Added identical(a,b) short circuit to Material Library lerp methods #120829
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| if (identical(a, b)) { | ||
| return a; | ||
| } |
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There's a slight change of functionality here. Previously this would always return a MenuBarThemeData and never null (although it has a nullable return type). Now, it will return null if a and b both are null. Not sure if this matters...
(This is also true for a lot of other lerp methods adjusted in this PR, I am gonna refrain from commenting on all of them :))
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(Unrelated to this PR:) It is driving me crazy how inconsistent the lerp methods are with regards to nullability. Some allow nulls as a arguments, some don't. Some allow null as a return value, some don't. I wonder if we should audit this and standardize on one thing (or maybe its already too late to do this).
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I've added my notes about the variation in lerp methods to the PR's description.
The slight change in MenuBarThemeData.lerp() was intentional because the code was rather new (so new it still referred to its themes as "text buttons") so it seemed like it would be safe to normalize it a little.
Similar changes were only applied to lerp methods that already special-cased (a == null && b == null). For the others (the ones without this special case) the translation was:
if (identical(a, b) && a != null) {
return a;
}
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Sounds good. Thanks for adding the stats to the PR description.
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* 3ad7ea3 Roll Plugins from 9c312d4d2f5f to 2ce625f1a87e (5 revisions) (flutter/flutter#120793) * 7865713 Roll Flutter Engine from 1328c4bc6299 to 4db9673d48d6 (2 revisions) (flutter/flutter#120796) * 541a8bf Fix switching from scrollable and non-scrollable tab bars throws (flutter/flutter#120771) * ab1390e Use black30 for CupertinoTabBar's border (flutter/flutter#119509) * a513d4e Fix `flutter_localizations` README references (flutter/flutter#120800) * a664f08 In test of --(no-)fatal-infos analyzer flags, pin missing_return to info (flutter/flutter#120797) * ef49f56 Add Android unit tests to plugin template (flutter/flutter#120720) * a12e242 Improve CupertinoContextMenu to match native more (flutter/flutter#117698) * a9f4366 Fix the `flutter run -d linux` tests (flutter/flutter#120721) * dff0955 09da59a5a Roll Dart SDK from c022d475e9d8 to 5d17a336bdfe (1 revision) (flutter/engine#39649) (flutter/flutter#120816) * f35de0c Adds wide gamut saveLayer integration test (flutter/flutter#120131) * 99dcaa2 Roll Flutter Engine from 09da59a5adcf to a8b3d1af55b6 (3 revisions) (flutter/flutter#120821) * 8d15083 Use the impellerc GLES output flag when compiling shaders for Android (flutter/flutter#120647) * c6b636f [flutter_tools] Replace Future.catchError() with Future.then(onError: ...) (flutter/flutter#120637) * 2b7d709 Add `@widgetFactory` annotation (flutter/flutter#117455) * e65dfba Add Linux unit tests to plugin template (flutter/flutter#120814) * dccec41 5de007b90 Remove "bringup: true" from "Linux Fuchsia FEMU" (flutter/engine#39651) (flutter/flutter#120826) * d6de6bc 9f3b061b7 Roll buildroot to 64b0c3deecaff8e66c2deb74e2171e8297b2bfcd (flutter/engine#39653) (flutter/flutter#120830) * da2508c bb1ff84b6 Add a white background to app anatomy diagram (flutter/engine#39638) (flutter/flutter#120832) * 1f85497 [flutter_tools] Add the NoProfile parameter to the PowerShell execution statement (flutter/flutter#120786) * 4ad47fb Fix `StretchingOverscrollIndicator` not handling directional changes correctly (flutter/flutter#116548) * 9a721c4 Update AndroidManifest.xml.tmpl (flutter/flutter#120527) * c0b7d2d Roll Flutter Engine from bb1ff84b6c4f to 02a379db1d38 (4 revisions) (flutter/flutter#120845) * a10e295 Added identical(a,b) short circuit to Material Library lerp methods (flutter/flutter#120829) * efde350 Roll Flutter Engine from 02a379db1d38 to a966cf878ffd (2 