Improve error message for type mismatch in Navigator.pop and maybePop.#186571
Merged
Conversation
github-actions
Bot
added
framework
![gemini-code-assist[bot]](https://avatars.githubusercontent.com/in/956858?s=60&v=4){kind=small}
Contributor
There was a problem hiding this comment.
Code Review
This pull request introduces a debug-time type check for Navigator results by adding the _debugCheckCanConsumeResult method to the Route class and integrating it into pop and maybePop. This change aims to provide clearer error messages when a route is popped with a mismatched result type. Feedback suggests using _lastRouteEntryWhereOrNull instead of lastWhere in the pop method to prevent a potential StateError if the navigation history is empty and to ensure consistency with the maybePop implementation.
puneetkukreja98
force-pushed
the
fix-16987
branch
from
May 15, 2026 10:05
b68e861 to
762181d
Compare
justinmc
previously approved these changes
May 15, 2026
justinmc
left a comment
justinmc
left a comment
Contributor
There was a problem hiding this comment.
LGTM minus a comment from Gemini. Thanks for making Flutter's error messages better!
navaronbracke
requested changes
May 15, 2026
Contributor
Author
|
Addressed the review comments:
@justinmc @navaronbracke could you please take another look? |
puneetkukreja98
force-pushed
the
fix-16987
branch
from
May 18, 2026 10:59
2f9916e to
7ef2e5e
Compare
justinmc
previously approved these changes
May 18, 2026
justinmc
left a comment
justinmc
left a comment
Contributor
There was a problem hiding this comment.
LGTM 👍 assuming the analyzer failure is fixed and tests pass.
navaronbracke
previously approved these changes
May 18, 2026
navaronbracke
left a comment
navaronbracke
left a comment
Contributor
There was a problem hiding this comment.
LGTM, modulo some typo fixes and something worth looking at in relation to the assert example
Contributor
|
Linux analyze is failing on formatting The Mac_x64 tool_tests_commands hit a crash that looks unrelated to your change, though (maybe rebase after fixing formatting?) Windows framework_tests_misc seems to have been terminated on the bot? |
victorsanni
previously approved these changes
May 18, 2026
puneetkukreja98
dismissed stale reviews from victorsanni, navaronbracke, and justinmc
via
May 19, 2026 18:24
68329f5
navaronbracke
previously approved these changes
May 19, 2026
puneetkukreja98
force-pushed
the
fix-16987
branch
from
May 19, 2026 18:27
68329f5 to
ab89dd6
Compare
chunhtai
added
the
autosubmit
auto-submit
Bot
removed
the
autosubmit
Contributor
|
autosubmit label was removed for flutter/flutter/186571, because - The status or check suite Google testing has failed. Please fix the issues identified (or deflake) before re-applying this label. |
chunhtai
added
CICD
auto-submit
Bot
removed
the
autosubmit
Contributor
|
autosubmit label was removed for flutter/flutter/186571, because - The status or check suite Mac_x64 tool_tests_commands has failed. Please fix the issues identified (or deflake) before re-applying this label. |
chunhtai
added
the
autosubmit
auto-submit
Bot
removed
the
autosubmit
Contributor
|
autosubmit label was removed for flutter/flutter/186571, because - The status or check suite Linux firebase_release_smoke_test has failed. Please fix the issues identified (or deflake) before re-applying this label. |
victorsanni
added
CICD
flutter-dashboard
Bot
removed
the
autosubmit
This was referenced Jun 3, 2026
auto-submit Bot
pushed a commit
to flutter/packages
that referenced
this pull request
Jun 3, 2026
…11832) Manual roll requested by [email protected] flutter/flutter@701665b...2ba5420 2026-06-03 [email protected] Roll Packages from 818b310 to b11504f (8 revisions) (flutter/flutter#187511) 2026-06-03 [email protected] Add new file patterns for team-web labeler (flutter/flutter#187397) 2026-06-03 [email protected] Roll Skia from 279b17fe9fc1 to d625048c853a (12 revisions) (flutter/flutter#187483) 2026-06-03 [email protected] [SwiftPM] Fix prefer_initializing_formals lint (flutter/flutter#187502) 2026-06-03 [email protected] Roll Fuchsia Linux SDK from q27k7_um1GvVrySZS... to ap7MhLX4TdpWRrLS_... (flutter/flutter#187478) 2026-06-03 [email protected] [SwiftPM] Fix concurrent directory/file/symlink creation crashes (flutter/flutter#186953) 2026-06-03 [email protected] [Impeller] Fix positioning of text shadow masks (flutter/flutter#187460) 2026-06-02 [email protected] Remove Material imports from painting tests (flutter/flutter#186937) 2026-06-02 [email protected] Add android_hardware_smoke_test integration tests (flutter/flutter#187130) 2026-06-02 [email protected] Roll pub packages (flutter/flutter#187471) 2026-06-02 [email protected] [flutter tool] propagate analytics env to sub-tools (flutter/flutter#186780) 2026-06-02 [email protected] Adds macro for fragment shaders to support flutter <= 3.44 (flutter/flutter#187316) 2026-06-02 [email protected] Small clean-up in different java files under `engine/src/flutter/shell/platform/android/io/flutter/embedding/engine/` (flutter/flutter#186631) 2026-06-02 [email protected] refactor(web): Unify ui.Path code for CanvasKit and Skwasm (flutter/flutter#187331) 2026-06-02 [email protected] Roll Packages from f5d50ca to 818b310 (2 revisions) (flutter/flutter#187441) 2026-06-02 [email protected] Allow selecting multi-digit device options (flutter/flutter#186184) 2026-06-02 [email protected] Improve error message for type mismatch in Navigator.pop and maybePop. (flutter/flutter#186571) 2026-06-02 [email protected] Remove semantics_tester import from material_button_test.dart (flutter/flutter#184807) 2026-06-02 [email protected] [flutter_tools] Refactor hostPlatform to use Abi.current() (flutter/flutter#185369) 2026-06-02 [email protected] Clean up avoid_type_to_string suppressions (flutter/flutter#186869) 2026-06-02 [email protected] Update Flutter documentation links in flutter_console.bat (flutter/flutter#187354) 2026-06-02 [email protected] Revert "[Impeller] Allow attaching specific texture mip levels and slices" (flutter/flutter#187445) If this roll has caused a breakage, revert this CL and stop the roller using the controls here: https://autoroll.skia.org/r/flutter-packages Please CC [email protected],[email protected] on the revert to ensure that a human is aware of the problem. To file a bug in Packages: https://github.com/flutter/flutter/issues/new/choose To report a problem with the AutoRoller itself, please file a bug: https://issues.skia.org/issues/new?component=1389291&template=1850622 Documentation for the AutoRoller is here: https://skia.googlesource.com/buildbot/+doc/main/autoroll/README.md
creatorpiyush
pushed a commit
to creatorpiyush/packages
that referenced
this pull request
Jun 10, 2026
…lutter#11832) Manual roll requested by [email protected] flutter/flutter@701665b...2ba5420 2026-06-03 [email protected] Roll Packages from 818b310 to b11504f (8 revisions) (flutter/flutter#187511) 2026-06-03 [email protected] Add new file patterns for team-web labeler (flutter/flutter#187397) 2026-06-03 [email protected] Roll Skia from 279b17fe9fc1 to d625048c853a (12 revisions) (flutter/flutter#187483) 2026-06-03 [email protected] [SwiftPM] Fix prefer_initializing_formals lint (flutter/flutter#187502) 2026-06-03 [email protected] Roll Fuchsia Linux SDK from q27k7_um1GvVrySZS... to ap7MhLX4TdpWRrLS_... (flutter/flutter#187478) 2026-06-03 [email protected] [SwiftPM] Fix concurrent directory/file/symlink creation crashes (flutter/flutter#186953) 2026-06-03 [email protected] [Impeller] Fix positioning of text shadow masks (flutter/flutter#187460) 2026-06-02 [email protected] Remove Material imports from painting tests (flutter/flutter#186937) 2026-06-02 [email protected] Add android_hardware_smoke_test integration tests (flutter/flutter#187130) 2026-06-02 [email protected] Roll pub packages (flutter/flutter#187471) 2026-06-02 [email protected] [flutter tool] propagate analytics env to sub-tools (flutter/flutter#186780) 2026-06-02 [email protected] Adds macro for fragment shaders to support flutter <= 3.44 (flutter/flutter#187316) 2026-06-02 [email protected] Small clean-up in different java files under `engine/src/flutter/shell/platform/android/io/flutter/embedding/engine/` (flutter/flutter#186631) 2026-06-02 [email protected] refactor(web): Unify ui.Path code for CanvasKit and Skwasm (flutter/flutter#187331) 2026-06-02 [email protected] Roll Packages from f5d50ca to 818b310 (2 revisions) (flutter/flutter#187441) 2026-06-02 [email protected] Allow selecting multi-digit device options (flutter/flutter#186184) 2026-06-02 [email protected] Improve error message for type mismatch in Navigator.pop and maybePop. (flutter/flutter#186571) 2026-06-02 [email protected] Remove semantics_tester import from material_button_test.dart (flutter/flutter#184807) 2026-06-02 [email protected] [flutter_tools] Refactor hostPlatform to use Abi.current() (flutter/flutter#185369) 2026-06-02 [email protected] Clean up avoid_type_to_string suppressions (flutter/flutter#186869) 2026-06-02 [email protected] Update Flutter documentation links in flutter_console.bat (flutter/flutter#187354) 2026-06-02 [email protected] Revert "[Impeller] Allow attaching specific texture mip levels and slices" (flutter/flutter#187445) If this roll has caused a breakage, revert this CL and stop the roller using the controls here: https://autoroll.skia.org/r/flutter-packages Please CC [email protected],[email protected] on the revert to ensure that a human is aware of the problem. To file a bug in Packages: https://github.com/flutter/flutter/issues/new/choose To report a problem with the AutoRoller itself, please file a bug: https://issues.skia.org/issues/new?component=1389291&template=1850622 Documentation for the AutoRoller is here: https://skia.googlesource.com/buildbot/+doc/main/autoroll/README.md
via-guy
pushed a commit
to via-guy/flutter
that referenced
this pull request
Jun 26, 2026
