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).
## How we determine the channel name
Historically, we used the current branch's upstream to figure out the current channel name. I have no idea why. I traced it back to https://github.com/flutter/flutter/pull/446/files where @abarth implement this and I reviewed that PR and left no comment on it at the time.
I think this is confusing. You can be on a branch and it tells you that your channel is different. That seems weird.
This PR changes the logic to uses the current branch as the channel name.
## How we display channels
The main reason this PR exists is to add channel descriptions to the `flutter channel` list:
```
ianh@burmese:~/dev/flutter/packages/flutter_tools$ flutter channel
Flutter channels:
master (tip of tree, for contributors)
main (tip of tree, follows master channel)
beta (updated monthly, recommended for experienced users)
stable (updated quarterly, for new users and for production app releases)
* foo_bar
Currently not on an official channel.
ianh@burmese:~/dev/flutter/packages/flutter_tools$
```
## Other changes
I made a few other changes while I was at it:
* If you're not on an official channel, we used to imply `--show-all`, but now we don't, we just show the official channels plus yours. This avoids flooding the screen in the case the user is on a weird channel and just wants to know what channel they're on.
* I made the tool more consistent about how it handles unofficial branches. Now it's always `[user branch]`.
* I slightly adjusted how unknown versions are rendered so it's clearer the version is unknown rather than just having the word "Unknown" floating in the output without context.
* Simplified some of the code.
* Made some of the tests more strict (checking all output rather than just some aspects of it).
* Changed the MockFlutterVersion to implement the FlutterVersion API more strictly.
* I made sure we escape the output to `.metadata` to avoid potential injection bugs (previously we just inlined the version and channel name verbatim with no escaping, which is super sketchy).
* Tweaked the help text for the `downgrade` command to be clearer.
* Removed some misleading text in some error messages.
* Made the `.metadata` generator consistent with the template file.
* Removed some obsolete code to do with the `dev` branch.
## Reviewer notes
I'm worried that there are implications to some of these changes that I am not aware of, so please don't assume I know what I'm doing when reviewing this code. :-)
...and various other minor cleanup:
* Moved "FLUTTER_STORAGE_BASE_URL" into a constant throughout the code. There are other strings that we should do that to but this one was relevant to the code I was changing.
* Fixed the logger's handling of slow warnings. Previously it deleted too much text. Fixed the test for that to actually verify it entirely, too.
* Made the logger delete the slow warning when it's finished.
* Fixed 'Please choose one (To quit, press "q/Q")' message to be the cleaner 'Please choose one (or "q" to quit)'.
* Added a debug toString to ValidationResult for debugging purposes (not used).
* In http_host_validator:
- Shortened constant names to be clearer (e.g. kPubDevHttpHost -> kPubDev).
- Added GitHub as a tested host since when you run `flutter` we hit that immediately.
- Renamed the check "Network resources".
- Updated the `slowWarning` of the check to say which hosts are pending.
- Removed all timeout logic. Timeouts violate our style guide.
- Removed `int.parse(... ?? '10')`; passing a constant to `int.parse` is inefficient.
- Replaced the `_HostValidationResult` class with `String?` for simplicity.
- Improved the error messages to be more detailed.
- Removed all checks that dependened on the stringification of exceptions. That's very brittle.
- Added a warning specifically for HandshakeException that talks about the implications (MITM attacks).
- Replaced exception-message-parsing logic with just calling `Uri.tryParse` and validating the result.
- Replaced a lot of list-filtering logic with just a single for loop to check the results.
- Replaced code that added a constant to a known-empty list with just returning a constant list.
- Revamped the logic for deciding which hosts to check to just use a single chain of if/else blocks instead of getters, lists literals with `if` expressions, `??`, functions, etc spread over multiple places in the code.
* refactoring to use `ver` command instead of `systeminfo`
* fix tests to match new approach
* adding another valid validator using brazil locale text
* refactor tests to use generic fake class `ver` arg + showing output from `ver` if unsuccessful
* update reason text in test
* fix reason text to be hard coded
* [tools]some ui polish for build ipa validation
* do not print out a few success validations
* rename installed type to success for more general usage
* forgot nit after reverting custom validation types and re-use doctor types
* normalize windows file path cases in flutter validator
* fix
* make comparison more accurate by checking .startsWith() rather than .contains()
* fix method name
* call path.canonicalize
* fix
Our current top crasher is an unclear error when ProcessManager fails to resolve an executable path. To fix this, we'd like to being adjusting the process resolution logic and adding more instrumentation to track failures. In order to begin the process, the ProcessManager has been folded back into the flutter tool
Move the intellij validator to its own file, and split off the tests. Remove globals from each, and remove dependency on a real jar/filesystem by creating a minimal version of the manifest xml and setting it up in the memory file system.
#47161
Remove globals from the flutter validator class, and refactor the tests into a separate file. Applies some other cleanup like adding doc comments, and making the doctor validator work like it is documented to work - removing the gen_snapshot check if the artifact is not downloaded instead of downloading all android artifacts.
#47161
