Added hash_value_overflow rule

[kimdv]

This fixes #2108

I'm not good at all to reggex. So I got a a little help from a friend 😅

[jpsim]

Thanks for the PR @kimdv! Do you think we should be encouraging the use of Swift 4.2's modernized hashing instead?

This rule seems especially well suited to avoid using a regular expression to detect the use of +/* and instead using string matching.

For context, the heavy use of regular expressions in SwiftLint have been contributing to performance cliffs and false positives and I would like us to start weaning off of them.

[SwiftLintBot]

	59 Warnings
⚠️	This PR introduced a violation in Firefox: /Users/distiller/project/osscheck/Firefox/Account/KeyBundle.swift:141:10: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Firefox: /Users/distiller/project/osscheck/Firefox/Storage/Visit.swift:63:10: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Firefox: /Users/distiller/project/osscheck/Firefox/Storage/Visit.swift:97:19: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Firefox: /Users/distiller/project/osscheck/Firefox/Sync/State.swift:99:12: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Kickstarter: /Users/distiller/project/osscheck/Kickstarter/KsApi/GraphSchema.swift:21:10: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Kickstarter: /Users/distiller/project/osscheck/Kickstarter/KsApi/models/Category.swift:101:10: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Kickstarter: /Users/distiller/project/osscheck/Kickstarter/KsApi/models/Category.swift:140:10: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Kickstarter: /Users/distiller/project/osscheck/Kickstarter/KsApi/models/DiscoveryParams.swift:77:10: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Kickstarter: /Users/distiller/project/osscheck/Kickstarter/Library/Format.swift:326:15: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Kickstarter: /Users/distiller/project/osscheck/Kickstarter/Library/Format.swift:395:15: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Kickstarter: /Users/distiller/project/osscheck/Kickstarter/Library/RefTag.swift:219:10: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Moya: /Users/distiller/project/osscheck/Moya/Sources/Moya/Endpoint.swift:122:12: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in SourceKitten: /Users/distiller/project/osscheck/SourceKitten/Source/SourceKittenFramework/SourceDeclaration.swift:181:12: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in SourceKitten: /Users/distiller/project/osscheck/SourceKitten/Source/SourceKittenFramework/UID.swift:46:12: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Swift: /Users/distiller/project/osscheck/Swift/stdlib/private/StdlibUnittest/LifetimeTracked.swift:51:10: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Swift: /Users/distiller/project/osscheck/Swift/stdlib/private/StdlibUnittest/MinimalTypes.swift:142:10: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Swift: /Users/distiller/project/osscheck/Swift/stdlib/private/StdlibUnittest/MinimalTypes.swift:195:10: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Swift: /Users/distiller/project/osscheck/Swift/stdlib/private/StdlibUnittest/MinimalTypes.swift:253:10: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Swift: /Users/distiller/project/osscheck/Swift/stdlib/private/StdlibUnittest/MinimalTypes.swift:309:10: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Swift: /Users/distiller/project/osscheck/Swift/stdlib/private/StdlibUnittest/StdlibCoreExtras.swift:119:10: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Swift: /Users/distiller/project/osscheck/Swift/stdlib/private/StdlibUnittest/StringConvertible.swift:64:10: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Swift: /Users/distiller/project/osscheck/Swift/stdlib/public/core/AnyHashable.swift:238:10: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Swift: /Users/distiller/project/osscheck/Swift/stdlib/public/core/CompilerProtocols.swift:187:10: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Swift: /Users/distiller/project/osscheck/Swift/stdlib/public/core/Hashable.swift:109:3: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Swift: /Users/distiller/project/osscheck/Swift/stdlib/public/core/FloatingPoint.swift:1242:10: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Swift: /Users/distiller/project/osscheck/Swift/stdlib/public/core/NewtypeWrapper.swift:22:10: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Swift: /Users/distiller/project/osscheck/Swift/stdlib/public/core/KeyPath.swift:46:16: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Swift: /Users/distiller/project/osscheck/Swift/stdlib/public/core/UnicodeScalarProperties.swift:1275:12: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Swift: /Users/distiller/project/osscheck/Swift/stdlib/public/SDK/CoreFoundation/CoreFoundation.swift:17:10: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Swift: /Users/distiller/project/osscheck/Swift/stdlib/public/SDK/Foundation/AffineTransform.swift:279:12: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Swift: /Users/distiller/project/osscheck/Swift/stdlib/public/SDK/Foundation/Date.swift:145:12: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Swift: /Users/distiller/project/osscheck/Swift/stdlib/public/SDK/Foundation/CharacterSet.swift:52:17: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Swift: /Users/distiller/project/osscheck/Swift/stdlib/public/SDK/Foundation/CharacterSet.swift:754:12: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Swift: /Users/distiller/project/osscheck/Swift/stdlib/public/SDK/Foundation/DateComponents.swift:266:12: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Swift: /Users/distiller/project/osscheck/Swift/stdlib/public/SDK/Foundation/DateInterval.swift:158:12: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Swift: /Users/distiller/project/osscheck/Swift/stdlib/public/SDK/Foundation/Decimal.swift:180:12: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Swift: /Users/distiller/project/osscheck/Swift/stdlib/public/SDK/Foundation/Calendar.swift:902:12: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Swift: /Users/distiller/project/osscheck/Swift/stdlib/public/SDK/Foundation/IndexPath.swift:665:12: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Swift: /Users/distiller/project/osscheck/Swift/stdlib/public/SDK/Foundation/IndexSet.swift:140:12: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Swift: /Users/distiller/project/osscheck/Swift/stdlib/public/SDK/Foundation/Locale.swift:408:12: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Swift: /Users/distiller/project/osscheck/Swift/stdlib/public/SDK/Foundation/Notification.swift:42:12: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Swift: /Users/distiller/project/osscheck/Swift/stdlib/public/SDK/Foundation/Measurement.swift:39:12: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Swift: /Users/distiller/project/osscheck/Swift/stdlib/public/SDK/Foundation/Data.swift:1647:12: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Swift: /Users/distiller/project/osscheck/Swift/stdlib/public/SDK/Foundation/NSRange.swift:16:12: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Swift: /Users/distiller/project/osscheck/Swift/stdlib/public/SDK/Foundation/NSStringEncodings.swift:54:12: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Swift: /Users/distiller/project/osscheck/Swift/stdlib/public/SDK/Foundation/PersonNameComponents.swift:74:12: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Swift: /Users/distiller/project/osscheck/Swift/stdlib/public/SDK/Foundation/TimeZone.swift:199:12: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Swift: /Users/distiller/project/osscheck/Swift/stdlib/public/SDK/Foundation/URLComponents.swift:303:12: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Swift: /Users/distiller/project/osscheck/Swift/stdlib/public/SDK/Foundation/URLComponents.swift:415:12: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Swift: /Users/distiller/project/osscheck/Swift/stdlib/public/SDK/Foundation/NSError.swift:409:10: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Swift: /Users/distiller/project/osscheck/Swift/stdlib/public/SDK/Foundation/NSError.swift:484:3: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Swift: /Users/distiller/project/osscheck/Swift/stdlib/public/SDK/Foundation/NSError.swift:572:12: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Swift: /Users/distiller/project/osscheck/Swift/stdlib/public/SDK/Foundation/NSError.swift:1803:12: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Swift: /Users/distiller/project/osscheck/Swift/stdlib/public/SDK/Foundation/UUID.swift:77:12: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Swift: /Users/distiller/project/osscheck/Swift/stdlib/public/SDK/Foundation/URLRequest.swift:232:12: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Swift: /Users/distiller/project/osscheck/Swift/stdlib/public/SDK/Foundation/URL.swift:635:12: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in Swift: /Users/distiller/project/osscheck/Swift/stdlib/public/SDK/ObjectiveC/ObjectiveC.swift:219:10: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in WordPress: /Users/distiller/project/osscheck/WordPress/WordPress/Classes/Models/JetpackSiteRef.swift:26:5: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)
⚠️	This PR introduced a violation in WordPress: /Users/distiller/project/osscheck/WordPress/WordPressFlux/WordPressFlux/Sources/Dispatcher.swift:6:12: warning: Legacy Hashing Violation: Prefer using the hash(into:) function instead of overriding hashValue (legacy_hashing)

