Prompt to run "pub upgrade" upon opening a package if the SDK versions has changed

[DanTup]

When the user upgrades their SDK (a major or minor change, but not patch) there may be new versions of packages that were not available before (or that are required for some classes of changes). We should detect this change when we're checking if they need to run "pub get" (we can get the last version used to fetch packages from .dart_tool/package_config.json: ("generatorVersion": "2.19.0-374.0.dev")) and offer to run pub upgrade (in preference to pub get).

@devoncarew should we do this in both directions, or only one? It probably doesn't affect many users, but I realise that I often switch between SDK versions (for testing) and if I click pub upgrade on this prompt and then switch back to an older SDK, there's a possibility that I now have packages that are not valid. Would pub upgrade even fix this (I don't thinkpub downgrade is what's wanted here, because I want to go back to "the highest that is valid given this new (lower) SDK"?)

[devoncarew]

Interesting. I think the sdk downgrade case is pretty rare. I could see people running into it if they (intentionally) have multiple SDKs installed locally.

I would say we could either:

1. not handle it, or
2. handle it but switch to using pub get?

We'd mostly be concerned with package versions that solved into the newer sdk but that wouldn't solve into the older sdk.

[DanTup]

handle it but switch to using pub get?

Ah, I hadn't considered that that would fix it, that makes sense. So where today it's:

• if package_config is missing or timestamped older than pubspec
  • prompt to pub get

I think we probably want:

• if package_config is missing
  • prompt to pub get
• else if sdk major/minor version has increased since current package_config
  • prompt to pub upgrade
• else if package_config is timestamped older than pubspec or sdk major/minor version has decreased
  • prompt to pub get

?

[devoncarew]

sgtm!

[DanTup]

@devoncarew here's how this current looks (this prompt is just a special case of the pub-get check when you open a project or change your workspace folders):

Let me know if you have any suggestions for the text. It may also be useful to have a "More Info" button here that explains why this this is recommended. I can add something to the Dart-Code website, although perhaps it's better having something on the Dart website (or Wiki?) since this may be applicable to other editors (and CLI users)?

(I'm slightly worried that "Upgrade packages" might make it seem like this is going to change constraints in pubspec or similar, and people may skip clicking it unsure what it does)

[devoncarew]

The prompt looks great - thanks!

I'm slightly worried that "Upgrade packages" might make it seem like this is going to change constraints in pubspec or similar, and people may skip clicking it unsure what it does

It matches the 'get' packages prompt however? Instead of Upgrade packages we could say run dart pub upgrade? It's more technical but there'd be less uncertainty about what the tool is going to do. I'm not 100% sure this is an issue, but the command name would have slightly more clarity.

[DanTup]

Yeah, the other one said "Get packages". I've changed them to run 'pub get' and run 'pub upgrade' (I left off dart to be shorter and avoid confusion with flutter and this prompt may apply to multiple projects in the workspace), looks like this now (I changed "upgrade" to "updated" in the text as I think it reads a little better too, but happy to tweak):

[devoncarew]

Looks great - very clear about what it'll do (and makes sense to not specify the 'dart' or 'flutter' prefix).