Ember hangs on JavaScript syntax error

ember server stuck on “building… [Babel: project > applyPatches]” this happens when a JavaScript syntax error

I have created a new project and I’m getting the same problem things I tried to do:

1. delete watchman
2. reinstall package.json
3. upgrade to newer version
4. delete package-lock.json and node_module and reinstall
5. update nodejs, update npm

and nothing work, this problem started when I did “npm update” , my old projects still working but the new ones are not

ember: 3.28.5 node: 14.19.1 npm: 6.14.16

I’m using nodenv for nodejs

and this is the last few lines of debug log

 ember-auto-import:analyzer updating imports for secondproject/components/upload-fi/component.js, 179 +1m
  ember-auto-import:analyzer Ignoring an unparseable file +10ms
  broccoli-persistent-filter:Babel > [Babel: secondproject] [Babel: secondproject#3162 -> derivePatches#3163] found 0 files invalidated due to dependency changes. +13ms
  fs-tree-diff: [Babel: secondproject#3162 -> derivePatches#3163] invalidation reason: 
  fs-tree-diff: before Entry { relativePath: 'secondproject/components/upload-fi/component.js', basePath: '/tmp/broccoli-2028251l6a6zVNzKjEG/out-266-analyzer_ember_auto_import_analyzer', mode: 33204, size: 176, mtime: 1648093444681 }
  fs-tree-diff:  entryB Entry { relativePath: 'secondproject/components/upload-fi/component.js', basePath: '/tmp/broccoli-2028251l6a6zVNzKjEG/out-266-analyzer_ember_auto_import_analyzer', mode: 33204, size: 179, mtime: 1648093517521 } +0ms
  broccoli-persistent-filter:Babel > [Babel: secondproject] [Babel: secondproject#3162 -> derivePatches#3163] derivePatches duration: 2.03 ms {"patches":1,"entries":54,"invalidations":{"dependencies":0,"count":0,"duration":"0.16 ms"},"walk":{"entries":54,"duration":"1.35 ms"}} +0ms
  async-promise-queue: started, with concurrency=3 +1ms
  async-disk-cache get: /tmp/khaled/if-you-need-to-delete-this-open-an-issue-async-disk-cache/60752e0420d2d76e324ee36db6a8377a3f7bb400/37c1f9418ee002127298279720a594fd329cf087 +1ms
⠙ building...   broccoli-persistent-filter:babel:parallel-api [Babel: secondproject#3162 -> applyPatches#3164] transformString is parallelizable +1ms
2022-03-24T03:45:17.555Z babel:config:loading:files:plugins Loaded plugin '/home/khaled/projects/thisIsMy/secondproject/node_modules/babel-plugin-htmlbars-inline-precompile/index.js' from '/home/khaled/projects/thisIsMy/secondproject'.
2022-03-24T03:45:17.556Z babel:config:loading:files:plugins Loaded plugin '/home/khaled/projects/thisIsMy/secondproject/node_modules/ember-cli-htmlbars/lib/colocated-babel-plugin.js' from '/home/khaled/projects/thisIsMy/secondproject'.
2022-03-24T03:45:17.556Z babel:config:loading:files:plugins Loaded plugin '/home/khaled/projects/thisIsMy/secondproject/node_modules/@babel/plugin-proposal-decorators/lib/index.js' from '/home/khaled/projects/thisIsMy/secondproject'.
2022-03-24T03:45:17.556Z babel:config:loading:files:plugins Loaded plugin '/home/khaled/projects/thisIsMy/secondproject/node_modules/@babel/plugin-proposal-private-property-in-object/lib/index.js' from '/home/khaled/projects/thisIsMy/secondproject'.
2022-03-24T03:45:17.556Z babel:config:loading:files:plugins Loaded plugin '/home/khaled/projects/thisIsMy/secondproject/node_modules/@babel/plugin-proposal-private-methods/lib/index.js' from '/home/khaled/projects/thisIsMy/secondproject'.
2022-03-24T03:45:17.556Z babel:config:loading:files:plugins Loaded plugin '/home/khaled/projects/thisIsMy/secondproject/node_modules/@babel/plugin-proposal-class-properties/lib/index.js' from '/home/khaled/projects/thisIsMy/secondproject'.
2022-03-24T03:45:17.556Z babel:config:loading:files:plugins Loaded plugin '/home/khaled/projects/thisIsMy/secondproject/node_modules/babel-plugin-debug-macros/src/index.js' from '/home/khaled/projects/thisIsMy/secondproject'.
2022-03-24T03:45:17.556Z babel:config:loading:files:plugins Loaded plugin '/home/khaled/projects/thisIsMy/secondproject/node_modules/babel-plugin-debug-macros/src/index.js' from '/home/khaled/projects/thisIsMy/secondproject'.
2022-03-24T03:45:17.557Z babel:config:loading:files:plugins Loaded plugin '/home/khaled/projects/thisIsMy/secondproject/node_modules/babel-plugin-module-resolver/lib/index.js' from '/home/khaled/projects/thisIsMy/secondproject'.
2022-03-24T03:45:17.557Z babel:config:loading:files:plugins Loaded plugin '/home/khaled/projects/thisIsMy/secondproject/node_modules/@babel/plugin-transform-modules-amd/lib/index.js' from '/home/khaled/projects/thisIsMy/secondproject'.
2022-03-24T03:45:17.557Z babel:config:loading:files:plugins Loaded preset '/home/khaled/projects/thisIsMy/secondproject/node_modules/@babel/preset-env/lib/index.js' from '/home/khaled/projects/thisIsMy/secondproject'.

[Windvis]

@rwjblue To reproduce:

1. Generate a new Ember app. The version doesn’t matter I tried versions between 3.24 and 4.3.
2. Start the app
3. Add a syntax error to a .js file and save it (I used app/app.js)
4. The process hangs on building... [Babel: project > applyPatches]

It also hangs when starting the app if it already has a syntax error somewhere so it’s not limited to rebuilds only.

Forcing the version of @babel/parser to be lower than 7.17.7 “fixes” the problem.

[benedikt]

Running the server with CI=true JOBS=0 ember s doesn’t really change anything. There are no error messages, it just hangs at “building…” until hitting CTRL+C when it changes to “cleaning up…” but still hangs indefinitely.

The only way to recover is killing the process, fixing the syntax error, and starting the server again.