	12 Messages
📖	Linting Aerial with this PR took 2.07s vs 2.0s on master (3% slower)
📖	Linting Alamofire with this PR took 4.5s vs 4.25s on master (5% slower)
📖	Linting Firefox with this PR took 17.18s vs 15.89s on master (8% slower)
📖	Linting Kickstarter with this PR took 27.25s vs 23.32s on master (16% slower)
📖	Linting Moya with this PR took 2.46s vs 2.28s on master (7% slower)
📖	Linting Nimble with this PR took 2.55s vs 2.12s on master (20% slower)
📖	Linting Quick with this PR took 0.73s vs 0.66s on master (10% slower)
📖	Linting Realm with this PR took 4.71s vs 4.14s on master (13% slower)
📖	Linting SourceKitten with this PR took 1.58s vs 1.33s on master (18% slower)
📖	Linting Sourcery with this PR took 6.21s vs 5.6s on master (10% slower)
📖	Linting Swift with this PR took 38.24s vs 32.97s on master (15% slower)
📖	Linting WordPress with this PR took 28.87s vs 23.8s on master (21% slower)

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[kimdv]

Thanks, @jpsim!

We could do that, but I have just finished a project where we needed custom hashes.

I have seen your comments lately on avoiding regular expression, so I really would like to remove the hash regular expression, so can you point where I could look for an example?

[marcelofabri]

@kimdv I think @jpsim's suggestion was to use the new func hash(into hasher: inout Hasher) instead of manually combining hashes:

extension GridPoint: Hashable {
  func hash(into hasher: inout Hasher) {
    hasher.combine(x)
    hasher.combine(y)
  }
}

(from https://github.com/apple/swift-evolution/blob/master/proposals/0206-hashable-enhancements.md#the-hashinto-requirement)

[kimdv]

Sure we can do that!
Will make it min requirement Swift 4.2, what do you think?

@marcelofabri can you maybe point out where to look for inspiration to avoid regular expression?

[marcelofabri]

@kimdv sounds good for min requirement.

If the rule is updated to validate that hash(into:) should be used (instead of checking for overflow values), it becomes easier. You can implement ASTRule and check for hashValue computed properties declarations instead of using regexes. ProhibitedInterfaceBuilderRule seems a good place to start. WeakDelegateRule has a check for computed variables, which will be needed as well.

[kimdv]

Thanks @marcelofabri!

The rule got much simpler 🚀
I think i have got something right here :)

[kimdv]

@marcelofabri it seems that the tests that are failing is Swiftlint itself.

Should i fix those places in Swiftlint where it violates the rule?

[marcelofabri]

@kimdv Please do it!

[kimdv]

Pushed changes and stuff starts to pass now! 🚀

[marcelofabri]

@kimdv Thanks for this - just had some minor comments but overall it looks great!

We also need a changelog entry for this change ✨

[kimdv]

@marcelofabri I rebased with master (Don't know if I did it right) and added your feedback and added changelog entry

[kimdv]

@jpsim should be resolved now 🚀

[jpsim]

Should we name this rule "Legacy Hashing" to align with the other legacy family of rules?

• Legacy CGGeometry Functions
• Legacy Constant
• Legacy Constructor
• Legacy NSGeometry Functions
• Legacy Random

[jpsim]

Merged! 🎉

Thanks @kimdv !