fix: only allocate TTY when both stdin and stdout are terminals

CHANGELOG.md

@@ -1,5 +1,7 @@
 ## {{ UNRELEASED_VERSION }} - [{{ UNRELEASED_DATE }}]({{ UNRELEASED_LINK }})
 
+* Fixed ANSI escape codes appearing in redirected output by checking `stdout.isTTY` instead of `stdin.isTTY` for TTY allocation [#345](https://github.com/lando/core/issues/345)
+
 ## v3.26.2 - [December 17, 2025](https://github.com/lando/core/releases/tag/v3.26.2)
 
 * Updated to use new Lando Alliance Apple Developer certificates

lib/compose.js

@@ -26,7 +26,7 @@ const composeFlags = {
 const defaultOptions = {
   build: {noCache: false, pull: true},
   down: {removeOrphans: true, volumes: true},
-  exec: {detach: false, noTTY: !process.stdin.isTTY},
+  exec: {detach: false, noTTY: !(process.stdin.isTTY && process.stdout.isTTY)},
   kill: {},
   logs: {follow: false, timestamps: false},
   ps: {q: true},

test/tty-allocation.spec.js

@@ -0,0 +1,147 @@
+/*
+ * Tests for TTY allocation in docker exec and compose.
+ * @file tty-allocation.spec.js
+ *
+ * Validates that TTY is only allocated when BOTH stdin and stdout
+ * are TTYs. When stdout is redirected (e.g. `lando foo > file.txt`),
+ * TTY should NOT be allocated so that ANSI escape codes are not
+ * written to the file.
+ *
+ * @see https://github.com/lando/core/issues/345
+ * @see https://github.com/lando/drupal/issues/157
+ */
+
+'use strict';
+
+const chai = require('chai');
+const expect = chai.expect;
+chai.should();
+
+describe('TTY allocation', () => {
+  // Save originals
+  const originalStdinIsTTY = process.stdin.isTTY;
+  const originalStdoutIsTTY = process.stdout.isTTY;
+
+  beforeEach(() => {
+    // Clear require cache so compose.js re-evaluates with test-set TTY values
+    delete require.cache[require.resolve('./../lib/compose')];
+    delete require.cache[require.resolve('./../utils/build-docker-exec')];
+  });
+
+  afterEach(() => {
+    // Restore after each test
+    process.stdin.isTTY = originalStdinIsTTY;
+    process.stdout.isTTY = originalStdoutIsTTY;
+    // Clear require cache so compose.js re-evaluates
+    delete require.cache[require.resolve('./../lib/compose')];
+    delete require.cache[require.resolve('./../utils/build-docker-exec')];
+  });
+
+  describe('compose exec (lib/compose.js)', () => {
+    it('should set noTTY=true when stdout is not a TTY (output redirected)', () => {
+      process.stdin.isTTY = true;
+      process.stdout.isTTY = false;
+      const compose = require('./../lib/compose');
+      const result = compose.run(
+        ['docker-compose.yml'],
+        'test_project',
+        {services: ['web'], cmd: ['echo', 'hello']},
+      );
+      // When noTTY is true, the -T flag should be in the command
+      expect(result.cmd).to.include('-T');
+    });
+
+    it('should set noTTY=false when both stdin and stdout are TTYs', () => {
+      process.stdin.isTTY = true;
+      process.stdout.isTTY = true;
+      const compose = require('./../lib/compose');
+      const result = compose.run(
+        ['docker-compose.yml'],
+        'test_project',
+        {services: ['web'], cmd: ['echo', 'hello']},
+      );
+      // When both are TTY, -T should NOT be in the command
+      expect(result.cmd).to.not.include('-T');
+    });
+
+    it('should set noTTY=true when stdin is not a TTY (non-interactive)', () => {
+      process.stdin.isTTY = false;
+      process.stdout.isTTY = true;
+      const compose = require('./../lib/compose');
+      const result = compose.run(
+        ['docker-compose.yml'],
+        'test_project',
+        {services: ['web'], cmd: ['echo', 'hello']},
+      );
+      expect(result.cmd).to.include('-T');
+    });
+
+    it('should set noTTY=true when neither stdin nor stdout is a TTY', () => {
+      process.stdin.isTTY = false;
+      process.stdout.isTTY = false;
+      const compose = require('./../lib/compose');
+      const result = compose.run(
+        ['docker-compose.yml'],
+        'test_project',
+        {services: ['web'], cmd: ['echo', 'hello']},
+      );
+      expect(result.cmd).to.include('-T');
+    });
+  });
+
+  describe('docker exec (utils/build-docker-exec.js)', () => {
+    it('should not include --tty when stdout is not a TTY', () => {
+      process.stdin.isTTY = true;
+      process.stdout.isTTY = false;
+      const buildDockerExec = require('./../utils/build-docker-exec');
+
+      let capturedCmd;
+      const injected = {
+        config: {dockerBin: 'docker'},
+        _config: {dockerBin: 'docker'},
+        shell: {
+          sh: (cmd, opts) => {
+            capturedCmd = cmd;
+            return Promise.resolve();
+          },
+        },
+      };
+
+      const datum = {
+        id: 'test_container',
+        cmd: ['echo', 'hello'],
+        opts: {user: 'www-data', environment: {}},
+      };
+
+      buildDockerExec(injected, 'inherit', datum);
+      expect(capturedCmd).to.not.include('--tty');
+    });
+
+    it('should include --tty when both stdin and stdout are TTYs', () => {
+      process.stdin.isTTY = true;
+      process.stdout.isTTY = true;
+      const buildDockerExec = require('./../utils/build-docker-exec');
+
+      let capturedCmd;
+      const injected = {
+        config: {dockerBin: 'docker'},
+        _config: {dockerBin: 'docker'},
+        shell: {
+          sh: (cmd, opts) => {
+            capturedCmd = cmd;
+            return Promise.resolve();
+          },
+        },
+      };
+
+      const datum = {
+        id: 'test_container',
+        cmd: ['echo', 'hello'],
+        opts: {user: 'www-data', environment: {}},
+      };
+
+      buildDockerExec(injected, 'inherit', datum);
+      expect(capturedCmd).to.include('--tty');
+    });
+  });
+});

utils/build-docker-exec.js

@@ -8,7 +8,7 @@ const _ = require('lodash');
 const getExecOpts = (docker, datum) => {
   const exec = [docker, 'exec'];
   // Should only use this if we have to
-  if (process.stdin.isTTY) exec.push('--tty');
+  if (process.stdin.isTTY && process.stdout.isTTY) exec.push('--tty');
   // Should only set interactive in node mode
   if (process.lando === 'node') exec.push('--interactive');
   // add workdir if we can