Alexander Udalov
1d5d6b5b72
Preface: Kotlin 1.3 will be able to read metadata of .class files produced by Kotlin 1.4 (see KT-25972). Also, to simplify implementation and to improve diagnostic messages, we're going to advance JVM metadata version to 1.4.0 in Kotlin 1.4, and would like to keep it in sync with the compiler version thereafter. This presents a problem: in an unlikely event that before releasing 1.4, we find out that the metadata-reading implementation in 1.3 was incorrect, we'd like to be able to fix the bug in that implementation and _forbid_ 1.3 from reading metadata of 1.4. But prior to this commit the only way to do this was to advance the metadata version, in this case to 1.5, and that breaks the metadata/compiler version equivalence we'd like to keep. The solution is to add another boolean flag to the class file, called "strict metadata version semantics", which signifies that if this class file has metadata version 1.X, then it can only be read by the compilers of versions 1.X and greater. This flag effectively disables the smooth migration scenario proposed in KT-25972 (as does increasing metadata version by 2), and will be used only in hopeless situations as in the case described above.
Kotlin Libraries
This part of the project contains the sources of the following libraries:
- kotlin-stdlib, the standard library for Kotlin/JVM, Kotlin/JS and its additional parts for JDK 7 and JDK 8
- kotlin-reflect, the library for full reflection support
- kotlin-test, the library for multiplatform unit testing
- kotlin-annotations-jvm, the annotations to improve types in the Java code to look better when being consumed in the Kotlin code.
These libraries are built as a part of the root Gradle project.
Kotlin Maven Tools
This area of the project is the root for Maven build.
You can work with the maven modules of this maven project in IDEA from the root IDEA project. After importing you'll be able to explore maven projects and run goals directly from IDEA with the instruments on the right sidebar.
Building
You need to install a recent (at least 3.3) Maven distribution.
Before building this Maven project you need to build and install the required artifacts built with Gradle to the local maven repository, by issuing the following command in the root project:
./gradlew install
Note: on Windows type
gradlewwithout the leading./
This command assembles and puts the artifacts to the local maven repository to be used by the subsequent maven build. See also root ReadMe.md, section "Building".
Then you can build maven artifacts with Maven:
mvn install
If your maven build is failing with Out-Of-Memory errors, set JVM options for maven in MAVEN_OPTS environment variable like this:
MAVEN_OPTS="-Xmx2G"