Support `--no-pub` flag on `pub remove` (and potentially other subcommands)

[foxanna]

It would be fantastic to have a way to run dart pub remove without calling dart pub get. For example, with --no-pub flag:

dart pub remove http --no-pub

Reason for request

In our huge fin-tech mobile application, we have to have a lot of dependencies on native libraries of 3rd-party providers. We build multiple products from the same codebase, and those native dependencies do not always have to be included in a particular product. But they are not being tree-shaken by default, even if the entry point code does not hit the code path that makes calls to those libraries.

To work around this, we wrap every such dependency in a dedicated dart package wrapper. And, in case such a dependency should not be included, we run

dart pub remove <wrapper_package_name>

before building a mobile app for a certain product.

Given the scale of our application, we have on average 10 packages on which we have to call pub remove. This in turn leads to 10 extra dart pub get calls, which, on constraint environments like CI, takes about 1 minute each.

Being able to turn dart pub get call off with --no-pub, and then only running one dart pub get after all unwanted dependencies are removed, would allow us saving ~10 minutes with each build.

[sigurdm]

Without doing a resolution the package would only be removed from pubspec.yaml.

I don't know the reason that the packages are not being tree-shaken, but if they are only removed from pubspec.yaml I do not expect that they would be removed from the build at all. (And most likely flutter build would invoke pub get anyways if it sees that pubspec.yaml has been changed.).

Can you give some small reproduction where a package is being tree-shaken even though it is not used?
Perhaps there is some way to make tree-shaking work better.

[foxanna]

@sigurdm, thanks for picking this up!

Without doing a resolution the package would only be removed from pubspec.yaml.

This is indeed the outcome we are looking for. The point is not in avoiding calling dart pub get at all before building the app, but in doing it in controlled manner when we believe it is most efficient.

So instead of:

• call dart pub remove dependency (and thus dart pub get) ~10 times
• do "other stuff"
• call dart pub get because "other stuff" may have also impacted dependencies
• build the app with flutter build (which as you have pointed out "would invoke pub get anyways")

Our workflow can become

• call dart pub remove dependency --no-pub (without dart pub get) ~10 times
• do "other stuff"
• call dart pub get
• build the app with flutter build

This will save us ~10 unnecessary dart pub get calls, which as I mentioned earlier, would save us ~10 minutes of CI time with each build.

[sigurdm]

Ah - you want to batch multiple removes.

Did you know you can do

> dart pub remove pkg1 pkg2 pkg3 ... pkg10

[foxanna]

Did you know you can do
dart pub remove pkg1 pkg2 pkg3 ... pkg10

Yes, we do that already. The problem presents when we run dart pub remove ... on ~10 different packages.
This may sound surprising, but for our codebase of over 4M lines of Dart code and 600+ packages, it is a part of our project architecture.

[sigurdm]

Taking a step back, what version of Flutter are you on?

After flutter/flutter#160443 has landed, only the plugins from the actual apps transitive dependencies should be bundled with the app?

Could you try with the beta-channel of Flutter if this is still a problem for you?