To snapshot a Java class (+ its fields and methods), previously we used
Gson to serialize a class field/method to a string via reflection, and
hash that string.
We now use an ASM ClassWriter to write a placeholder class containing
the field/method of interest and hash the bytecode of that class.
One experiment showed that this new approach is ~10 times faster than
the previous approach (140s down to 16s when snapshotting 600 jars).
Test: Updated expectation files for JavaClassSnapshotterTest unit tests
+ Existing integration tests to prevent regression
^KT-52141 In Progress
1. CLASS_LEVEL: allows tracking whether a .class file has changed
without tracking what specific parts of the .class file (e.g.,
fields or methods) have changed.
2. CLASS_MEMBER_LEVEL: allows tracking not only whether a .class file
has changed but also what specific parts of the .class file (e.g.,
fields or methods) have changed.
The idea is that for better performance we will use CLASS_LEVEL for
classpath entries that are usually unchanged, and CLASS_MEMBER_LEVEL
for classpath entries that are frequently changed. We'll work out the
specifics in a following commit after some measurements.
Support running kotlinc on Windows in ClasspathSnapshotTestCommon
Also add tests for different Kotlin class kinds.
Add unit tests for CLASS_LEVEL snapshotting and diffing
Test: Updated ClasspathSnapshotterTest + ClasspathChangesComputerTest
Add ClasspathChangesComputerTest.testMixedClassSnapshotGranularities
to make it easier to add more tests in the next commits.
- Add unit tests for constants and inline functions
Also add tests for different kinds of Kotlin classes: CLASS,
FILE_FACADE, MULTIFILE_CLASS.
-Add unit test for nested classes
Also remove the existing integration test for nested classes to keep the
integration tests focused on the key scenarios while unit tests will
cover the corner cases.
Ignore inline functions that are private
Currently, we shrink classpath snapshots at 2 steps:
- Classpath diffing: Shrink the current classpath snapshot against
the previous lookup symbols
- Classpath snapshot saving: Shrink the current classpath snapshot
against the current lookup symbols
With this commit, the shrinking at the second step is now incremental.
The shrinking at the first step is still non-incremental.
Also visit a class file with ASM once to extract all information we need
in advance, instead of visiting the class file each time some piece of
info is needed.
Hung Nguyen