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https://issues.apache.org/jira/browse/GROOVY-9742?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Daniel Sun resolved GROOVY-9742.
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Fix Version/s: 5.0.0-alpha-13
Resolution: Fixed
> GroovyClassLoader.parseClass() StampedCommonCache.getAndPut() hang
> ------------------------------------------------------------------
>
> Key: GROOVY-9742
> URL: https://issues.apache.org/jira/browse/GROOVY-9742
> Project: Groovy
> Issue Type: Bug
> Components: groovy-runtime
> Affects Versions: 3.0.5
> Environment: Java version AdoptOpenJDK (build 25.262-b10, mixed mode)
> Gradle version 6.6.1
> Groovy version 3.0.5
> Reporter: Chiang Seng Chang
> Assignee: Daniel Sun
> Priority: Major
> Fix For: 5.0.0-alpha-13
>
> Attachments: g3cl.tar.gz
>
>
> We have an IDE-like app which allows our coders to develop groovy scripts and
> classes.
> Essentially, the coders would write groovy sources and test them in the app.
> We made a CustomClassLoader which is created and destroyed for each test run,
> so that the app need no be restarted every time there is code change.
> In Groovy 3.0.5, the GroovyClassLoader's cache is refactored to use
> StampedCommonCache, which does not support recursion.
> This is the distilled simplified version of our CustomClassLoader:
> {noformat}
> public class CustomGroovyClassLoader extends ClassLoader {
> public CustomGroovyClassLoader(ClassLoader parent) {
> super(parent);
> groovyClassLoader = new GroovyClassLoader(this);
> }
> private final File srcDir = new File("./src/main/groovy");
> private final GroovyClassLoader groovyClassLoader;
> @Override
> protected Class<?> loadClass(String name, boolean resolve)
> throws ClassNotFoundException {
> synchronized (getClassLoadingLock(name)) {
> Class<?> c = doFindClass(name);
> if (c != null) {
> if (resolve) {
> resolveClass(c);
> }
> return c;
> }
> }
> return super.loadClass(name, resolve);
> }
> private Class<?> doFindClass(String name) {
> File classFile = new File(srcDir, name.replace('.', '/') + ".groovy");
> if (classFile.exists()) {
> try {
> System.out.println("PARSE\t: " + name);
> Class<?> clz = groovyClassLoader.parseClass(classFile);
> System.out.println("PARSED\t: " + clz);
> return clz;
> }
> catch (IOException e) {
> throw new RuntimeException(e);
> }
> }
> return null;
> }
> }
> {noformat}
> Essentially, it uses the GroovyClassLoader.parseClass() for our test classes.
> Here are the 2 classes to demonstrate the issue:
> {noformat}
> package foo
> import groovy.transform.CompileStatic
> @CompileStatic
> interface Bar {}
> {noformat}
> {noformat}
> package foo
> import groovy.transform.CompileStatic
> @CompileStatic
> class Foo implements Bar {}
> {noformat}
> And the test harness:
> {noformat}
> package foo;
> public class TestHarness {
> public static void main(String[] args) throws Exception {
> ClassLoader pcl = TestHarness.class.getClassLoader();
> CustomGroovyClassLoader ccl = new CustomGroovyClassLoader(pcl);
> Class<?> clz = ccl.loadClass("foo.Foo");
> System.out.println("DONE\t: " + clz);
> }
> }
> {noformat}
> The harness attempt to load Foo.groovy.
> The sequence of events would be:
> # CustomClassLoader.loadClass(Foo)
> # GroovyClassLoader.parseClass(Foo.groovy)
> # sourceCache.getAndPut(Foo)
> # Since Foo implements Bar, CustomClassLoader is called to load Bar
> # which in turn calls GroovyClassLoader.parseClass(Bar.groovy)
> # and sourceCache.getAndPut(Bar)
> # Since StampedCommonCache does not support recursion, the loading hangs.
> The attached project can be run using ./gradlew run to demonstrate the
> hanging.
> It seems to me that the GroovyClassLoader needs to support recursion for this
> use case.
> Or perhaps the CustomClassLoader is implemented wrongly?
> Groovy 2.5.12 does not have this issue because its GroovyClassLoader uses
> ConcurrentCommonCache.
>
>
>
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