Can't add extensions in JupyterLab due to error in build

Question

Whenever I add extensions in JupyterLab, it asks me to change the build, but every time I run the command jupyter lab build I get the following error: RuntimeError: JupyterLab failed to build. I've tried various solutions from people asking the same question but none have worked. This is my log file when running this command:

[LabBuildApp] Building in c:\users\20-06\anaconda3\share\jupyter\lab
[LabBuildApp] Node v12.18.1

[LabBuildApp] Yarn configuration loaded.
[LabBuildApp] Building jupyterlab assets (build:prod:minimize)
[LabBuildApp] > node c:\users\20-06\anaconda3\lib\site-packages\jupyterlab\staging\yarn.js install --non-interactive
[LabBuildApp] yarn install v1.21.1
[1/5] Validating package.json...
[2/5] Resolving packages...
success Already up-to-date.
Done in 0.83s.

[LabBuildApp] > node c:\users\20-06\anaconda3\lib\site-packages\jupyterlab\staging\yarn.js yarn-deduplicate -s fewer --fail
[LabBuildApp] yarn run v1.21.1
$ c:\users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\.bin\yarn-deduplicate -s fewer --fail
Done in 0.69s.

[LabBuildApp] > node c:\users\20-06\anaconda3\lib\site-packages\jupyterlab\staging\yarn.js run build:prod:minimize
[LabBuildApp] yarn run v1.21.1
$ ensure-max-old-space webpack --config webpack.prod.minimize.config.js
ModuleNotFoundError: Module not found: Error: Can't resolve 'net' in 'c:\users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\vscode-languageserver-protocol\node_modules\vscode-jsonrpc\lib'
    at c:\Users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\webpack\lib\Compilation.js:925:10
    at c:\Users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\webpack\lib\NormalModuleFactory.js:401:22
    at c:\Users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\webpack\lib\NormalModuleFactory.js:130:21
    at c:\Users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\webpack\lib\NormalModuleFactory.js:224:22
    at c:\Users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\neo-async\async.js:2830:7
    at c:\Users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\neo-async\async.js:6877:13
    at c:\Users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\webpack\lib\NormalModuleFactory.js:214:25
    at c:\Users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\enhanced-resolve\lib\Resolver.js:184:12
    at c:\Users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\enhanced-resolve\lib\Resolver.js:238:5
    at eval (eval at create (c:\Users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\tapable\lib\HookCodeFactory.js:33:10), <anonymous>:13:1)
    at c:\Users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\enhanced-resolve\lib\UnsafeCachePlugin.js:37:5
    at c:\Users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\enhanced-resolve\lib\Resolver.js:238:5
    at eval (eval at create (c:\Users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\tapable\lib\HookCodeFactory.js:33:10), <anonymous>:13:1)
    at c:\Users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\enhanced-resolve\lib\Resolver.js:238:5
    at eval (eval at create (c:\Users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\tapable\lib\HookCodeFactory.js:33:10), <anonymous>:25:1)
    at c:\Users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\enhanced-resolve\lib\DescriptionFilePlugin.js:42:38
    at c:\Users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\enhanced-resolve\lib\Resolver.js:238:5
    at eval (eval at create (c:\Users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\tapable\lib\HookCodeFactory.js:33:10), <anonymous>:26:1)
    at c:\Users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\enhanced-resolve\lib\ModuleKindPlugin.js:23:37
    at c:\Users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\enhanced-resolve\lib\Resolver.js:238:5
    at eval (eval at create (c:\Users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\tapable\lib\HookCodeFactory.js:33:10), <anonymous>:13:1)
    at c:\Users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\enhanced-resolve\lib\Resolver.js:238:5
    at eval (eval at create (c:\Users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\tapable\lib\HookCodeFactory.js:33:10), <anonymous>:13:1)
    at c:\Users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\enhanced-resolve\lib\forEachBail.js:30:14
    at c:\Users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\enhanced-resolve\lib\Resolver.js:238:5
    at eval (eval at create (c:\Users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\tapable\lib\HookCodeFactory.js:33:10), <anonymous>:13:1)
    at c:\Users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\enhanced-resolve\lib\UnsafeCachePlugin.js:37:5
    at c:\Users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\enhanced-resolve\lib\Resolver.js:238:5
    at eval (eval at create (c:\Users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\tapable\lib\HookCodeFactory.js:33:10), <anonymous>:13:1)
    at c:\Users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\enhanced-resolve\lib\Resolver.js:238:5
    at eval (eval at create (c:\Users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\tapable\lib\HookCodeFactory.js:33:10), <anonymous>:25:1)
    at c:\Users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\enhanced-resolve\lib\DescriptionFilePlugin.js:42:38
    at c:\Users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\enhanced-resolve\lib\Resolver.js:238:5
    at eval (eval at create (c:\Users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\tapable\lib\HookCodeFactory.js:33:10), <anonymous>:14:1)
    at c:\Users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\enhanced-resolve\lib\Resolver.js:238:5
    at eval (eval at create (c:\Users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\tapable\lib\HookCodeFactory.js:33:10), <anonymous>:25:1)
resolve 'net' in 'c:\users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\vscode-languageserver-protocol\node_modules\vscode-jsonrpc\lib'
  Parsed request is a module
  using description file: c:\users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\vscode-languageserver-protocol\node_modules\vscode-jsonrpc\package.json (relative path: ./lib)
    Field 'browser' doesn't contain a valid alias configuration
    resolve as module
      c:\users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\vscode-languageserver-protocol\node_modules\vscode-jsonrpc\lib\node_modules doesn't exist or is not a directory
      c:\users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\vscode-languageserver-protocol\node_modules\vscode-jsonrpc\node_modules doesn't exist or is not a directory
      c:\users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\vscode-languageserver-protocol\node_modules\node_modules doesn't exist or is not a directory
      c:\users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\node_modules doesn't exist or is not a directory
      c:\users\20-06\anaconda3\share\jupyter\lab\node_modules doesn't exist or is not a directory
      c:\users\20-06\anaconda3\share\jupyter\node_modules doesn't exist or is not a directory
      c:\users\20-06\anaconda3\share\node_modules doesn't exist or is not a directory
      c:\users\20-06\anaconda3\node_modules doesn't exist or is not a directory
      c:\users\20-06\node_modules doesn't exist or is not a directory
      c:\users\node_modules doesn't exist or is not a directory
      c:\node_modules doesn't exist or is not a directory
      looking for modules in c:\users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\vscode-languageserver-protocol\node_modules
        using description file: c:\users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\vscode-languageserver-protocol\package.json (relative path: ./node_modules)
          Field 'browser' doesn't contain a valid alias configuration
      looking for modules in c:\users\20-06\anaconda3\share\jupyter\lab\staging\node_modules
        using description file: c:\users\20-06\anaconda3\share\jupyter\lab\staging\package.json (relative path: ./node_modules)
          Field 'browser' doesn't contain a valid alias configuration
          using description file: c:\users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\vscode-languageserver-protocol\package.json (relative path: ./node_modules/net)
            no extension
              Field 'browser' doesn't contain a valid alias configuration
          using description file: c:\users\20-06\anaconda3\share\jupyter\lab\staging\package.json (relative path: ./node_modules/net)
            no extension
              Field 'browser' doesn't contain a valid alias configuration
              c:\users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\vscode-languageserver-protocol\node_modules\net doesn't exist
            .wasm
              Field 'browser' doesn't contain a valid alias configuration
              c:\users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\net doesn't exist
            .wasm
              Field 'browser' doesn't contain a valid alias configuration
              c:\users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\vscode-languageserver-protocol\node_modules\net.wasm doesn't exist
            .mjs
              Field 'browser' doesn't contain a valid alias configuration
              c:\users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\net.wasm doesn't exist
            .mjs
              Field 'browser' doesn't contain a valid alias configuration
              c:\users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\vscode-languageserver-protocol\node_modules\net.mjs doesn't exist
            .js
              Field 'browser' doesn't contain a valid alias configuration
              c:\users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\net.mjs doesn't exist
            .js
              Field 'browser' doesn't contain a valid alias configuration
              c:\users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\vscode-languageserver-protocol\node_modules\net.js doesn't exist
            .json
              Field 'browser' doesn't contain a valid alias configuration
              c:\users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\net.js doesn't exist
            .json
              Field 'browser' doesn't contain a valid alias configuration
              c:\users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\vscode-languageserver-protocol\node_modules\net.json doesn't exist
              c:\users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\net.json doesn't exist
            as directory
              c:\users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\vscode-languageserver-protocol\node_modules\net doesn't exist
            as directory
              c:\users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\net doesn't exist
child_process.js:651
    throw err;
    ^