revisions) (flutter/flutter#120846) * cc473e4 Roll Flutter Engine from a966cf878ffd to 3fc40ca5beb9 (3 revisions) (flutter/flutter#120850) * d125242 Roll Flutter Engine from 3fc40ca5beb9 to 9fa2a5c3cfbd (2 revisions) (flutter/flutter#120856) * 22e17bb ea1d087c4 Roll Skia from b8b36146c7a0 to 7b3fb04bc3d4 (3 revisions) (flutter/engine#39673) (flutter/flutter#120860) * f85438b c8b1d2ffa Roll Fuchsia Mac SDK from YpQKlqmyn8r_snx06... to xl9Y8o-9FDyvPogki... (flutter/engine#39675) (flutter/flutter#120887) * 174a562 d699b4a91 Roll Flutter from e3471f0 to df41e58 (83 revisions) (flutter/plugins#7184) (flutter/flutter#120888) * 170539f Roll Flutter Engine from c8b1d2ffaec8 to 0d8d93306822 (2 revisions) (flutter/flutter#120891)
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* 3ad7ea3c9 Roll Plugins from 9c312d4 to 2ce625f (5 revisions) (flutter/flutter#120793) * 786571368 Roll Flutter Engine from 1328c4bc6299 to 4db9673d48d6 (2 revisions) (flutter/flutter#120796) * 541a8bfd9 Fix switching from scrollable and non-scrollable tab bars throws (flutter/flutter#120771) * ab1390e0a Use black30 for CupertinoTabBar's border (flutter/flutter#119509) * a513d4e7b Fix `flutter_localizations` README references (flutter/flutter#120800) * a664f08a5 In test of --(no-)fatal-infos analyzer flags, pin missing_return to info (flutter/flutter#120797) * ef49f5661 Add Android unit tests to plugin template (flutter/flutter#120720) * a12e242c0 Improve CupertinoContextMenu to match native more (flutter/flutter#117698) * a9f43665c Fix the `flutter run -d linux` tests (flutter/flutter#120721) * dff09558d 09da59a5a Roll Dart SDK from c022d475e9d8 to 5d17a336bdfe (1 revision) (flutter/engine#39649) (flutter/flutter#120816) * f35de0c80 Adds wide gamut saveLayer integration test (flutter/flutter#120131) * 99dcaa2d9 Roll Flutter Engine from 09da59a5adcf to a8b3d1af55b6 (3 revisions) (flutter/flutter#120821) * 8d150833b Use the impellerc GLES output flag when compiling shaders for Android (flutter/flutter#120647) * c6b636fa5 [flutter_tools] Replace Future.catchError() with Future.then(onError: ...) (flutter/flutter#120637) * 2b7d709fd Add `@widgetFactory` annotation (flutter/flutter#117455) * e65dfba8e Add Linux unit tests to plugin template (flutter/flutter#120814) * dccec41d5 5de007b90 Remove "bringup: true" from "Linux Fuchsia FEMU" (flutter/engine#39651) (flutter/flutter#120826) * d6de6bc68 9f3b061b7 Roll buildroot to 64b0c3deecaff8e66c2deb74e2171e8297b2bfcd (flutter/engine#39653) (flutter/flutter#120830) * da2508c9f bb1ff84b6 Add a white background to app anatomy diagram (flutter/engine#39638) (flutter/flutter#120832) * 1f85497ef [flutter_tools] Add the NoProfile parameter to the PowerShell execution statement (flutter/flutter#120786) * 4ad47fb47 Fix `StretchingOverscrollIndicator` not handling directional changes correctly (flutter/flutter#116548) * 9a721c456 Update AndroidManifest.xml.tmpl (flutter/flutter#120527) * c0b7d2ddd Roll Flutter Engine from bb1ff84b6c4f to 02a379db1d38 (4 revisions) (flutter/flutter#120845) * a10e295a0 Added identical(a,b) short circuit to Material Library lerp methods (flutter/flutter#120829) * efde35081 Roll Flutter Engine from 02a379db1d38 to a966cf878ffd (2 revisions) (flutter/flutter#120846) * cc473e4f1 Roll Flutter Engine from a966cf878ffd to 3fc40ca5beb9 (3 revisions) (flutter/flutter#120850) * d1252428c Roll Flutter Engine from 3fc40ca5beb9 to 9fa2a5c3cfbd (2 revisions) (flutter/flutter#120856) * 22e17bb71 ea1d087c4 Roll Skia from b8b36146c7a0 to 7b3fb04bc3d4 (3 revisions) (flutter/engine#39673) (flutter/flutter#120860)
