[webkit-dev] Coding style change proposal: Avoid using Objective C autorelease when possible

[Jean-Yves Avenard]

+1

There’s quite a few of those, I’ve removed some when I encountered them, some of them not so trivial replacement due to local scoping. 

Jean-Yves

Sent from my iPhone

> On 5 Apr 2025, at 11:45 am, Chris Dumez via webkit-dev <webkit-dev at lists.webkit.org> wrote:
> 
> Hi,
> 
> I would like to propose updating the WebKit coding style to recommend avoiding autorelease in Objective C whenever possible, for the following reasons:
> - Performance reasons:
>   - Cleaning up objects from all over the memory space in an autorelease pool can be slow and can cause memory spikes.
> - Memory Safety:
>   - Holding a RetainPtr to the object makes lifetime clearer, whereas autorelease pool draining is not as clear and can result in use-after-free bugs.
> - Easier debugging:
>   - Memory corruption bugs are harder to debug when it happens during autorelease pool drain.
> 
> Concretely, this means writing code like this:
> ```
> RetainPtr extensionDatabaseQueueName = adoptNS([[NSString alloc] initWithFormat:@"com.apple.WebKit.WKWebExtensionSQLiteStore.%@", _uniqueIdentifier]); 
> String foo = “foo”_s;
> [object callWith:foo.createNSString().get()];
> URL foo = “https://www.webkit.org”_s;
> [object callWith:foo.createNSURL().get()];
> ```
> Instead of:
> ```
> NSString *extensionDatabaseQueueName = [NSString stringWithFormat:@"com.apple.WebKit.WKWebExtensionSQLiteStore.%@", _uniqueIdentifier];
> RetainPtr extensionDatabaseQueueName = [NSString stringWithFormat:@"com.apple.WebKit.WKWebExtensionSQLiteStore.%@", _uniqueIdentifier];
> String foo = “foo”_s;
> [object callWith:(NSString *)foo]; // This does autorelease internally.
> URL foo = “https://www.webkit.org”_s;
> [object callWith:(NSURL *)foo]; // This does autorelease internally.
> ```
> 
> Example PR: https://github.com/WebKit/WebKit/pull/43656
> 
> What do you think?
> 
> Thanks,
> Chris Dumez.
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> webkit-dev at lists.webkit.org
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