Trace logs interfere with output when CI=true environment variable is set

[konard]

Problem Description

When the CI environment variable is set to true (as in GitHub Actions and other CI/CD platforms), command-stream emits verbose trace logs to stderr that interfere with command output and break JSON parsing.

Reproduction Steps

1. Create a simple script using command-stream:

#!/usr/bin/env node
if (typeof use === 'undefined') {
  globalThis.use = (await eval(await (await fetch('https://unpkg.com/use-m/use.js')).text())).use;
}
const { $ } = await use('command-stream');
const $silent = $({ mirror: false, capture: true });

const result = await $silent`echo '{"status":"ok"}'`;
console.log(result.stdout || result);

2. Run without CI environment:

$ node script.js
{"status":"ok"}

3. Run with CI environment:

$ CI=true node script.js
[TRACE 2025-09-14T13:25:23.048Z] [Initialization] Registering built-in virtual commands
[TRACE 2025-09-14T13:25:23.048Z] [VirtualCommands] registerBuiltins() called
[TRACE 2025-09-14T13:25:23.050Z] [ProcessRunner] Executing virtual command
{"status":"ok"}
[TRACE 2025-09-14T13:25:23.051Z] [ProcessRunner] Cleanup completed

Impact

• Breaks JSON parsing: Output contains trace logs mixed with JSON
• Test failures in CI: Tests that parse command output fail in GitHub Actions
• Affects all CI platforms: GitHub Actions, GitLab CI, CircleCI, Jenkins

Current Behavior

Even with mirror: false and capture: true, trace logs are emitted to stderr when CI=true.

Expected Behavior

When mirror: false is set, no trace logs should be emitted, regardless of CI environment variable.

Suggested Solutions

1. Add trace option:

const $silent = $({ mirror: false, capture: true, trace: false });

2. Respect mirror:false for all output including trace logs

3. Environment variable override:

// Allow disabling via env var
process.env.COMMAND_STREAM_TRACE = 'false';

Workarounds

Currently we have to:

• Redirect stderr to /dev/null (loses legitimate errors)
• Filter trace logs from output (fragile)
• Modify test frameworks to ignore stderr in CI

Environment

• Node.js: 20.x
• command-stream: latest
• OS: Ubuntu (GitHub Actions), macOS (local)
• CI platforms: GitHub Actions, GitLab CI

Additional Context

This issue affects production CI/CD pipelines where JSON output from commands is parsed for automation. The trace logs make command-stream difficult to use reliably in CI environments.

Example of trace log components that emit logs:

• [Initialization]
• [VirtualCommands]
• [API]
• [ProcessRunner]
• [StreamMonitor]
• [SignalHandler]
• [StreamEmitter]
• [AnsiUtils]
• [Utils]

Thank you for considering this issue. command-stream is a great library, and fixing this would make it much more CI-friendly!