2.0.0

This is a major release. The single NerdzUtils module is split into four products behind a
compatibility umbrella, the standalone NerdzDate package is folded in, CocoaPods support is
removed, and thirteen defects are fixed. Several of those fixes change observable behavior, so
read Behavior changes before upgrading.

Breaking changes

• The package now vends NerdzCore, NerdzDate, NerdzUIKit, NerdzKeychain and the
  NerdzUtils umbrella. import NerdzUtils keeps working because the umbrella re-exports all
  four, so existing code compiles unchanged. New code should depend on the specific products.
• The standalone NerdzDate package is discontinued and lives here as the NerdzDate product. Its
  consumers change the package URL. A consumer cannot depend on both the old package and this one
  at the same time, because Swift Package Manager rejects two packages vending the same product
  name in one graph.
• UIColor.init(hex:alpha:) is now failable and its alpha parameter is optional:
  init?(hex: String, alpha: CGFloat? = nil). Use UIColor.hex(_:alpha:fallback:) for the
  non optional path.
• JSONDecoder.DataDecodingStrategy no longer conforms to NZExtensionCompatible. It declared no
  members, so its .nz namespace was empty, and the conformance prevented downstream code from
  declaring its own.
• AtomicAsyncOperation.Action's finish closure, UIViewController.nz.easilyAddChild's
  configurationAction, the WindowConfiguratoinAction typealias and the LoadableImage.fromUrl
  completion gain @Sendable or @MainActor, which Swift 6 requires.
• CocoaPods support is removed. The podspec is deleted.
• swift-tools-version moves from 5.2 to 5.9, so building the package requires Xcode 15. Runtime
  deployment targets are unchanged.

Behavior changes

• Date.nz.start(of:) and end(of:) returned a date in the previous unit for .month, .year,
  .quarter and .era, because the implementation wrote zero into one based calendar fields. For
  example start(of: .month) on 2020-09-13 returned 2020-08-31. Both now use
  Calendar.dateInterval(of:for:) and return correct results. Code that compensated for the old
  behavior must drop the compensation. The week cases still snap to Sunday and ignore the
  calendar's firstWeekday, which is unchanged and covered by a test.
• String.nz.isVersion(...) returned inverted results whenever the two versions had a different
  number of components, so "2.0".nz.isVersion(greaterThan: "1.9.9") was false. Comparison is
  now component wise and numeric, which also fixes double digit components, so "1.10" is
  correctly greater than "1.9".
• Assigning nil to an optional KeychainProperty now removes the keychain entry. Previously it
  stored the string null, because JSONEncoder encodes a top level nil as a valid JSON
  fragment. A property with a non nil initial value therefore now reports that initial value
  after a nil assignment, where it previously read back as nil.
• Calendar.Component.nz.allComponents no longer lists .timeZone twice and now includes
  .weekdayOrdinal, plus .isLeapMonth on systems that have it.
• UIColor(hex:) no longer returns black for unparseable input. It returns nil.
• Bundle.nz.appVersion now reads the bundle it is called on rather than always reading
  Bundle.main, so a framework bundle reports its own version. Bundle.main.nz.appVersion is
  unchanged.
• DelayedAction.cancel() now returns false when nothing is pending. It previously returned
  true for every call after the first perform, including after the action had already run,
  because the finished work item was never cleared.

Fixed

• DispatchQueue.nz.once deadlocked when called from more than one thread. It synchronized on a
  Swift metatype, which does not bridge to a stable lock object, so the lock was acquired and never
  released. It now uses a lock held by a dedicated storage type, and a test drives it from many
  threads concurrently.
• AtomicAsyncOperation wedged permanently when its action called the finish closure
  synchronously, because the action ran while the semaphore was held and the finish path waited on
  that same semaphore. No completion ever fired. Synchronous and asynchronous actions both work now.
• JSONDecoder.DateDecodingStrategy.nz.customISO8601 was unreachable. The conformance was declared
  on DataDecodingStrategy while the member was declared on DateDecodingStrategy, so the symbol
  could not be called at all.
• UIControl.nz.addAction(for:_:) left a dangling target. The closure holder was associated with
  the temporary namespace struct rather than the control, under a key that was only valid for the
  duration of the call, so it was released immediately.
• UIColor(hex:) ignored the result of its scanner, did not support three digit shorthand, and
  shifted the colour channels for eight digit notation while discarding the embedded alpha.
• Keychain read, write and encode failures were swallowed silently, so a failed write left the
  caller with no signal.
• DefaultsProperty used setValue(_:forKey:), which is key value coding rather than the
  UserDefaults API.
• Tests covering navigation completions on the non animated path, where the completion runs
  without waiting for a transition coordinator. The animated path still has no test, because it
  needs a real window and a real transition.
• Navigation completions passed to pushViewController, popViewController,
  popToViewController and popToRootViewController could silently never run. They were attached
  with CATransaction.setCompletionBlock, but a navigation transition is driven by the controller's
  transition coordinator rather than by the surrounding transaction. They now run through the
  transition coordinator, and run immediately when there is no transition in flight.

Added

• Swift Testing suites for all four products: 278 tests on macOS and 173 on an iOS simulator. Line
  coverage is 98.05% for NerdzCore, 97.88% for NerdzDate and 100% for NerdzKeychain.
• KeychainPropertyError, KeychainPropertyErrorHandler and an onError: parameter on
  KeychainProperty.init, so failures are observable. The default handler does nothing, so
  existing call sites are unaffected.
• UIColor.hex(_:alpha:fallback:), plus support for three and four digit shorthand, eight digit
  notation with an embedded alpha, a leading #, and surrounding whitespace.
• DocC catalogs for NerdzCore and NerdzDate, published to GitHub Pages on release.
• GitHub Actions CI covering Linux, macOS and an iOS simulator, plus a tag driven release workflow.
• Platform declarations for iOS, macOS, tvOS, watchOS and visionOS, where the package previously
  declared iOS only.
• Rewritten README documenting the product layout, with every snippet compiled against the real API.

Removed

• The CocoaPods podspec.
• A committed docs/ directory of generated documentation, its Firebase hosting configuration and
  workflows, the Xcode project, Package.resolved and .swiftpm.

Notes

• NerdzKeychain cannot build on Linux, because KeychainAccess imports Security. NerdzCore and
  NerdzDate do build there, with the exception of DispatchQueue.nz.once(per:token:action:),
  which needs the Objective C runtime and is compiled out.
• Date values stored through KeychainProperty and DefaultsProperty are encoded as ISO8601 and
  lose sub second precision. This is unchanged, and it is not corrected here because a decoder
  configured for fractional seconds rejects timestamps that lack them, which would break reading
  values already stored by 1.x.