Stuck on `Creating an optimized production build` forever when development server is running

[YassinEldeeb]

Verify canary release

• I verified that the issue exists in Next.js canary release

Provide environment information

Operating System:
Platform: win32
Arch: x64
Version: Windows 10 Pro
Binaries:
Node: 16.13.0
npm: N/A
Yarn: N/A
pnpm: 6.24.0-1
Relevant packages:
next: 12.1.4
react: 17.0.2
react-dom: 17.0.2

What browser are you using? (if relevant)

No response

How are you deploying your application? (if relevant)

No response

Describe the Bug

I had my development server running in the background without me remembering and I wanted to build my app using next build, that's what I've got:

$ yarn next build
yarn run v1.22.17
$ C:\development\activity-builder\node_modules\.bin\next build
info  - Loaded env from C:\development\activity-builder\.env
info  - Checking validity of types  
warn  - The Next.js plugin was not detected in your ESLint configuration. See https://nextjs.org/docs/basic-features/eslint#migrating-existing-config

./src/components/Activities/ActivityQuestions/DynamicQuestionTypes/MultipleChoice.tsx  
68:40  Warning: Forbidden non-null assertion.  @typescript-eslint/no-non-null-assertion
69:22  Warning: Forbidden non-null assertion.  @typescript-eslint/no-non-null-assertion

./src/components/Activities/ActivityQuestions/Question.tsx
102:13  Warning: Unexpected console statement.  no-console

info  - Need to disable some ESLint rules? Learn more here: https://nextjs.org/docs/basic-features/eslint#disabling-rules
info  - Creating an optimized production build  

And I was stuck for 30 minutes on info - Creating an optimized production build without any indication of anything being wrong, I noticed that the development server was running, after I've shut it down and ran next build again It compiled successfully.

Expected Behavior

• Run next build to compile the app for production even when I'm running the development server.

  OR

• Notify me that the development server is running and needs to be shut down before running next build, that's in case running next build when next is running isn't possible.

Link to reproduction

https://github.com/YassinEldeeb/Next.js-starter

To Reproduce

1. Run next for the development server.
2. Then run next build while the development server is running.

Note: It's not specific to the repository linked above.

[pulkitvyas08]

Facing the same issue

[huanlirui]

i have same issue !!

[huanlirui]

Execute the steps of “ creating an optimized production build ” on the Linux server

node v14.17.0

[benzavision]

same issue

[MarcusHSmith]

Same issue for us

[UmerEdava]

The same issue still exists.... any remedies. In my case, it was hours I stuck at this "creating an optimized production build". And also I didn't run the development server in the background.

[boiboif]

same issue!

[iamharshad]

Same issue for React.js project as well even when development server is not running on

[Dariocoding]

I have the same issue!!!

[zahydo]

Same Issue. In development it worked, but when I try to create the Docker image it stuck

[zahydo]

Same Issue. In development it worked, but when I try to create the Docker image it stuck

I solved with the next steps:

1. Upgrading Next to v12.2.5.
2. Removing local folders: .next, node_modules
3. Installing dependencies again: yarn install
4. Adding this to next-config.js: output: 'standalone'
5. Adding the next paths to the .dockerignore:
   Dockerfile
   .dockerignore
   node_modules
   npm-debug.log
   README.md
   .next
   docker
   .git
6. Creating the image again: docker build ...

[alexcmgit]

Stuck on Creating an optimized production build forever when development server is running.

Same issue but I wasn't aware that this was happening due the open dev webserver.

So the solution for me is on your title: close the development server, then run next build and next export (If you intend to deploy statically).