flutter#186571) <!-- Thanks for filing a pull request! Reviewers are typically assigned within a week of filing a request. To learn more about code review, see our documentation on Tree Hygiene: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md --> **Context** Currently, if a developer opens a strongly-typed route (such as `showDialog<Null>`) but accidentally pops it with an incompatible value (like `Navigator.pop(context, "CANCEL")`). Because the generic types do not match, the Dart runtime instantly throws a cryptic native `TypeError` (e.g., `type 'String' is not a subtype of type 'Null'`) without any context about which route or widget caused it. **Changes** * Added a `_debugCheckCanConsumeResult` helper to `Route<T>` that proactively validates `result is T?`. * Intercepts `Navigator.pop`, `Navigator.maybePop`, before they modify the stack or lock the Navigator. * If a type mismatch occurs, it now throws a highly descriptive `FlutterError` that pinpoints the exact expected type, the provided type, and the specific `Route` object involved. * Added comprehensive tests to `navigator_test.dart` to verify this behavior for `pop` and `maybePop` using a real-world `showDialog` scenario. Fixes flutter#16987 ## Pre-launch Checklist - [x] I read the [Contributor Guide] and followed the process outlined there for submitting PRs. - [x] I read the [AI contribution guidelines] and understand my responsibilities, or I am not using AI tools. - [x] I read the [Tree Hygiene] wiki page, which explains my responsibilities. - [x] I read and followed the [Flutter Style Guide], including [Features we expect every widget to implement]. - [x] I signed the [CLA]. - [x] I listed at least one issue that this PR fixes in the description above. - [x] I updated/added relevant documentation (doc comments with `///`). - [x] I added new tests to check the change I am making, or this PR is [test-exempt]. - [ ] I followed the [breaking change policy] and added [Data Driven Fixes] where supported. - [x] All existing and new tests are passing. If you need help, consider asking for advice on the #hackers-new channel on [Discord]. If this change needs to override an active code freeze, provide a comment explaining why. The code freeze workflow can be overridden by code reviewers. See pinned issues for any active code freezes with guidance. **Note**: The Flutter team is currently trialing the use of [Gemini Code Assist for GitHub](https://developers.google.com/gemini-code-assist/docs/review-github-code). Comments from the `gemini-code-assist` bot should not be taken as authoritative feedback from the Flutter team. If you find its comments useful you can update your code accordingly, but if you are unsure or disagree with the feedback, please feel free to wait for a Flutter team member's review for guidance on which automated comments should be addressed. <!-- Links --> [Contributor Guide]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#overview [AI contribution guidelines]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#ai-contribution-guidelines [Tree Hygiene]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md [test-exempt]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#tests [Flutter Style Guide]: https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md [Features we expect every widget to implement]: https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md#features-we-expect-every-widget-to-implement [CLA]: https://cla.developers.google.com/ [flutter/tests]: https://github.com/flutter/tests [breaking change policy]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#handling-breaking-changes [Discord]: https://github.com/flutter/flutter/blob/main/docs/contributing/Chat.md [Data Driven Fixes]: https://github.com/flutter/flutter/blob/main/docs/contributing/Data-driven-Fixes.md --------- Co-authored-by: chunhtai <[email protected]> Co-authored-by: Victor Sanni <[email protected]>
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
6 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Context
Currently, if a developer opens a strongly-typed route (such as
showDialog<Null>) but accidentally pops it with an incompatible value (likeNavigator.pop(context, "CANCEL")). Because the generic types do not match, the Dart runtime instantly throws a cryptic nativeTypeError(e.g.,type 'String' is not a subtype of type 'Null') without any context about which route or widget caused it.Changes
_debugCheckCanConsumeResulthelper toRoute<T>that proactively validatesresult is T?.Navigator.pop,Navigator.maybePop, before they modify the stack or lock the Navigator.FlutterErrorthat pinpoints the exact expected type, the provided type, and the specificRouteobject involved.navigator_test.dartto verify this behavior forpopandmaybePopusing a real-worldshowDialogscenario.Fixes #16987
Pre-launch Checklist
///).If you need help, consider asking for advice on the #hackers-new channel on Discord.
If this change needs to override an active code freeze, provide a comment explaining why. The code freeze workflow can be overridden by code reviewers. See pinned issues for any active code freezes with guidance.
Note: The Flutter team is currently trialing the use of Gemini Code Assist for GitHub. Comments from the
gemini-code-assistbot should not be taken as authoritative feedback from the Flutter team. If you find its comments useful you can update your code accordingly, but if you are unsure or disagree with the feedback, please feel free to wait for a Flutter team member's review for guidance on which automated comments should be addressed.