Christopher Fujino 3246808cd2
[flutter_tools] cache flutter sdk version to disk (#124558)
Fixes https://github.com/flutter/flutter/issues/112833

Most of the actual changes here are in [packages/flutter_tools/lib/src/version.dart](https://github.com/flutter/flutter/pull/124558/files#diff-092e00109d9e1589fbc7c6de750e29a6ae512b2dd44e85d60028953561201605), while the rest is largely just addressing changes to the constructor of `FlutterVersion` which now has different dependencies.

This change makes `FlutterVersion` an interface with two concrete implementations:

1. `_FlutterVersionGit` which is mostly the previous implementation, and
2. `_FlutterVersionFromFile` which will read a new `.version.json` file from the root of the repo

The [`FlutterVersion` constructor](https://github.com/flutter/flutter/pull/124558/files#diff-092e00109d9e1589fbc7c6de750e29a6ae512b2dd44e85d60028953561201605R70) is now a factory that first checks if `.version.json` exists, and if so returns an instance of `_FlutterVersionFromGit` else it returns the fallback `_FlutterVersionGit` which will end up writing `.version.json` so that we don't need to re-calculate the version on the next invocation.

`.version.json` will be deleted in the bash/batch entrypoints any time we need to rebuild he tool (this will usually be because the user did `flutter upgrade` or `flutter channel`, or manually changed the commit with git).
2023-06-15 00:20:30 +00:00
..

Integration tests

These tests are not hermetic, and use the actual Flutter SDK. While they don't require actual devices, they run flutter_tester to test Dart VM and Flutter integration.

Use this command to run (from the flutter_tools directory):

../../bin/cache/dart-sdk/bin/dart run test test/integration.shard

You need to have downloaded the Dart SDK in your Flutter clone for this to work. Running ../../bin/flutter will automatically download it.

Coverage exclusion

These tests are expensive to run and do not give meaningful coverage information for the flutter tool (since they are black-box tests that run the tool as a subprocess, rather than being unit tests). For this reason, they are in a separate shard when running on continuous integration and are not run when calculating coverage.