CLI: Fix Ctrl+C termination on Windows after `npm create storybook@latest` by Copilot · Pull Request #33960 · storybookjs/storybook

Copilot · 2026-02-28T19:26:13Z

On Windows, after npm create storybook@latest completes and auto-starts the dev server, Ctrl+C has no effect — the only escape is closing the terminal.

Root Cause

The root cause is a known issue in @clack/core (bombshell-dev/clack#408): the block() function (used internally by spinners during dependency installation) sets stdin.setRawMode(true) on all platforms, but intentionally skips setRawMode(false) cleanup on Windows (!isWindows && setRawMode(false)). After init completes, stdin remains in raw mode, causing Ctrl+C to emit \x03 as a character instead of triggering SIGINT — so no signal handler ever fires.

Changes

Restore stdin cooked mode before starting dev server: After doInitiate() completes on Windows, explicitly calls process.stdin.setRawMode(false) (when stdin is a TTY and still in raw mode) to work around the clack bug and ensure Ctrl+C correctly triggers SIGINT.

// Workaround for https://github.com/bombshell-dev/clack/issues/408
if (process.platform === 'win32' && process.stdin.isTTY && process.stdin.isRaw) {
  process.stdin.setRawMode(false);
}

Explicit signal handling in runStorybookDev (defense-in-depth): Register SIGINT/SIGTERM handlers before awaiting the subprocess. On signal:
- Windows: spawnSync('taskkill', ['/T', '/F', '/PID', <pid>]) — forcefully kills the entire process tree, bypassing any residual cmd.exe batch-job prompt interception
- Non-Windows: subprocess.kill() — standard kill, sufficient since Unix process groups already propagate signals
- process.exit(0) — ensures the parent exits cleanly in both cases
Cleanup: process.off in a finally block removes handlers if the subprocess exits normally
Removed the stale commented-out process.on('SIGINT', ...) placeholder

No new dependencies — spawnSync is a Node.js built-in. taskkill /T /F is available on all Windows versions.

Original prompt

This section details on the original issue you should resolve

<issue_title>[Bug]: After running npm create storybook@latest in Windows, the program cannot be terminated using Ctrl+C</issue_title>
<issue_description>### Describe the bug

This issue occurs in both PowerShell and CMD.

After npm create storybook@latest completes, Storybook automatically runs, and at this point, it cannot be stopped with Ctrl+C; the only way to terminate it is by closing the command line.

Reproduction link

...

Reproduction steps

In PowerShell or CMD

npm create storybook@latest

cd vite-project

npm create storybook@latest

Ctrl+C

System
│  System:
│  OS: Windows 11 10.0.22631
│  CPU: (20) x64 12th Gen Intel(R) Core(TM) i7-12700H
│  Binaries:
│  Node: 24.7.0 - C:\nvm4w\nodejs\node.EXE
│  Yarn: 4.10.3 - C:\nvm4w\nodejs\yarn.CMD
│  npm: 11.5.1 - C:\nvm4w\nodejs\npm.CMD <----- active
│  pnpm: 10.17.1 - C:\nvm4w\nodejs\pnpm.CMD
│  Browsers:
│  Chrome: 145.0.7632.117
Additional context

No response</issue_description>

Comments on the Issue (you are @copilot in this section)

Fixes [Bug]: After running npm create storybook@latest in Windows, the program cannot be terminated using Ctrl+C #33959

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Summary by CodeRabbit

Bug Fixes
- Improved process termination reliability when stopping the Storybook dev server, particularly on Windows platforms.
- Enhanced signal handling to ensure Ctrl+C properly shuts down all child processes without leaving orphaned processes behind.

…book dev after init Co-authored-by: valentinpalkovic <5889929+valentinpalkovic@users.noreply.github.com>

github-actions · 2026-02-28T20:46:36Z

	Fails
🚫	PR is not labeled with one of: ["cleanup","BREAKING CHANGE","feature request","bug","documentation","maintenance","build","dependencies"]
🚫	PR description is missing the mandatory "#### Manual testing" section. Please add it so that reviewers know how to manually test your changes.

Generated by 🚫 dangerJS against 415398c

ia319 · 2026-03-01T11:21:39Z

@copilot
Consider addressing bombshell-dev/clack#408 as the root cause for the fix.

The block() function of @clack/core sets stdin.setRawMode(true) on all platforms, but intentionally skips cleanup on Windows (!isWindows && setRawMode(false)). This causes raw mode to remain active after the spinner from a dependency installation ends. As a result, Ctrl+C is treated as a regular character \x03, which does not trigger SIGINT, preventing interruption.

valentinpalkovic · 2026-03-02T19:44:26Z

@copilot

Consider addressing bombshell-dev/clack#408 as the root cause for the fix.

