From mobile apps to microservices, from small startups to big enterprises, Gradle helps teams build, automate and deliver better software, faster.

Gradle Community

ah nice. though I wish gradle would take care of that :slightly_smiling_face:

I switched it to use

```    public interface SerializableFunction&lt;T,R&gt; extends Function&lt;T,R&gt;, Serializable {}```
instead of `Function` but I still see the same error

That is strange, I saw it working just this week…

E.g. such a task seems to work: <https://github.com/gradle/gradle/pull/21099/files#diff-47dd7a977888628e25e910d61889e23ac90911657aa4c0fcac58efcca8517e85R288-R329>

here's the changed task: <https://github.com/breskeby/elasticsearch/blob/improve-cc-test-coverage/build-tools-internal/src/main/java/org/elasticsearch/gradle/internal/test/rest/CopyRestTestsTask.java#L59|https://github.com/breskeby/elasticsearch/blob/improve-cc-test-coverage/build-tool[…]/elasticsearch/gradle/internal/test/rest/CopyRestTestsTask.java>

that is the test: <https://github.com/breskeby/elasticsearch/blob/improve-cc-test-coverage/build-tools-internal/src/integTest/groovy/org/elasticsearch/gradle/internal/test/rest/RestResourcesPluginFuncTest.groovy#L123-L180|https://github.com/breskeby/elasticsearch/blob/improve-cc-test-coverage/build-tool[…]ch/gradle/internal/test/rest/RestResourcesPluginFuncTest.groovy>


it fails with the error above, once I change the flag here to true <https://github.com/breskeby/elasticsearch/blob/96a2f88137ce6d61db2836c8bd9cfb866d8283ad/build-tools-internal/src/integTest/groovy/org/elasticsearch/gradle/internal/test/rest/RestResourcesPluginFuncTest.groovy#L126|https://github.com/breskeby/elasticsearch/blob/96a2f88137ce6d61db2836c8bd9cfb866d8[…]ch/gradle/internal/test/rest/RestResourcesPluginFuncTest.groovy>

Sorry I don't see in the test where you set the lambda (additionalConfigToFiletree)

I was thinking maybe the issue is that the lambda is using something from project or another object that is not serializable

Not the test sets it, but the task.
First of the last three links:
&gt; private SerializableFunction&lt;FileCollection, FileTree&gt; additionalConfigToFileTree = FileCollection::getAsFileTree;


Yes, I was looking for the usage in the test to see if the issue was that the lambda had a reference to project

the specific thing about that test in that test class compared to the other tests in that test class is that it invokes gradle twice so it actually tries to read the configuration-cache which failed

<@UAJKMRD2Q> In your case, you also need to fix `CopyRestApiTask` and not only `CopyRestTestsTask`, and then it works: <https://ge.gradle.org/s/p3caqd5ey6y4u/tests/overview>