Gradle Build Cache Deep Dive

Walk through how Gradle's build cache actually works at the hash level — task input fingerprinting, path sensitivity, relocatability pitfalls with KMP expect/actual — then show a practical remote cache setup using a cheap object storage backend (S3-compatible or self-hosted) that makes CI and local builds share artifacts. Cover the non-obvious cache misses: annotation processor non-determinism, absolute paths leaking into inputs, BuildConfig timestamp poisoning, and Kotlin compiler flags that silently change between IDE and CLI. Include real before/after build scan data.