The block() function of @clack/core sets stdin.setRawMode(true) on all platforms, but intentionally skips cleanup on Windows (!isWindows && setRawMode(false)). This causes raw mode to remain active after the spinner from a dependency installation ends. As a result, Ctrl+C is treated as a regular character \x03, which does not trigger SIGINT, preventing interruption.

… Ctrl+C Co-authored-by: valentinpalkovic <5889929+valentinpalkovic@users.noreply.github.com>

Copilot · 2026-03-02T19:49:30Z

@copilot
Consider addressing bombshell-dev/clack#408 as the root cause for the fix.

...

Good catch — that's the real root cause. Fixed in 415398c.

@clack/core's block() function (called internally by spinners) sets stdin.setRawMode(true) on all platforms but intentionally skips setRawMode(false) on Windows during cleanup (!isWindows && setRawMode(false)). After the init process completes, stdin remains in raw mode, so Ctrl+C emits \x03 as a raw character instead of triggering SIGINT — meaning signal handlers never fire.

The fix explicitly calls process.stdin.setRawMode(false) right before starting the dev server on Windows (when stdin is a TTY and is in raw mode), restoring normal interrupt behavior. The existing SIGINT/SIGTERM handler with taskkill provides additional defense-in-depth for process tree cleanup.

@copilot

Consider addressing bombshell-dev/clack#408 as the root cause for the fix.
...

Addressed in 415398c. Added process.stdin.setRawMode(false) before starting the dev server on Windows to work around bombshell-dev/clack#408.

nx-cloud · 2026-03-06T08:01:00Z

View your CI Pipeline Execution ↗ for commit 415398c

Command	Status	Duration	Result
`nx run-many -t compile,check,knip,test,pretty-d...`	❌ Failed	10m 1s	View ↗

☁️ Nx Cloud last updated this comment at 2026-03-06 08:12:15 UTC

coderabbitai · 2026-03-06T08:07:07Z

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: 3c4bca19-ffc3-4a01-ad88-51345a7626e9

📥 Commits

Reviewing files that changed from the base of the PR and between 2b8e827 and 415398c.

📒 Files selected for processing (1)

code/lib/create-storybook/src/initiate.ts

📝 Walkthrough

Walkthrough

Modified the Storybook dev initialization process to handle clean process termination across platforms. Added Windows-specific subprocess tree cleanup using taskkill and signal handlers, along with stdin raw-mode reset for Windows TTY environments. These changes ensure reliable Ctrl+C behavior and proper process cleanup.

Changes

Cohort / File(s)	Summary
Process Termination & Signal Handling `code/lib/create-storybook/src/initiate.ts`	Added Windows-specific signal handlers (SIGINT/SIGTERM) to kill subprocess tree via taskkill; Unix platforms use subprocess.kill(). Added stdin raw-mode reset for Windows TTY. Introduced cleanup via finally block to unregister handlers.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Possibly related PRs

storybookjs/storybook#32929: Modifies the same runStorybookDev function with subprocess spawning logic that directly relates to the signal handling and cleanup mechanisms introduced here.

✨ Finishing Touches

📝 Generate docstrings (stacked PR)
📝 Generate docstrings (commit on current branch)

_{Comment @coderabbitai help to get the list of available commands and usage tips.}

storybook-app-bot · 2026-03-06T08:12:23Z

Package Benchmarks

^{Commit: 415398c, ran on 6 March 2026 at 08:12:20 UTC}

The following packages have significant changes to their size or dependencies:

`@storybook/builder-webpack5`

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Dependency count	185	185	0
Self size	76 KB	76 KB	0 B
Dependency size	32.19 MB	32.17 MB	🎉 -19 KB 🎉
Bundle Size Analyzer	Link	Link

`@storybook/angular`

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Dependency count	185	185	0
Self size	139 KB	139 KB	0 B
Dependency size	30.40 MB	30.38 MB	🎉 -19 KB 🎉
Bundle Size Analyzer	Link	Link

`@storybook/ember`

	Before	After	Difference
Dependency count	189	189	0
Self size	15 KB	15 KB	🚨 +18 B 🚨
Dependency size	28.90 MB	28.88 MB	🎉 -19 KB 🎉
Bundle Size Analyzer	Link	Link

`@storybook/nextjs`

	Before	After	Difference
Dependency count	534	534	0
Self size	648 KB	648 KB	🎉 -120 B 🎉
Dependency size	59.86 MB	59.84 MB	🎉 -19 KB 🎉
Bundle Size Analyzer	Link	Link

`@storybook/nextjs-vite`

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Dependency count	92	92	0
Self size	1.12 MB	1.12 MB	0 B
Dependency size	22.47 MB	22.45 MB	🎉 -19 KB 🎉
Bundle Size Analyzer	Link	Link

