vscode: Extension get silently broken

Environment

• VSCode & OS Version:

Version: 1.33.1
Commit: 51b0b28134d51361cf996d2f0a1c698247aeabd8
Date: 2019-04-11T08:20:22.771Z
Electron: 3.1.6
Chrome: 66.0.3359.181
Node.js: 10.2.0
V8: 6.6.346.32
OS: Linux x64 4.15.0-48-generic

Steps to Reproduce

1. Update Dart Code to 2.26.1

Behavior

The extension do not seems to work (https://github.com/Dart-Code/Dart-Code/issues/1674).

No feedback from VS Code except in the console:

  ERR Unable to load and parse grammar for scope source.dart from file:///home/julien/.vscode/extensions/dart-code.dart-code-2.26.1/syntaxes/dart.json SyntaxError: Unexpected end of JSON input
    at JSON.parse (<anonymous>)
    at parseJSONGrammar (/usr/share/code/resources/app/node_modules.asar/vscode-textmate/release/main.js:1583)
    at parseRawGrammar (/usr/share/code/resources/app/node_modules.asar/vscode-textmate/release/main.js:1574)
    at t.<anonymous> (textMateService.ts:252)
    at Generator.next (<anonymous>)
    at r (errors.ts:184)
    at process._tickCallback (internal/process/next_tick.js:68)

  ERR No grammar provided for <source.dart: Error: No grammar provided for <source.dart
    at Registry.<anonymous> (/usr/share/code/resources/app/node_modules.asar/vscode-textmate/release/main.js:3583:39)
    at step (/usr/share/code/resources/app/node_modules.asar/vscode-textmate/release/main.js:3511:23)
    at Object.next (/usr/share/code/resources/app/node_modules.asar/vscode-textmate/release/main.js:3492:53)
    at fulfilled (/usr/share/code/resources/app/node_modules.asar/vscode-textmate/release/main.js:3483:58)
    at process._tickCallback (internal/process/next_tick.js:68:7)

  ERR Cannot read property 'comments' of undefined: TypeError: Cannot read property 'comments' of undefined
    at f._extractValidCommentRule (file:///usr/share/code/resources/app/out/vs/workbench/workbench.main.js:4002:202)
    at f._handleConfig (file:///usr/share/code/resources/app/out/vs/workbench/workbench.main.js:4005:546)
    at _fileService.resolveContent.then.s (file:///usr/share/code/resources/app/out/vs/workbench/workbench.main.js:4002:119)
    at process._tickCallback (internal/process/next_tick.js:68:7)

A file of the extension was empty (even after uninstalling / reinstalling).

Removing ~/.vscode/extensions/dart-code.dart-code-2.26.1 and updating eventually resolved the problem.

Note

Does this issue occur when all extensions are disabled?: No. It is an extension related problem.

/cc @DanTup