Show error message in release mode when box is not laid out without losing performance #126302
Conversation
| @@ -1985,7 +1985,7 @@ abstract class RenderBox extends RenderObject { | |||
| } | |||
| return true; | |||
| }()); | |||
| return _size!; | |||
| return _size ?? (throw AssertionError('RenderBox was not laid out: $this')); | |||
There was a problem hiding this comment.
we should use StateError in release builds, not AssertionError, and we should definitely not call RenderBox.toString, because merely referencing that has significant performance implications.
There was a problem hiding this comment.
- StateError fixed
- we should definitely not call RenderBox.toString: May I know a bit more details - do you mean code size or runtime overhead? For code size, I guess toString is not tree-stripped since there can be
dynamic.toStringbut I will make an experiment; for runtime overhead, IMHO the whole error processing logic is quite complex and slow, thus no need to worry
There was a problem hiding this comment.
Hmm I realize in release mode, toString() calls toStringShort and then it outputs almost nothing (just describeIdentity)... Then let me just change to that, thus also avoiding toString
|
test-exempt: changes the type of a release mode exception |
|
(Possibly related: dart-lang/sdk#52317) |
|
(GitHub says there is update 1 hour ago but I cannot see anything new... GitHub looks a bit weird today... So if I am missing something just tell me!)
|
|
It looks like this pull request may not have tests. Please make sure to add tests before merging. If you need an exemption to this rule, contact Hixie on the #hackers channel in Chat (don't just cc him here, he won't see it! He's on Discord!). If you are not sure if you need tests, consider this rule of thumb: the purpose of a test is to make sure someone doesn't accidentally revert the fix. Ask yourself, is there anything in your PR that you feel it is important we not accidentally revert back to how it was before your fix? Reviewers: Read the Tree Hygiene page and make sure this patch meets those guidelines before LGTMing. |
|
@fzyzcjy I seem to remember that this was opened in the context of Crashlytics garbling up some stack traces. Without that issue, is this PR still relevant and useful? |
| @@ -1985,7 +1985,7 @@ abstract class RenderBox extends RenderObject { | |||
| } | |||
| return true; | |||
| }()); | |||
| return _size!; | |||
| return _size ?? (throw StateError('RenderBox was not laid out: $runtimeType#${shortHash(this)}')); | |||
There was a problem hiding this comment.
We avoid calling toString on runtimeType (as is done here implicitly) in release mode, see objectRuntimeType
There was a problem hiding this comment.
I did it deliberately ;) This is because objectRuntimeType will yield <optimized out> at runtime, while the main idea of the PR is to know which exact class causes the bug.
Given the godbolt decompile results above, it seems that, as long as we do not touch this branch (i.e. throw error), we have zero overhead. When we throw error, we already have a ton of overhead and trouble so this runtimeType.toString does not seem to be a big problem.
Yes and no. Yes I opened a series of issues because of Sentry yields wrong stacks. However, for this single one, I guess this can still be useful even not under that scenario, because the Since this PR does not cause performance problems (see Godbolt above), I guess this will help devs. |
…ithout losing performance (flutter/flutter#126302)
…ithout losing performance (flutter/flutter#126302)
…ithout losing performance (flutter/flutter#126302)
Roll Flutter from 0b74153 to 8a5c22e (46 revisions) flutter/flutter@0b74153...8a5c22e 2023-06-07 [email protected] Super tiny MediaQuery doc update (flutter/flutter#127904) 2023-06-07 [email protected] Revert "Make inspector weakly referencing the inspected objects." (flutter/flutter#128436) 2023-06-07 [email protected] Update menu API docs to help developers migrate to m3 (flutter/flutter#128351) 2023-06-07 [email protected] [tools] allow explicitly specifying the JDK to use via a new config setting (flutter/flutter#128264) 2023-06-07 [email protected] Roll Flutter Engine from 6f9df0f988c1 to 59d5444cf06c (3 revisions) (flutter/flutter#128376) 2023-06-07 [email protected] Do not try to load main/default asset image if only higher-res variants exist (flutter/flutter#128143) 2023-06-07 [email protected] Addressed Ambiguity in transform.scale constructor docs (flutter/flutter#128182) 2023-06-07 [email protected] Super tiny fix of dead link (flutter/flutter#128160) 2023-06-07 [email protected] Refactor tests (flutter/flutter#128371) 2023-06-07 [email protected] Make inspector weakly referencing the inspected objects. (flutter/flutter#128095) 2023-06-07 [email protected] Add viewId to PointerEvents (flutter/flutter#128287) 2023-06-07 [email protected] Show error message in release mode when box is not laid out without losing performance (flutter/flutter#126302) 2023-06-06 [email protected] Roll Flutter Engine from ca499463ec2e to 6f9df0f988c1 (1 revision) (flutter/flutter#128363) 2023-06-06 [email protected] Update