refactor: migrate to shared eslint config by eablack · Pull Request #3661 · heroku/cli

eablack · 2026-04-14T16:09:45Z

Summary

Migrates the project from ESLint 8 with legacy .eslintrc.cjs to ESLint 9 with flat config (eslint.config.js), adopting the shared eslint configuration from @heroku-cli/test-utils. This reduces duplication across Heroku CLI projects and ensures consistent linting rules.

This PR primarily focuses on:

ESLint 9 migration and shared config adoption
Migrating test helpers to use utilities from @heroku-cli/test-utils (runCommand, expectOutput, etc.)
Applying linting fixes across unit tests (test/unit directory)
Adding semi: ['warn', 'never'] rule to enforce no-semicolon style
Fixing ESLint getter-return conflicts with proper TypeScript patterns

Note: Test helper, fixture, acceptance, and integration test linting changes are being handled in a separate PR (#3671).

Key changes:

Removed legacy .eslintrc.cjs and .eslintignore files
Created new eslint.config.js using ESLint 9 flat config format
Added @heroku-cli/test-utils dependency for shared linting rules and test utilities
Removed redundant eslint plugin dependencies (now handled by shared config)
Updated test helpers to import from @heroku-cli/test-utils instead of local implementations
Applied linting fixes to ~300 unit test files
Updated minor source file linting issues (dyno.ts, members/add.ts, etc.)
Updated dependencies (chai 4→5, nock 13→14, typescript-eslint 8.57→8.58)

Type of Change

Patch Updates (patch semver update)

refactor: Refactoring existing code without changing behavior

Testing

Notes:

All existing tests should pass with the new linting configuration
Linting rules are now consistent with other Heroku CLI projects
No functional changes - only formatting, linting, and test helper migration

Steps:

Run npm run lint to verify all linting rules pass
Run npm test to ensure all tests pass
Verify CI checks pass (Passing CI suffices)

- Rename test/helpers/runCommand.ts to legacy-run-command.ts for old-style tests - Replace local run-command.ts with shared implementation from @heroku-cli/test-utils - Update 226+ test files to import runCommand from @heroku-cli/test-utils - Rename helper files to kebab-case: testInstances.ts -> test-instances.ts, uxStub.ts -> ux-stub.ts - Consolidate test utilities to use shared @heroku-cli/test-utils package This reduces code duplication and ensures all tests use the same command runner implementation.

- Replace local test/helpers/utils/expectOutput.ts with shared implementation - Update 57 test files to import expectOutput from @heroku-cli/test-utils - Use named import syntax for consistency with other test-utils exports This continues the consolidation of test utilities into the shared package.

Remove eslint plugins that are now handled by shared config. Also fix URL construction in exec.ts to avoid duplicate slashes in the API path.

The shared eslint config requires eslint-import-resolver-typescript v4.x for ESLint 9 flat config compatibility. Without it explicitly installed, npm resolves to v3.x from eslint-config-oclif, which has an incompatible interface and causes "invalid interface loaded as resolver" errors.

The bin/run.js file imports from the dist folder, which needs to exist before linting can resolve those imports. Running build before lint ensures the TypeScript compiler generates the dist folder first.

Use ternary expression with explicit return to satisfy getter-return rule while avoiding no-useless-return. Added explicit return type annotation for clarity.

- Add semi: ['warn', 'never'] to eslint config for no semicolons preference - Fix unicorn/prefer-ternary warning in members/add.ts - Remove unnecessary no-var from eslint-disable comment - Use String.raw for better backslash escaping in tests - Reorder imports and alphabetize mock properties

Replace try-catch blocks with error property destructuring from runCommand across 88 test cases in 23 test files. This simplifies error handling by using the error returned directly from runCommand instead of relying on catch blocks.

Fix 6 test files where error handling was incorrectly using expect.fail, try-catch blocks, or expect().to.be.rejected instead of properly checking the error property returned by runCommand. This resolves 9 test failures.

Import HTTPError type and cast error to access body property, resolving TypeScript compilation error.

Replace stdout-stderr package with captureOutput from @heroku-cli/test-utils for cleaner and more consistent test output handling. Converted 7 test files and removed the stdout-stderr dependency from package.json. Files converted: - lib/confirm-command.unit.test.ts - lib/spaces/peering.unit.test.ts - lib/spaces/spaces.unit.test.ts - lib/run/log-displayer.unit.test.ts - lib/spaces/hosts.unit.test.ts - lib/data/display-quota.unit.test.ts - lib/spaces/vpn-connections.unit.test.ts

The log-displayer tests that expect errors were wrapping displayer.display() in captureOutput, which was causing the tests to hang. Since these tests are only checking error messages and not stdout/stderr output, we can remove the captureOutput wrapper and catch the errors directly in try-catch blocks.

The MockEventSource was creating setTimeout calls that weren't being cleaned up. These orphaned timers kept the Node.js event loop alive, causing the test suite to hang with a 30+ second timeout. Now we track all timeout IDs and clear them in the close() method to ensure proper cleanup.

The container/release test was calling stdMocks.use() to hijack stdout/stderr but never calling stdMocks.restore(). This left stdout/stderr in a broken state, causing the test runner to malfunction and exit after the release tests completed, preventing subsequent test files from running. Added stdMocks.flush() and stdMocks.restore() calls to properly clean up after capturing output.

michaelmalave

Left one comment but otherwise this looks good.

