-			};
-			targets.signal(signal);
+		if targets.is_empty() {
+			return;
 		}
+		let signal = if wave == 0 {
+			process::TERM_SIGNAL
+		} else {
+			process::KILL_SIGNAL
+		};
+		targets.signal(signal);
 		if wave + 1 < WAVES {
 			let pause = if wave == 0 {
 				Duration::from_millis(75)

packages/coding-agent/src/exec/bash-executor.ts

@@ -207,9 +207,6 @@ export async function executeBash(command: string, options?: BashExecutorOptions
 			void runPromise.catch(() => undefined);
 			if (shellSession) {
 				resetSession = true;
-				// Fall back to one-shot execution for the rest of the process once
-				// a persistent session has stopped responding to cancellation.
-				brokenShellSessions.add(sessionKey);
 			}
 			return {
 				exitCode: undefined,

packages/coding-agent/test/bash-executor.test.ts

@@ -197,6 +197,20 @@ describe("executeBash", () => {
 			expect(raced.result.output).toContain("Command cancelled");
 		}
 		expect(abortSpy).toHaveBeenCalled();
+
+		vi.restoreAllMocks();
+
+		await executeBash("export PI_AFTER_ABORT=still_persistent", {
+			cwd: tempDir,
+			timeout: 5000,
+			sessionKey: "hung-native-abort",
+		});
+		const next = await executeBash("printf '%s\n' \"$PI_AFTER_ABORT\"", {
+			cwd: tempDir,
+			timeout: 5000,
+			sessionKey: "hung-native-abort",
+		});
+		expect(next.output.trim()).toBe("still_persistent");
 	});
 
 	it("returns at the JavaScript timeout when native timeout cleanup stalls", async () => {