Access to fragment in router state on page refresh

[vasilich6107]

This PR fixes the issue #108614
Particularly this behaviour #108614 (comment)

Pre-launch Checklist

• I read the Contributor Guide and followed the process outlined there for submitting PRs.
• I read the Tree Hygiene wiki page, which explains my responsibilities.
• I read and followed the Flutter Style Guide, including Features we expect every widget to implement.
• I signed the CLA.
• I listed at least one issue that this PR fixes in the description above.
• I updated/added relevant documentation (doc comments with ///).
• I added new tests to check the change I am making, or this PR is test-exempt.
• All existing and new tests are passing.

[vasilich6107]

Hi @chunhtai
This is my PR for #108614

[chunhtai]

LGTM, but we should have one person from web team to also take a look at this pr

[vasilich6107]

Hi @mdebbar
Could you check my PR

[mdebbar]

The change looks good but I'm concerned that this might break existing applications that rely on a full match on the path, eg:

MaterialApp(
  initialRoute: '/',
  routes: {
    '/': (_) => HomePage(),
    '/profile': (_) => ProfilePage(),
    '/settings': (_) => SettingsPage(),
  },
)

If someone navigates to /profile or /profile#foo, they both work today. But after this PR, /profile#foo won't match with the /profile route name anymore because the hash became part of the path. @chunhtai is this a valid concern to worry about?

In order to avoid the breakage, I suggest one of two options:

1. Implement your own PathAndHashUrlStrategy as follows:

class PathAndHashUrlStrategy extends PathUrlStrategy {
  final BrowserPlatformLocation _platformLocation = BrowserPlatformLocation();

  @override
  String getPath() {
    return super.getPath() + _platformLocation.hash;
  }
}

void main() {
  setUrlStrategy(PathAndHashUrlStrategy());
  runApp(MyApp());
}

2. Make this new behavior optional by adding a includeHash boolean to the PathUrlStrategy constructor.

[chunhtai]

yes this seems like a possible breaking change.

2. seems more straight forward.

[vasilich6107]

Thanks for feedback
will implement 2.

[vasilich6107]

Hi @mdebbar
I added the flag.
Could you check if it looks good for you

[mdebbar]

Looks good to me! Thanks for the contribution!