Draggable YouTube video link (flutter/flutter#128078) 2023-06-06 [email protected] Remove more rounding hacks from TextPainter (flutter/flutter#127826) 2023-06-06 [email protected] Roll Flutter Engine from 4571695f9e76 to ca499463ec2e (1 revision) (flutter/flutter#128356) 2023-06-06 [email protected] [Android] Update plugin and module templates to use Flutter constant for `compileSdkVersion` (flutter/flutter#128073) 2023-06-06 [email protected] handleSelectWord in MultiSelectableSelectionContainerDelegate should handle rects inside of rects (flutter/flutter#127478) 2023-06-06 [email protected] [flutter_tools] never tree shake 0x20 (space) font codepoints on web (flutter/flutter#128302) 2023-06-06 [email protected] Remove `textScaleFactor` dependent logic from `AppBar` (flutter/flutter#128112) 2023-06-06 [email protected] Roll Flutter Engine from b6d37f8f74ad to 4571695f9e76 (6 revisions) (flutter/flutter#128350) 2023-06-06 [email protected] Fix `Null check operator used on a null value` on TextField with contextMenuBuilder (flutter/flutter#128114) 2023-06-06 [email protected] Roll Packages from db4e5c2 to da72219 (10 revisions) (flutter/flutter#128348) 2023-06-06 [email protected] Updating cirrus docker image to ubuntu focal. (flutter/flutter#128291) 2023-06-06 [email protected] Adding example for migrating to navigation drawer (flutter/flutter#128295) 2023-06-06 [email protected] Roll Flutter Engine from 722aad83e5fe to b6d37f8f74ad (2 revisions) (flutter/flutter#128341) 2023-06-06 [email protected] Clean-up viewId casts in flutter_test (flutter/flutter#128256) 2023-06-06 [email protected] Update cherry-pick issue template to more uniform labels. (flutter/flutter#128333) 2023-06-06 [email protected] Use Material3 in the 2D viewport tests (flutter/flutter#128155) 2023-06-06 [email protected] Use a `show` over a `hide` for `test_api` exports (flutter/flutter#128298) 2023-06-06 [email protected] Roll Flutter Engine from aaa7574375a6 to 722aad83e5fe (1 revision) (flutter/flutter#128307) 2023-06-06 [email protected] Migration guide for moving from BottomNavigationBar to NavigationBar (flutter/flutter#128263) 2023-06-06 [email protected] [web] Use 'Uri' instead of 'dart:html' to extract pathname (flutter/flutter#127983) 2023-06-06 [email protected] Roll Flutter Engine from 2b353ae90731 to aaa7574375a6 (4 revisions) (flutter/flutter#128301) 2023-06-05 [email protected] Roll Flutter Engine from 220ece4d9faa to 2b353ae90731 (1 revision) (flutter/flutter#128293) 2023-06-05 49699333+dependabot[bot]@users.noreply.github.com Bump actions/labeler from 4.0.4 to 4.1.0 (flutter/flutter#128290) 2023-06-05 [email protected] Roll Flutter Engine from 7f12e3497428 to 220ece4d9faa (6 revisions) (flutter/flutter#128282) 2023-06-05 [email protected] [framework] attempt non-key solution (flutter/flutter#128273) 2023-06-05 [email protected] [labeler] Fix adding labels when name is directory (flutter/flutter#128243) 2023-06-05 [email protected] Remove scrollbar deprecations isAlwaysShown and hoverThickness (flutter/flutter#127351) 2023-06-05 [email protected] Fix update drag error that made NestedScrollView un-scrollable (flutter/flutter#127718) 2023-06-05 [email protected] Roll Flutter Engine from f9f72388a4da to 7f12e3497428 (4 revisions) (flutter/flutter#128271) 2023-06-05 [email protected] Migrate SemanticsBinding to onSemanticsActionEvent (flutter/flutter#128254) 2023-06-05 [email protected] Roll Flutter Engine from c838a1b05924 to f9f72388a4da (19 revisions) (flutter/flutter#128252) 2023-06-05 [email protected] [framework] force flexible space background to rebuild. (flutter/flutter#128138) 2023-06-05 [email protected] Roll Packages from 75085ed to db4e5c2 (4 revisions) (flutter/flutter#128246) ...
…ithout losing performance (flutter/flutter#126302)
…ithout losing performance (flutter/flutter#126302)
…ithout losing performance (flutter/flutter#126302)
…ithout losing performance (flutter/flutter#126302)
Close #126303
When I encounter bugs in production environment saying null pointer error on
return _size!, I wish I could know more information! However, currently the information is revealed byassert(hasSize, 'RenderBox was not laid out: $this');, thus only in debug mode can I know what isthis(and/or more information that can be added), while in release mode I can only see a stack trace saying it isRenderBox.sizethat throws - nothing more :/Therefore, it is intuitive to add this extra information in release mode. However, will it affect performance? We all know this is in critical path and should be quite careful. Thus I did some experiments: https://godbolt.org/z/zPPPf5969 From my naive understanding of assembly, the two versions of code (
size!vssize ?? throw) has the same assembly, except that they throw different types of errors. In other words, when there is no error, both code should be equivalent; when there is an error, surely the new code will be slower since it callsthis.toString(), but the error handling process is rare and already heavy, so this is not a problem.Pre-launch Checklist
///).If you need help, consider asking for advice on the #hackers-new channel on Discord.