`@storybook/react-native-web-vite`

	Before	After	Difference
Dependency count	124	124	0
Self size	30 KB	30 KB	0 B
Dependency size	23.76 MB	23.74 MB	🎉 -19 KB 🎉
Bundle Size Analyzer	Link	Link

`@storybook/react-vite`

	Before	After	Difference
Dependency count	82	82	0
Self size	35 KB	35 KB	0 B
Dependency size	20.25 MB	20.24 MB	🎉 -19 KB 🎉
Bundle Size Analyzer	Link	Link

`@storybook/react-webpack5`

	Before	After	Difference
Dependency count	271	271	0
Self size	24 KB	24 KB	🚨 +12 B 🚨
Dependency size	44.53 MB	44.51 MB	🎉 -19 KB 🎉
Bundle Size Analyzer	Link	Link

`@storybook/server-webpack5`

	Before	After	Difference
Dependency count	197	197	0
Self size	16 KB	16 KB	🎉 -12 B 🎉
Dependency size	33.44 MB	33.42 MB	🎉 -19 KB 🎉
Bundle Size Analyzer	Link	Link

`@storybook/cli`

	Before	After	Difference
Dependency count	183	183	0
Self size	779 KB	779 KB	0 B
Dependency size	67.35 MB	67.32 MB	🎉 -27 KB 🎉
Bundle Size Analyzer	Link	Link

`@storybook/codemod`

	Before	After	Difference
Dependency count	176	176	0
Self size	32 KB	32 KB	0 B
Dependency size	65.87 MB	65.85 MB	🎉 -28 KB 🎉
Bundle Size Analyzer	Link	Link

`@storybook/preset-react-webpack`

	Before	After	Difference
Dependency count	167	167	0
Self size	18 KB	18 KB	0 B
Dependency size	31.40 MB	31.38 MB	🎉 -19 KB 🎉
Bundle Size Analyzer	Link	Link

`@storybook/react`

	Before	After	Difference
Dependency count	58	58	0
Self size	1.19 MB	1.19 MB	🚨 +6 B 🚨
Dependency size	13.21 MB	13.19 MB	🎉 -19 KB 🎉
Bundle Size Analyzer	Link	Link

valentinpalkovic · 2026-03-19T11:07:17Z

I am closing this since we are waiting for a proper resolution of bombshell-dev/clack#408

Initial plan

8faa837

Copilot AI assigned Copilot and valentinpalkovic Feb 28, 2026

Copilot started work on behalf of valentinpalkovic February 28, 2026 19:26 View session

fix: properly handle Ctrl+C termination on Windows when running story…

ad65ef5

…book dev after init Co-authored-by: valentinpalkovic <5889929+valentinpalkovic@users.noreply.github.com>

Copilot AI changed the title ~~[WIP] Fix bug with terminating storybook on Windows~~ fix: Ctrl+C cannot terminate Storybook dev server on Windows after npm create storybook@latest Feb 28, 2026

Copilot stopped work on behalf of valentinpalkovic due to an error February 28, 2026 19:40
The "Compile" custom setup step from your .github/workflows/copilot-setup-steps.yml file failed.

Copilot started work on behalf of valentinpalkovic March 2, 2026 19:44 View session

fix: reset stdin raw mode on Windows before running dev server to fix…

415398c

… Ctrl+C Co-authored-by: valentinpalkovic <5889929+valentinpalkovic@users.noreply.github.com>

Copilot stopped work on behalf of valentinpalkovic due to an error March 2, 2026 19:50
The "Compile" custom setup step from your .github/workflows/copilot-setup-steps.yml file failed.

valentinpalkovic changed the title ~~fix: Ctrl+C cannot terminate Storybook dev server on Windows after npm create storybook@latest~~ CLI: Fix Ctrl+C termination on Windows after npm create storybook@latest Mar 6, 2026

valentinpalkovic added cli windows ci:normal labels Mar 6, 2026

valentinpalkovic marked this pull request as ready for review March 6, 2026 08:01

github-actions Bot added the Stale label Mar 19, 2026

valentinpalkovic added this to Core Team Projects Mar 19, 2026

valentinpalkovic moved this to In Progress in Core Team Projects Mar 19, 2026

valentinpalkovic closed this Mar 19, 2026

github-project-automation Bot moved this from In Progress to Done in Core Team Projects Mar 19, 2026

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CLI: Fix Ctrl+C termination on Windows after `npm create storybook@latest`#33960

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`@storybook/builder-webpack5`

`@storybook/angular`

`@storybook/ember`

`@storybook/nextjs`

`@storybook/nextjs-vite`

`@storybook/react-native-web-vite`

`@storybook/react-vite`

`@storybook/react-webpack5`

`@storybook/server-webpack5`

`@storybook/cli`

`@storybook/codemod`

`@storybook/preset-react-webpack`

`@storybook/react`