fix: bound Web UX review evidence and cleanup

tools/web-ux/tests/lifecycle_test.ts

@@ -6,7 +6,11 @@ import {
   safeUrl,
   writePrivateJson,
 } from "../src/artifacts.ts";
-import { startOwnedProcesses, stopOwnedProcesses } from "../src/processes.ts";
+import {
+  PROCESS_LOG_BYTE_LIMIT,
+  startOwnedProcesses,
+  stopOwnedProcesses,
+} from "../src/processes.ts";
 
 Deno.test("redaction removes common credentials and query values", () => {
   const redacted = redactText(
@@ -69,6 +73,99 @@ Deno.test("owned process is terminated and its logs are redacted", async () => {
     const log = await Deno.readTextFile(logPath);
     assertEquals(log.includes("secret-value"), false);
     assertStringIncludes(log, "[REDACTED]");
+    const metadata = JSON.parse(await Deno.readTextFile(`${logPath}.meta.json`));
+    assertEquals(metadata.truncated, false);
+  } finally {
+    await Deno.remove(directory, { recursive: true });
+  }
+});
+
+Deno.test("owned process logs stop at the byte limit and record truncation", async () => {
+  const directory = await Deno.makeTempDir();
+  const scenario = join(directory, "scenario.json");
+  await Deno.writeTextFile(scenario, "{}");
+  try {
+    const processes = await startOwnedProcesses(
+      [{
+        id: "large-output",
+        command: Deno.execPath(),
+        args: [
+          "eval",
+          `console.log("x".repeat(${
+            PROCESS_LOG_BYTE_LIMIT + 32_768
+          })); setInterval(() => {}, 1000)`,
+        ],
+      }],
+      scenario,
+      join(directory, "logs"),
+      [],
+    );
+    const logPath = join(directory, "logs", "large-output.stdout.log");
+    for (let attempt = 0; attempt < 100; attempt++) {
+      try {
+        if ((await Deno.stat(logPath)).size >= PROCESS_LOG_BYTE_LIMIT) break;
+      } catch {
+        // The output pump creates the file asynchronously.
+      }
+      await new Promise((resolve) => setTimeout(resolve, 10));
+    }
+    assertEquals(await stopOwnedProcesses(processes), []);
+    assertEquals((await Deno.stat(logPath)).size, PROCESS_LOG_BYTE_LIMIT);
+    const metadata = JSON.parse(await Deno.readTextFile(`${logPath}.meta.json`));
+    assertEquals(metadata.byteLimit, PROCESS_LOG_BYTE_LIMIT);
+    assertEquals(metadata.truncated, true);
+    assertEquals(metadata.bytesWritten, PROCESS_LOG_BYTE_LIMIT);
+  } finally {
+    await Deno.remove(directory, { recursive: true });
+  }
+});
+
+Deno.test("forced cleanup terminates a TERM-resistant descendant", async () => {
+  if (Deno.build.os === "windows") return;
+  const directory = await Deno.makeTempDir();
+  const scenario = join(directory, "scenario.json");
+  const childPidPath = join(directory, "child.pid");
+  await Deno.writeTextFile(scenario, "{}");
+  try {
+    const childProgram = 'Deno.addSignalListener("SIGTERM", () => {}); setInterval(() => {}, 1000)';
+    const parentProgram = `
+      const child = new Deno.Command(Deno.execPath(), {
+        args: ["eval", ${JSON.stringify(childProgram)}],
+        stdout: "null",
+        stderr: "null"
+      }).spawn();
+      Deno.writeTextFileSync(Deno.args[0], String(child.pid));
+      Deno.addSignalListener("SIGTERM", () => {});
+      setInterval(() => {}, 1000);
+    `;
+    const processes = await startOwnedProcesses(
+      [{
+        id: "process-tree",
+        command: Deno.execPath(),
+        args: ["eval", parentProgram, childPidPath],
+      }],
+      scenario,
+      join(directory, "logs"),
+      [],
+    );
+    let childPid = 0;
+    for (let attempt = 0; attempt < 100; attempt++) {
+      try {
+        childPid = Number(await Deno.readTextFile(childPidPath));
+        if (childPid > 0) break;
+      } catch {
+        // The fixture publishes its descendant PID after spawn.
+      }
+      await new Promise((resolve) => setTimeout(resolve, 10));
+    }
+    assertEquals(childPid > 0, true);
+    assertEquals(await stopOwnedProcesses(processes), []);
+    const status = await new Deno.Command("ps", {
+      args: ["-p", String(childPid), "-o", "pid="],
+      stdout: "piped",
+      stderr: "null",
+    }).output();
+    assertEquals(new TextDecoder().decode(status.stdout).trim(), "");
   } finally {
     await Deno.remove(directory, { recursive: true });
   }