`flutter doctor` should report whether the Flutter install dir is clean

[zoechi]

If the Flutter install directory contains any changes flutter doctor or flutter doctor -v should report that.

It would make it easier for support questions that are caused by inadvertently modified files in the Flutter install dir.

I created https://github.com/flutter/flutter/wiki/Workarounds-for-common-issues#flutter-installation-corrupted because this happens quite a lot.

See also #9218
I'd suggest to do the git clean -xfd git stash drop, ... when --force (flutter upgrade --force, flutter channel foo --force) is passed.
It might be useful to execute the git clean stuff with flutter upgrade --force even when no upgrade is available.

[zoechi]

See also

• flutter create fails “no pubspec.yaml found” #26222 (comment)
• Container() suddenly requires a positional argument #26275 (comment)

[kangwang1988]

Just git operation might not be enough. As some developers may have their own fork/branch, modifications.
It would be better to check based on some table/record staff, similar to #26069

[zoechi]

Somewhat related #14120, #18532

[zoechi]

Related #1963