Fix RangeError in _matchByNavigatorKeyForGoRoute during state restoration

[trippusultan]

Description

Fixes a crash in go_router's route matching logic that occurs during Android state restoration after the OS kills the Flutter process.

When newMatchedLocation is an empty string (not '/'), the offset computation newMatchedLocation.length + 1 produces 1, which exceeds uri.path.length when the URI path is also empty (which happens during restoration). This causes ''.substring(1) to throw an unhandled RangeError in release builds where the preceding assert() guards are stripped.

Changes

• Replaced the unguarded uri.path.substring(offset) with a clamped version: offset >= uri.path.length ? '' : uri.path.substring(offset)

Related

Fixes flutter/flutter#185948

Testing

• Run go_router unit tests
• Verify state restoration path no longer crashes

[flutter-dashboard]

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[gemini-code-assist]

Code Review

This pull request modifies packages/go_router/lib/src/match.dart to prevent potential out-of-bounds errors when extracting the remaining child path. It introduces a check to ensure the calculated offset does not exceed the length of uri.path, returning an empty string if it does. There are no review comments, and no further feedback is provided.

[trippusultan]

Added regression tests in the latest push. Two tests cover the edge cases that trigger the RangeError:

1. ShellRoute with empty child path (URI path doesn't start with route path)
2. Nested route with path shorter than matchedLocation

Both tests verify that RouteMatchBase.match() returns normally without throwing RangeError.

[stuartmorgan-g]

Thanks for the contribution!

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