The container/release test was using stdMocks.use() to capture stdout/stderr, but then checking the output from runCommand() which already captures output. This was redundant and the missing stdMocks.restore() was breaking the test runner by leaving stdout/stderr hijacked, causing the test suite to exit early. Removed: - stdMocks usage from container/release test since runCommand() handles capture - std-mocks dependency from package.json (no longer used anywhere)

The tests that expect errors to be thrown shouldn't use captureOutput because captureOutput doesn't return an error property. When an error is thrown inside captureOutput, it gets swallowed and the test fails with the expect.fail() message instead of properly catching the error. Removed captureOutput wrapper from the two tests that expect errors, since we don't need to capture stdout/stderr when we're just checking that an error is thrown.

Fixed various linting warnings including: - Adding explicit type imports (e.g., SinonStub) - Addressing other ESLint warnings - Cleaning up test file patterns Updated 65 test files across commands, lib, and unit test directories.

Fixed linting warnings related to sinon usage across test files: - Added explicit type imports for sinon types - Cleaned up sinon stub and spy patterns - Fixed other sinon-related ESLint warnings Updated 17 test files.

Fixed additional linting warnings related to sinon usage: - Added explicit type imports for sinon types - Cleaned up sinon stub, spy, and sandbox patterns - Fixed sinon-related ESLint warnings Updated 19 test files across commands, hooks, and lib directories.

eablack requested a review from a team as a code owner April 14, 2026 16:09

eablack temporarily deployed to AcceptanceTests April 14, 2026 16:09 — with GitHub Actions Inactive

eablack force-pushed the eb/move-to-shared-eslint branch from 8ee63aa to 303d032 Compare April 14, 2026 17:14

eablack temporarily deployed to AcceptanceTests April 14, 2026 17:14 — with GitHub Actions Inactive

eablack temporarily deployed to AcceptanceTests April 14, 2026 17:33 — with GitHub Actions Inactive

eablack marked this pull request as draft April 14, 2026 18:08

eablack mentioned this pull request Apr 14, 2026

refactor: rename lib and script files to kebab-case #3663

Merged

1 task

eablack force-pushed the eb/move-to-shared-eslint branch from bcac179 to 4904a1c Compare April 14, 2026 21:06

eablack temporarily deployed to AcceptanceTests April 14, 2026 21:07 — with GitHub Actions Inactive

This was referenced Apr 14, 2026

refactor: apply lint formatting to access, accounts, addons, and apps commands #3664

Merged

refactor: apply lint formatting to auth through features commands #3665

Merged

refactor: apply lint formatting to git through pg commands #3666

Merged

eablack force-pushed the eb/move-to-shared-eslint branch from 4904a1c to 3b6e983 Compare April 14, 2026 21:59

eablack temporarily deployed to AcceptanceTests April 14, 2026 21:59 — with GitHub Actions Inactive

eablack mentioned this pull request Apr 14, 2026

refactor: apply lint formatting to remaining commands #3667

Merged

8 tasks

eablack added 9 commits April 16, 2026 09:04

turn off camelcase lint warnings

7e52f34

refactor: remove unused eslint dependencies and fix exec URL path

d6bd3b0

Remove eslint plugins that are now handled by shared config. Also fix URL construction in exec.ts to avoid duplicate slashes in the API path.

ci: build before linting to ensure dist folder exists

fc1fb35

The bin/run.js file imports from the dist folder, which needs to exist before linting can resolve those imports. Running build before lint ensures the TypeScript compiler generates the dist folder first.

remove conflict resolution marker

0d14599

fix: resolve ESLint getter-return conflict in _useSSH

a79688e

Use ternary expression with explicit return to satisfy getter-return rule while avoiding no-useless-return. Added explicit return type annotation for clarity.

eablack force-pushed the eb/move-to-shared-eslint branch from e72a630 to c4eb1d7 Compare April 16, 2026 16:05

eablack temporarily deployed to AcceptanceTests April 16, 2026 16:05 — with GitHub Actions Inactive

eablack temporarily deployed to AcceptanceTests April 16, 2026 21:45 — with GitHub Actions Inactive

eablack added 6 commits April 16, 2026 14:51

test: fix error handling assertions in failing tests

523b529

Fix 6 test files where error handling was incorrectly using expect.fail, try-catch blocks, or expect().to.be.rejected instead of properly checking the error property returned by runCommand. This resolves 9 test failures.

test: fix TypeScript error in apps/join test

7b8ae97

Import HTTPError type and cast error to access body property, resolving TypeScript compilation error.

michaelmalave approved these changes Apr 16, 2026

View reviewed changes

Comment thread src/commands/members/add.ts

eablack added 7 commits April 16, 2026 16:53

fix linting

18c81e3

fix: resolve linting warnings across test files

1e55ebb

Fixed various linting warnings including: - Adding explicit type imports (e.g., SinonStub) - Addressing other ESLint warnings - Cleaning up test file patterns Updated 65 test files across commands, lib, and unit test directories.

fix: resolve additional sinon-related linting warnings

32adbe6

Fixed linting warnings related to sinon usage across test files: - Added explicit type imports for sinon types - Cleaned up sinon stub and spy patterns - Fixed other sinon-related ESLint warnings Updated 17 test files.

add --all to coverage report, convert more sinon imports

a441442

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refactor: migrate to shared eslint config#3661

refactor: migrate to shared eslint config#3661
eablack merged 26 commits intomainfrom
eb/move-to-shared-eslint

eablack commented Apr 14, 2026 •

edited

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eablack commented Apr 14, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Summary

Type of Change

Patch Updates (patch semver update)

Testing

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eablack commented Apr 14, 2026 •

edited

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