lerna list output is truncated at 8192 bytes when execed

[jonscheiding]

Current Behavior

When executing lerna list from within a Node process via exec or spawn, the stdout is truncated at 8192 bytes.

Expected Behavior

All stdout output should be captured.

This appears to have been introduced with bafe090, because the process.exit terminates the process handle before the output buffers are finished flushing.

Reference: https://stackoverflow.com/a/59322701/27578

Steps to Reproduce

Run this code in a monorepo which has a large enough number of packages to push the output of list past 8192 bytes.

const { exec } = require("child_process");

exec("npx lerna@8.1.2 list --all --json", (error, stdout, stderr) => {
  console.log(`stdout: ${stdout}`);
});

Other variantions tried:

const { exec } = require("child_process");

const process = exec("npx lerna@8.1.2 list --all --json");

let stdout = "";
process.stdout.on("data", (chunk) => (stdout += chunk));

process.on("close", () => {
  console.log(stdout);
});

const { spawn } = require("child_process");

const process = spawn("npx", ["lerna@8.1.2", "list", "--all", "--json"]);

let stdout = "";
process.stdout.on("data", (chunk) => (stdout += chunk));

process.on("close", () => {
  console.log(stdout);
});

These snippets work as expected with lerna@8.1.0.

[smerrill]

Here is a simple reproduction and fix using our actual lerna list --all --json output. Without the process.stdout.end() callback, test2.js would only receive 8k and not our full 20k of output.

[RoXuS]

+1 same issue during our release, hard to debug, all works as expected on 8.1.0.

This commit seems to be the culprit: bafe090