[dart-announce] Announcing Dart SDK 1.12

['Seth Ladd' via Dart Announcements]

Dart 1.12 is now available for download!

Please check out the CHANGELOG below. As always, we look forward to your feedback.

Thanks for using Dart!

1.12.0

Language changes

• Null-aware operators
  • ??: if null operator. expr1 ?? expr2 evaluates to expr1 if not null, otherwise expr2.
  • ??=: null-aware assignment. v ??= expr causes v to be assigned expr only if v is null.
  • x?.p: null-aware access. x?.p evaluates to x.p if x is not null, otherwise evaluates to null.
  • x?.m(): null-aware method invocation. x?.m() invokes m only if x is not null.

Core library changes

• dart:async

  • StreamController added setters for the onListen, onPause, onResume and onCancel callbacks.

• dart:convert

  • LineSplitter added a split static method returning an Iterable.

• dart:core

  • Uri class now perform path normalization when a URI is created. This removes most .. and . sequences from the URI path. Purely relative paths (no scheme or authority) are allowed to retain some leading "dot" segments. Also added hasAbsolutePath, hasEmptyPath, and hasScheme properties.

• dart:developer

  • New log function to transmit logging events to Observatory.

• dart:html

  • NodeTreeSanitizer added the const trusted field. It can be used instead of defining aNullTreeSanitizer class when calling setInnerHtml or other methods that create DOM from text. It is also more efficient, skipping the creation of a DocumentFragment.

• dart:io

  • Added two new file modes, WRITE_ONLY and WRITE_ONLY_APPEND for opening a file write only. eaeecf2
  • Change stdout/stderr to binary mode on Windows. 4205b29

• dart:isolate

  • Added onError, onExit and errorsAreFatal parameters to Isolate.spawnUri.

• dart:mirrors

  • InstanceMirror.delegate moved up to ObjectMirror.
  • Fix InstanceMirror.getField optimization when the selector is an operator.
  • Fix reflective NoSuchMethodErrors to match their non-reflective counterparts when due to argument mismatches. (VM only)

Tool changes

• Documentation tools

  • dartdoc is now the default tool to generate static HTML for API docs. Learn more.

  • docgen and dartdocgen have been deprecated. Currently plan is to remove them in 1.13.

• Formatter (dartfmt)

  • Over 50 bugs fixed.

  • Optimized line splitter is much faster and produces better output on complex code.

• Observatory

  • Allocation profiling.

  • New feature to display output from logging.

  • Heap snapshot analysis works for 64-bit VMs.

  • Improved ability to inspect typed data, regex and compiled code.

  • Ability to break on all or uncaught exceptions from Observatory's debugger.

  • Ability to set closure-specific breakpoints.

  • 'anext' - step past await/yield.

  • Preserve when a variable has been expanded/unexpanded in the debugger.

  • Keep focus on debugger input box whenever possible.

  • Echo stdout/stderr in the Observatory debugger. Standalone-only so far.

  • Minor fixes to service protocol documentation.

• Pub

  • Breaking: various commands that previously ran pub get implicitly no longer do so. Instead, they merely check to make sure the ".packages" file is newer than the pubspec and the lock file, and fail if it's not.

  • Added support for --verbosity=error and --verbosity=warning.

  • pub serve now collapses multiple GET requests into a single line of output. For full output, use --verbose.

  • pub deps has improved formatting for circular dependencies on the entrypoint package.

  • pub run and pub global run

    • Breaking: to match the behavior of the Dart VM, executables no longer run in checked mode by default. A--checked flag has been added to run them in checked mode manually.

    • Faster start time for executables that don't import transformed code.

    • Binstubs for globally-activated executables are now written in the system encoding, rather than always inUTF-8. To update existing executables, run pub cache repair.

  • pub get and pub upgrade

    • Pub will now generate a ".packages" file in addition to the "packages" directory when running pub get or similar operations, per the package spec proposal. Pub now has a --no-package-symlinks flag that will stop "packages" directories from being generated at all.

    • An issue where HTTP requests were sometimes made even though --offline was passed has been fixed.

    • A bug with --offline that caused an unhelpful error message has been fixed.

    • Pub will no longer time out when a package takes a long time to download.

  • pub publish

    • Pub will emit a non-zero exit code when it finds a violation while publishing.

    • .gitignore files will be respected even if the package isn't at the top level of the Git repository.

  • Barback integration

    • A crashing bug involving transformers that only apply to non-public code has been fixed.

    • A deadlock caused by declaring transformer followed by a lazy transformer (such as the built-in $dart2jstransformer) has been fixed.

    • A stack overflow caused by a transformer being run multiple times on the package that defines it has been fixed.

    • A transformer that tries to read a non-existent asset in another package will now be re-run if that asset is later created.

VM Service Protocol Changes

• BREAKING The service protocol now sends JSON-RPC 2.0-compatible server-to-client events. To reflect this, the service protocol version is now 2.0.

• The service protocol now includes a "jsonrpc" property in its responses, as opposed to "json-rpc".

• The service protocol now properly handles requests with non-string ids. Numeric ids are no longer converted to strings, and null ids now don't produce a response.

• Some RPCs that didn't include a "jsonrpc" property in their responses now include one.

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