| [](https://buildkite.com/bazel/kotlin-postsubmit) |
| |
| # Compilation Avoidance |
| |
| # ABI support |
| |
| **rules_kotlin** now supports compilation avoidance through the use of ABI jars (also known as |
| interface or header jars) for classpath dependencies. This can have significant performance wins for |
| non-ABI affecting changes since down stream recompilation can be avoided in such cases. |
| |
| This feature can be enabled through the `experimental_use_abi_jars` flag in the tool chain as |
| follows |
| |
| ```python |
| load("//kotlin:core.bzl", "define_kt_toolchain") |
| |
| |
| define_kt_toolchain( |
| name = "kotlin_toolchain", |
| experimental_use_abi_jars = True, |
| ) |
| ``` |
| |
| This feature is implemented using the Jetbrains Kotlin JvmABI compiler plugin for generating headers |
| for Kotlin code. Unfortunately there are some known bugs with this plugin that affect less than 1% |
| of targets. |
| * https://youtrack.jetbrains.com/issue/KT-40340 |
| * https://youtrack.jetbrains.com/issue/KT-40133 |
| |
| If you encounter such bugs, ABI generation can be disabled on a per target basis by setting the |
| following tag |
| |
| ```python |
| load("//kotlin:jvm.bzl", "kt_jvm_library") |
| |
| kt_jvm_library( |
| name = "framework", |
| tags = ["kt_abi_plugin_incompatible"], |
| ) |
| ``` |
| |
| Depending on your compiler version you may find non-public symbols in your ABI jar such as [internal declarations](https://youtrack.jetbrains.com/issue/KT-65690) or [effectively private classes](https://youtrack.jetbrains.com/issue/KT-64590). |
| Exclusion of these symbols from the ABI jar can be enabled through the `experimental_treat_internal_as_private_in_abi_jars` and `experimental_remove_private_classes_in_abi_jars` flags in addition to `experimental_use_abi_jars` flag when defining the toolchain as follows |
| |
| ```python |
| load("//kotlin:core.bzl", "define_kt_toolchain") |
| |
| |
| define_kt_toolchain( |
| name = "kotlin_toolchain", |
| experimental_use_abi_jars = True, |
| experimental_treat_internal_as_private_in_abi_jars = True, |
| experimental_remove_private_classes_in_abi_jars = True, |
| ) |
| ``` |
| |
| If you encounter bugs in older compiler versions such as [KT-71525](https://youtrack.jetbrains.com/issue/KT-71525) then ABI generation with only public symbols can be disabled on a per target basis by setting the following tags |
| |
| ```python |
| load("//kotlin:jvm.bzl", "kt_jvm_library") |
| |
| kt_jvm_library( |
| name = "framework", |
| tags = ["kt_treat_internal_as_private_in_abi_plugin_incompatible", "kt_remove_private_classes_in_abi_plugin_incompatible"], |
| ) |
| ``` |
