build_runner

New Features

• Add an enableLowResourcesMode option to build and watch, which will consume less memory at the cost of slower builds. This is intended for use in resource constrained environments such as Travis.
• Add createBuildActions. After finding a list of Builders to run, and defining which packages need them applied, use this tool to apply them in the correct order across the package graph.

Deprecations

• Deprecate PackageGraph.orderedPackages and PackageGraph.dependentsOf.

Internal Improvements

• Outputs will no longer be rebuilt unless their inputs actually changed, previously if any transitive dependency changed they would be invalidated.
• Switched to using semantic analyzer summaries, this combined with the better input validation means that, ddc/summary builds are much faster on non-api affecting edits (dependent modules will no longer be rebuilt).
• Build script invalidation is now much faster, which speeds up all builds.

Bug Fixes

• The build actions are now checked against the previous builds actions, and if they do not match then a full build is performed. Previously the behavior in this case was undefined.
• Fixed an issue where once an edge between an output and an input was created it was never removed, causing extra builds to happen that weren't necessary.
• Build actions are now checked for overlapping outputs in non-checked mode, previously this was only an assert.
• Fixed an issue where nodes could get in an inconsistent state for short periods of time, leading to various errors.
• Fixed an issue on windows where incremental builds didn't work.

New features

• Added orderedPackages and dependentsOf utilities to PackageGraph.
• Added the noPubspec constructor to PackageNode.
• Added the PackageBuilder and PackageBuildAction classes. These builders only run once per package, and have no primary input. Outputs must be well known ahead of time and are declared with the Iterable<String> get outputs field, which returns relative paths under the current package.
• Added the isOptional field to BuildAction. Setting this to true means that the action will not run unless some other non-optional action tries to read one of the outputs of the action.
• Breaking: PackageNode.location has become PackageNode.path, and is now a String (absolute path) instead of a Uri; this prevents needing conversions to/from Uri across the package.
• Breaking: RunnerAssetReader interface requires you to implement MultiPackageAssetReader and DigestAssetReader. This means the packageName named argument has changed to package, and you have to add the Future<Digest> digest(AssetId id) method. While technically breaking most users do not rely on this interface explicitly.
  • You also no longer have to implement the Future<DateTime> lastModified(AssetId id) method, as it has been replaced with the DigestAssetReader interface.
• Breaking: ServeHandler.handle has been replaced with Handler ServeHandler.handleFor(String rootDir). This allows you to create separate handlers per directory you want to serve, which maintains pub serve conventions and allows interoperation with pub run test --pub-serve=$PORT.

Bug fixes

• Breaking: All AssetReader#findAssets implementations now return a Stream<AssetId> to match the latest build package. This should not affect most users unless you are extending the built in AssetReaders or using them in a custom way.
• Fixed an issue where findAssets could return declared outputs from previous phases that did not actually output the asset.
• Fixed two issues with writeToCache:
  • Over-declared outputs will no longer attempt to build on each startup.
  • Unrecognized files in the cache dir will no longer be treated as inputs.
• Asset invalidation has changed from using last modified timestamps to content hashes. This is generally much more reliable, and unblocks other desired features.

Internal changes

• Added PackageGraphWatcher and PackageNodeWatcher as a wrapper API, including an AssetChange class that is now consistently used across the package.

Internal Improvements

• Now using package:pool to limit the number of open file handles.

Bug fixes

• Fixed an issue where the asset graph could get in an invalid state if you aren't setting writeToCache: true.

• Breaking: Removed buildType field from BuildResult.
• Breaking: watch now returns a ServeHandler instead of a Stream<BuildResult>. Use ServeHandler.buildResults to get back to the original stream.
• Breaking: serve has been removed. Instead use watch and use the resulting ServeHandler.handle method along with a server created in the client script to start a server.
• Prevent reads into .dart_tool for more hermetic builds.
• Bug Fix: Rebuild entire asset graph if the build script changes.
• Add writeToCache argument to build and watch which separates generated files from the source directory and allows running builders against other packages.
• Allow the latest version of package:shelf.

• Depend on build 0.10.x and build_barback 0.4.x

• Bug fix: Don't crash after a Builder reads a file from another package.

• Bug fix: Don't try to delete files generated for other packages.

• Breaking: The PhaseGroup class has been replaced with a List<BuildAction> in build, watch, and serve. The PhaseGroup and Phase classes are removed. If your current build has multiple actions in a single phase which are depending on not seeing the outputs from other actions in the phase you will need to instead set up the InputSets so that the outputs are filtered out.
• Breaking: The resolvers argument has been removed from build, watch, and serve.
• Allow package:build v0.10.x

• Support the latest release of analyzer.

• Support the latest release of build_barback.

• Support for build 0.9.0

• Internal refactoring of RunnerAssetReader.
• Support for build 0.8.0
• Add findAssets on AssetReader implementations
• Limit Asset reads to those which were available at the start of the phase. This might cause some reads which uses to succeed to fail.

• Bug Fix: Update AssetGraph version so builds can be run without manually deleting old build directory.
• Bug Fix: Check for unreadable assets in an async method rather than throw synchronously

Bug Fixes

• Fixed a race condition bug 175 that could cause invalid output errors.

Breaking Changes

• RunnerAssetWriter now requires an additional field, onDelete which is a callback that must be called synchronously within delete.

Add support for the new bytes apis in build.

New Features

• FileBasedAssetReader and FileBasedAssetWriter now support reading/writing as bytes.

Breaking Changes

• Removed the AssetCache, CachedAssetReader, and CachedAssetWriter. These may come back at a later time if deemed necessary, but for now they just complicate things unnecessarily without proven benefits.
• BuildResult#outputs now has a type of List<AssetId> instead of List<Asset>, since the Asset class no longer exists. Additionally this was wasting memory by keeping all output contents around when it's not generally a very useful thing outside of tests (which retain this information in other ways).