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

.changeset/dependency-notice-tty.md

@@ -0,0 +1,5 @@
+---
+'eas-cli': patch
+---
+
+Print the notice about eas-cli in project dependencies only when stderr is a terminal, so programs that read stderr get the command's error.

packages/eas-cli/src/commandUtils/context/contextUtils/__tests__/findProjectDirAndVerifyProjectSetupAsync-test.ts

@@ -11,8 +11,16 @@ jest.mock('fs');
 
 jest.mock('../../../../prompts');
 
+const originalStderrIsTTY = process.stderr.isTTY;
+
 beforeEach(() => {
   jest.resetAllMocks();
+  // The dependency notice prints once per process and only to a terminal, so keep it unspent.
+  process.stderr.isTTY = false;
+});
+
+afterAll(() => {
+  process.stderr.isTTY = originalStderrIsTTY;
 });
 
 describe(findProjectRootAsync, () => {
@@ -115,3 +123,32 @@ describe(findProjectDirAndVerifyProjectSetupAsync, () => {
     await expect(findProjectDirAndVerifyProjectSetupAsync({ cwd: '/app' })).resolves.not.toThrow();
   });
 });
+
+describe('eas-cli dependency notice', () => {
+  beforeEach(() => {
+    vol.reset();
+    vol.fromJSON(
+      {
+        './eas.json': JSON.stringify({}),
+        './package.json': JSON.stringify({ devDependencies: { 'eas-cli': '*' } }),
+      },
+      '/app'
+    );
+  });
+
+  afterEach(() => {
+    jest.restoreAllMocks();
+  });
+
+  it('prints the notice only when stderr is a terminal', async () => {
+    const warn = jest.spyOn(console, 'warn').mockImplementation(() => {});
+
+    process.stderr.isTTY = false;
+    await findProjectDirAndVerifyProjectSetupAsync({ cwd: '/app' });
+    expect(warn).not.toHaveBeenCalled();
+
+    process.stderr.isTTY = true;
+    await findProjectDirAndVerifyProjectSetupAsync({ cwd: '/app' });
+    expect(warn).toHaveBeenCalledWith(expect.stringContaining('in your project dependencies'));
+  });
+});

packages/eas-cli/src/commandUtils/context/contextUtils/findProjectDirAndVerifyProjectSetupAsync.ts

@@ -127,7 +127,8 @@ export async function findProjectDirAndVerifyProjectSetupAsync({
 } = {}): Promise<string> {
   const projectDir = await findProjectRootAsync({ cwd });
   await applyCliConfigAsync(projectDir);
-  if (!ranEnsureEasCliIsNotInDependencies) {
+  // The notice is advice for a person. Programs that run eas-cli read stderr for its errors.
+  if (!ranEnsureEasCliIsNotInDependencies && process.stderr.isTTY) {
     ranEnsureEasCliIsNotInDependencies = true;
     await ensureEasCliIsNotInDependenciesAsync(projectDir);
   }