Error: Command failed: c:\users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\.bin\webpack.CMD --config webpack.prod.minimize.config.js
    at checkExecSyncError (child_process.js:630:11)
    at Object.execFileSync (child_process.js:648:15)
    at Object.<anonymous> (c:\Users\20-06\anaconda3\share\jupyter\lab\staging\node_modules\@jupyterlab\buildutils\lib\ensure-max-old-space.js:50:17)
    at Module._compile (internal/modules/cjs/loader.js:1138:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:1158:10)
    at Module.load (internal/modules/cjs/loader.js:986:32)
    at Function.Module._load (internal/modules/cjs/loader.js:879:14)
    at Function.executeUserEntryPoint [as runMain] (internal/modules/run_main.js:71:12)
    at internal/main/run_main_module.js:17:47 {
  status: 1,
  signal: null,
  output: [ null, null, null ],
  pid: 16432,
  stdout: null,
  stderr: null
}
error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.

[LabBuildApp] JupyterLab failed to build
[LabBuildApp] Traceback (most recent call last):

[LabBuildApp]   File "c:\users\20-06\anaconda3\lib\site-packages\jupyterlab\debuglog.py", line 47, in debug_logging
    yield

[LabBuildApp]   File "c:\users\20-06\anaconda3\lib\site-packages\jupyterlab\labapp.py", line 138, in start
    raise e

[LabBuildApp]   File "c:\users\20-06\anaconda3\lib\site-packages\jupyterlab\labapp.py", line 135, in start
    command=command, app_options=app_options)

[LabBuildApp]   File "c:\users\20-06\anaconda3\lib\site-packages\jupyterlab\commands.py", line 460, in build
    command=command, clean_staging=clean_staging)

[LabBuildApp]   File "c:\users\20-06\anaconda3\lib\site-packages\jupyterlab\commands.py", line 661, in build
    raise RuntimeError(msg)

[LabBuildApp] RuntimeError: JupyterLab failed to build

[LabBuildApp] Exiting application: JupyterLab

There are a million errors, but I am not sure what is causing it. Any help would be appreciated.

Answer 1

This is most likely due to another extension you have installed in jupyterlab (for me it was jupyterlab-latex).

Quick googling based on your error path says that in your case it might be jupyter-lsp (note: it has upper limit on jupyterlab version of <2.1.0a0). Try

jupyter labextension uninstall @krassowski/jupyterlab-lsp
pip uninstall jupyter-lsp
jupyter lab build