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…r#7186) * 3ad7ea3c9 Roll Plugins from 9c312d4 to 2ce625f (5 revisions) (flutter/flutter#120793) * 786571368 Roll Flutter Engine from 1328c4bc6299 to 4db9673d48d6 (2 revisions) (flutter/flutter#120796) * 541a8bfd9 Fix switching from scrollable and non-scrollable tab bars throws (flutter/flutter#120771) * ab1390e0a Use black30 for CupertinoTabBar's border (flutter/flutter#119509) * a513d4e7b Fix `flutter_localizations` README references (flutter/flutter#120800) * a664f08a5 In test of --(no-)fatal-infos analyzer flags, pin missing_return to info (flutter/flutter#120797) * ef49f5661 Add Android unit tests to plugin template (flutter/flutter#120720) * a12e242c0 Improve CupertinoContextMenu to match native more (flutter/flutter#117698) * a9f43665c Fix the `flutter run -d linux` tests (flutter/flutter#120721) * dff09558d 09da59a5a Roll Dart SDK from c022d475e9d8 to 5d17a336bdfe (1 revision) (flutter/engine#39649) (flutter/flutter#120816) * f35de0c80 Adds wide gamut saveLayer integration test (flutter/flutter#120131) * 99dcaa2d9 Roll Flutter Engine from 09da59a5adcf to a8b3d1af55b6 (3 revisions) (flutter/flutter#120821) * 8d150833b Use the impellerc GLES output flag when compiling shaders for Android (flutter/flutter#120647) * c6b636fa5 [flutter_tools] Replace Future.catchError() with Future.then(onError: ...) (flutter/flutter#120637) * 2b7d709fd Add `@widgetFactory` annotation (flutter/flutter#117455) * e65dfba8e Add Linux unit tests to plugin template (flutter/flutter#120814) * dccec41d5 5de007b90 Remove "bringup: true" from "Linux Fuchsia FEMU" (flutter/engine#39651) (flutter/flutter#120826) * d6de6bc68 9f3b061b7 Roll buildroot to 64b0c3deecaff8e66c2deb74e2171e8297b2bfcd (flutter/engine#39653) (flutter/flutter#120830) * da2508c9f bb1ff84b6 Add a white background to app anatomy diagram (flutter/engine#39638) (flutter/flutter#120832) * 1f85497ef [flutter_tools] Add the NoProfile parameter to the PowerShell execution statement (flutter/flutter#120786) * 4ad47fb47 Fix `StretchingOverscrollIndicator` not handling directional changes correctly (flutter/flutter#116548) * 9a721c456 Update AndroidManifest.xml.tmpl (flutter/flutter#120527) * c0b7d2ddd Roll Flutter Engine from bb1ff84b6c4f to 02a379db1d38 (4 revisions) (flutter/flutter#120845) * a10e295a0 Added identical(a,b) short circuit to Material Library lerp methods (flutter/flutter#120829) * efde35081 Roll Flutter Engine from 02a379db1d38 to a966cf878ffd (2 revisions) (flutter/flutter#120846) * cc473e4f1 Roll Flutter Engine from a966cf878ffd to 3fc40ca5beb9 (3 revisions) (flutter/flutter#120850) * d1252428c Roll Flutter Engine from 3fc40ca5beb9 to 9fa2a5c3cfbd (2 revisions) (flutter/flutter#120856) * 22e17bb71 ea1d087c4 Roll Skia from b8b36146c7a0 to 7b3fb04bc3d4 (3 revisions) (flutter/engine#39673) (flutter/flutter#120860)
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Handle a common case in
Foo.lerp(a, b, t): if a and b are identical, then just return a. This avoids needlessly constructing a newFooand recursively lerping all of its properties. If a and b refer to the same const object, then we also preserve their singleton identity.In the Material library, ThemeData's properties are legion and by default they are const values. The most common application of ThemeData.lerp, animating between light and dark themes, only really affects the colorScheme property. The rest of the properties are needlessly recreated by recursively applying lerping each of their own properties. And in doing so, the singleton values they're bound to and the low cost of comparing them for equality, is lost. That's a significant amount of needless churn.
The trivial changes applied in this PR aim to short-circuit the work at the ThemeData property level.
Some random observations about ~50
Foo.lerp(Foo? a, Foo? b, double t)methods that were updated here:Foorather thanFoo?, even though their parameters are nullable. The rest include a special case that returns null forFoo.lerp(null, null, t).Foo()when both a and b are null. An additional special case could returnconst Foo(), but that didn't seem to be worth the trouble.AppBarTheme.lerp(null, null)is the one exception. It does not returnAppBarTheme()it has two IconThemeData properties andIconThemeData.lerp(null, null)returns a new IconThemeData.static BorderSide lerp(BorderSide a, BorderSide b, double t). Most of the work-arounds are similar but not equivalent, see for example TimePickerThemeData.lerp, _lerpSides in checkbox_theme.dart, _lerpBorderSide in date_picker_theme.dart, _lerpSides in chip_theme.dart./// The argument `t` must not be null.