Suggestion: hide the script snapshot version errors when running dart script

[DartBot]

<img src="https://avatars.githubusercontent.com/u/5479?v=3" align="left" width="96" height="96"hspace="10"> Issue by sethladd
Originally opened as dart-lang/sdk#22308

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Hi,

Usability/aesthetics request. When changing your Dart version, and then running a script from pub's bin cache, we'll see this:

sethladd@sethladd-macbookair ~/tmp/angulartest $ stagehand ubersimplewebapp
Wrong script snapshot version, expected '9b71a36fb6f35a4247b4baef055b2626' found '836a274342f7f88d6b5a9bb59b2649a9'
Wrong script snapshot version, expected '9b71a36fb6f35a4247b4baef055b2626' found '836a274342f7f88d6b5a9bb59b2649a9'
Creating ubersimplewebapp application 'angulartest':
  /Users/sethladd/tmp/angulartest/.gitignore
  /Users/sethladd/tmp/angulartest/CHANGELOG.md
  /Users/sethladd/tmp/angulartest/LICENSE
  /Users/sethladd/tmp/angulartest/README.md
  /Users/sethladd/tmp/angulartest/pubspec.yaml
  /Users/sethladd/tmp/angulartest/web/index.html
  /Users/sethladd/tmp/angulartest/web/main.dart
  /Users/sethladd/tmp/angulartest/web/styles/main.css
8 files written.

--> to provision required packages, run 'pub get'
sethladd@sethladd-macbookair ~/tmp/angulartest $

Notice the two "wrong script snapshot version" messages. Two messages is a bit weird, and the message itself isn't that useful to an end user.

Could we display something more user friendly? Suggestion: "Dart VM version changed, generating new snapshot for app"

Thanks!

[DartBot]

<img src="https://avatars.githubusercontent.com/u/188?v=3" align="left" width="48" height="48"hspace="10"> Comment by nex3

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I'd dearly love to get rid of this message, but unfortunately the VM provides no way to control it (issue dart-lang/sdk#20784) and no alternate way to check if a snapshot is up-to-date (issue dart-lang/sdk#20802).

In theory we could try to filter the executable's stdout for this specific message, but in practice doing this in both the binstub scripts and pub itself a way that doesn't cause further problems is nearly impossible.

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Marked this as being blocked by dart-lang/sdk#20784, dart-lang/sdk#20802.

[sigurdm]

This might still be relevant - and seems to still be blocked on the vm issues.