[iOS] option to enable suggestions with autocorrect off

[jan-swiezynski]

There is no possibility on iOS to leave the auto-suggest bar visible and have the autocorrection turned off when showing TextField. Tapping outside TextField with autocorrection on fills the TextField with suggestion and it's not always an intended behaviour.

Fixes flutter/flutter#159584

Removed 1 Test.

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[chinmaygarde]

cc @cbracken

[cbracken]

I've left style/testing comments inline, but at a much higher level, I'm not entirely whether enableSuggestions is the right approach here.

EditableText widgets have a spellCheckConfiguration property that holds a SpellCheckConfiguration. I would have assumed that passing SpellCheckConfiguration.disabled would be the way to do this.

@justinmc will know the answer to that question.

[cbracken]

A few notes:

• In Objective-C we should be using BOOL, not bool. In this case, the surrounding code is unfortunately already using C++ bool. I'll send a separate cleanup patch.
• The Dart side API for this is enableSuggestions, for readability, please deal with this settings in terms of enableSuggestions in the Obj-C code. See the style guide rationale for why. Again, the surrounding code violates this and I'll send a separate patch to clean it up.

Something like this works:

NSString* enableSuggestionsValue = configuration[kEnableSuggestions];
BOOL enableSuggestions = enabledSuggestionsValue ? enableSuggestionsValue.boolValue : YES;

[cbracken]

The existing code was landed by @bleroux in #46144 to fix flutter/flutter#134881. Updating this behaviour will be a minor regression to users who were relying on disabling autocorrect to disable spelling suggestions, but that seems reasonable since this adds a new finer-grained mechanism to opt out.

The enableSuggestions API docs currently state that this flag only affects Android. @bleroux do you know the background on why we don't apply it to iOS as well?

If we change this behaviour, we will definitely need to update the framework side API documentation to reflect this and point to Apple's UITextSpellCheckingType docs.

[bleroux]

The enableSuggestions API docs currently state that this flag only affects Android. @bleroux do you know the background on why we don't apply it to iOS as well?

I don't know the background. The documentation landed in flutter/flutter#42550. It seems that this was implemented to match an Android feature. Maybe something similar did not exist on the iOS side at that time?

[justinmc]

My guess is that it wasn't possible to control these independently at the time that Flutter's enableSuggestions was added. Are we sure that's not still true? +1 to updating the docs if this change lands.

[cbracken]

Please don't delete tests for existing behaviour; they were added for a reason.

You'll need to update the existing test to reflect the new expected behaviour and add additional testing to cover all four combinations of autocorrect/enableSuggestions.

[justinmc]

To be clear on iOS these are the three features we're talking about here:

Spell check	Suggestions	Autocorrect
Red underline, red highlight, and suggestion dialog for misspelled words.	Completion suggestions that appear above the software keyboard as the user types. If a hardware keyboard is used instead, there is a blue highlight and a suggestion dialog.	Automatic replacement of common typos.
Disabled by default, enable with spellCheckConfiguration: SpellCheckConfiguration().	Enabled by default, disable with autocorrect: false. After this PR, would instead be disabled with enableSuggestions: false.	Enabled by default, disable with autocorrect: false.

So suggestions and autocorrect are controlled by the same flag, and this PR wants to be able to control them independently? @jan-swiezynski Can you confirm that your understanding is the same as mine and that this PR has the desired effect?

[justinmc]

My guess is that it wasn't possible to control these independently at the time that Flutter's enableSuggestions was added. Are we sure that's not still true? +1 to updating the docs if this change lands.

[jan-swiezynski]

@justinmc Yes, exactly. The change separates autocorrect from suggestions displays and allows presenting suggestions but with autocorrect feature disabled.

[justinmc]

I checked out this branch locally and it fixes the intended bug, but it's not possible to hide suggestions while enabling autocorrect! Is it possible to fix that as well?

autocorrect	enableSuggestions	spellCheckConfiguration	This PR
false	false	SpellCheckConfiguration.disabled()	✅
false	false	SpellCheckConfiguration()	✅
false	true	SpellCheckConfiguration.disabled()	✅
false	true	SpellCheckConfiguration()	✅
true	false	SpellCheckConfiguration.disabled()	❌ Suggestions appear but should not.
true	false	SpellCheckConfiguration()	❌ Suggestions appear but should not.
true	true	SpellCheckConfiguration.disabled()	✅
true	true	SpellCheckConfiguration()	✅

Edit: This is broken on the main branch as well, so I'm ok with considering this a separate issue if it's not a trivial fix.

[cbracken]

Hi @jan-swiezynski is this still on your radar?

[jan-swiezynski]

Hi @jan-swiezynski is this still on your radar?

Yes, I'll get back to it in few days.