[eas-cli] Print the eas-cli dependency notice only when stderr is a terminal

[vonovak]

Why

When a project has eas-cli in its dependencies, eas-cli writes this notice to stderr before the command runs:

Found eas-cli in your project dependencies.
It's recommended to use the "cli.version" field in eas.json to enforce the eas-cli version for your project.
Learn more: https://github.com/expo/eas-cli#enforcing-eas-cli-version-for-your-project

The notice is advice for a person. A program that runs eas-cli reads stderr for the command's error, and it finds this notice first. In expo/expo-agent-cli, status --explain showed the notice as the reason that build:list failed.

This is the first of four stacked PRs that make eas-cli output easier for programs to read: #4591 (this PR) ← #4592 writes the failure reason to stderr ← #4593 prints a JSON error with --json ← #4594 adds error codes to it.

How

eas-cli prints the notice only when stderr is a terminal (process.stderr.isTTY is true). When stderr is a pipe or a file, eas-cli skips the notice and does not read package.json for it.

Who runs eas-cli	stderr	Notice
A person, in a terminal	terminal	printed, as before
A program that captures stderr	pipe	not printed
CI or EAS Build	usually a pipe or a file	not printed

Trade-off: CI logs and EAS Build logs no longer show the notice.

I did not use --non-interactive for this check. That flag stops prompts, but it does not tell who reads the output. A person can pass it in a terminal, and a program can run eas-cli without it.

LLM Authorship

• Vojtech asked for this change after a review of expo/expo-agent-cli found the notice quoted as an error. Claude Code wrote the change.
• An AI design review chose the TTY gate over --json or --non-interactive. An AI diff review found that the test failed when run in a terminal. The test now sets isTTY for every test in the file.

Test Plan

• New unit test: with eas-cli in devDependencies, a call without a TTY prints nothing, and a later call with a TTY prints the notice. The test fails without the fix. It passes piped and in a terminal (script -q /dev/null yarn test ...).
• Real run in a scratch project with eas-cli in devDependencies, stderr captured to a file: 24.12.1 printed the notice; this branch does not.
• tsc, oxlint and oxfmt are clean.

🤖 Generated with Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 74.48%. Comparing base (4400b93) to head (7f317ab).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4591      +/-   ##
==========================================
+ Coverage   74.46%   74.48%   +0.02%     
==========================================
  Files        1029     1029              
  Lines       50390    50390              
  Branches    10891    10891              
==========================================
+ Hits        37519    37528       +9     
+ Misses      11881    11872       -9     
  Partials      990      990              

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[github-actions]

Subscribed to pull request

File Patterns	Mentions
packages/eas-cli/**	@douglowder

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[douglowder]

eas-cli now uses changesets for changelogs (#4580). The required "Check for a changeset" check fails on PRs that edit CHANGELOG.md.

To update this PR:

1. Revert the changes to CHANGELOG.md.
2. Run yarn changeset, select the changed packages and the bump type, and write the summary.
3. Commit the new file in .changeset/.

The release adds the PR link and the author to the entry. If this PR needs no changelog entry, revert the CHANGELOG.md changes and add the "no changelog" label.

[github-actions]

✅ Thank you for adding a changeset!