Theia Extension Cannot apply @injectable decorator multiple times.

[dhananjayharel]

Description

I cannot create a new theia extension since today.
When I create a new helloworld extension by typing 'yo theia-extension xxxx'
it compiles but when I start the theia app and see the browser then the console shows following error

index.js:61 Failed to start the frontend application.
(anonymous) @ index.js:61
Promise.catch (async)
./src-gen/frontend/index.js @ index.js:60
__webpack_require__ @ bootstrap:63
(anonymous) @ bootstrap:198
(anonymous) @ bootstrap:198

index.js:63 Error: Cannot apply @injectable decorator multiple times.
    at injectable.js:8
    at DecorateConstructor (Reflect.js:541)
    at Object.decorate (Reflect.js:130)
    at _decorate (decorator_utils.js:42)
    at Object.decorate (decorator_utils.js:55)
    at Object.../node_modules/@theia/variable-resolver/node_modules/@theia/core/lib/browser/widgets/widget.js (widget.ts:27)
    at __webpack_require__ (bootstrap:63)
    at Object.../node_modules/@theia/variable-resolver/node_modules/@theia/core/lib/browser/widgets/index.js (index.ts:17)
    at __webpack_require__ (bootstrap:63)
    at Object.../node_modules/@theia/variable-resolver/node_modules/@theia/core/lib/browser/dialogs.js (dialogs.ts:20)

Here is the package.json in by browser-app

{
  "private": true,
  "name": "browser-app",
  "version": "0.0.0",
  "dependencies": {
    "@theia/core": "latest",
    "@theia/filesystem": "latest",
    "@theia/workspace": "latest",
    "@theia/preferences": "latest",
    "@theia/navigator": "latest",
    "@theia/process": "latest",
    "@theia/terminal": "latest",
    "@theia/editor": "latest",
    "@theia/languages": "latest",
    "@theia/markers": "latest",
    "@theia/monaco": "latest",
    "@theia/typescript": "latest",
    "@theia/messages": "latest",
    "programmr_php7": "0.0.0"
  },
  "devDependencies": {
    "@theia/cli": "latest"
  },
  "scripts": {
    "prepare": "theia build --mode development",    
    "start": "theia start",
    "watch": "theia build --watch --mode development"
  },
  "theia": {
    "target": "browser"
  }
}

Reproduction Steps

OS and Theia version:
Yarn version: 1.15.2
yo version: 2.0.6
Node version:10.15.3

Diagnostics:

[vince-fugnitto]

@dhananjayharel the error occurs since @theia/typescript has been deprecated and it's latest version is thus behind all other extensions.

It is generally not possible to mix-match versions of theia extensions as they will each pull different versions of @theia/core for instance which cannot be resolved, causing the multi-injector issue.

Checking npm you can see that @theia/typescript latest points to 0.15.0, while another extension like @theia/getting-started is at 0.16.1.

The fix has been made on the generator already in the most up-to-date version: eclipse-theia/generator-theia-extension#53

Additional Info:

• you can see the following pull-request for the list of deprecated extensions: Remove Deprecated Extensions #6933

[dhananjayharel]

Thanks.
I can compile the plugin after updating the plugin generator