KSP 2.3.8 does not always generate sources

[SimonMarquis]

This issue appears randomly, and we are not able to reproduce consistently!

On an ephemeral CI the compileTestKotlin task does not take the ksp generated source in its javaSources input.

By looking at the kspTestKotlin build cache entries: in the failing build, the cache entry does not contain the expected files.

• build A

cache-entry-a5b216b26ea784c150d527b4e7dd722c
├── METADATA
├── missing-tree-kspConfig.classOutputDir
├── missing-tree-kspConfig.kotlinOutputDir
├── missing-tree-kspConfig.resourceOutputDir
└── tree-kspConfig.javaOutputDir
    └── fr
        └── leboncoin
            └── repositories
                └── vehiclecashpurchase
                    ├── injection
                    │   └── DaggerTestComponent.java
                    └── VehicleCashPurchaseApiServiceTest_MembersInjector.java

• build B

cache-entry-5b4e74b295426adec6ee0aca799d57b3
├── METADATA
├── missing-tree-kspConfig.classOutputDir
├── missing-tree-kspConfig.javaOutputDir
├── missing-tree-kspConfig.kotlinOutputDir
└── missing-tree-kspConfig.resourceOutputDir

---

We then re-tried with a --rerun-tasks, and compileTestKotlin was successful (javaSources inputs are back).

---

Even stranger, both build cache results for the kspTestKotlin tasks have the same key, but different contents:

• Failing build:

Build cache result	Miss (local), Hit (remote), Store (local)
Cache key	5b4e74b295426adec6ee0aca799d57b3
Cache artifact	602 B / 5 entries

• Successful build:

Build cache result	Store (local and remote)
Cache key	5b4e74b295426adec6ee0aca799d57b3
Cache artifact	1.8 KiB / 12 entries

[jaschdoc]

Thank you for the bug report @SimonMarquis!

@hfmehmed, do you know if this is related to the Gradle plugin or possibly #2953 or #2947?

[hfmehmed]

I would be surprised if it related to any of those but yes it looks like it could be gradle related issue. Need to investigate more. It's a shame that there is not a consistent reproduction - could be a race condition somewhere