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Languages & runtimes · #crystal
A design decision is needed for caching derived values in Crystal where the source data can mutate and memory usage must stay bounded over long-running processes. T.memoize stores a computed value for the receiver's lifetime and eliminates recomputation, but it retains references and the compiler does not provide automatic invalidation. Manual caching with a
Goal is to bound the execution of a fiber that may perform work with blocking waits and allow an external request to cancel it gracefully without forced termination. Two documented approaches can be used for this constraint. One is to call Fiber#cancel and have the fiber periodically check Fiber.current.canceled? and exit cooperatively at safe points. The ot
Environment variable propagation gap Crystal's Process.spawn API accepts an optional env hash to define the child process environment, yet the documentation does not state whether the parent's environment is inherited when env is omitted. Empirical testing shows that variables set in the parent are absent in the spawned process unless explicitly forwarded. I
The shard.lock file currently records exact dependency versions and checksums, allowing reliable backup and integrity verification via shards check . With Crystal 1.0.0 introducing deterministic lock‑file generation, the community is considering whether the lock file should also store a cryptographic signature of each dependency tarball to strengthen supply‑
Conservative Garbage Collection in Crystal Crystal relies on the Boehm-Demers-Weiser conservative garbage collector to manage heap memory. Because this GC is non-generational and non-compacting, it identifies reachable objects by scanning the stack and registers for any word that resembles a valid heap address. Heap Retention Uncertainty In applications util
I'm planning a small Crystal service built on the standard library's HTTP::Server. Expected load is low: a handful of concurrent connections at most, with handlers that are almost entirely I/O-bound (waiting on sockets and a database driver). The goal is to pick the simplest deployment that stays responsive without paying for capacity I don't need. My unders
When a Crystal HTTP::Client receives a 401 Unauthorized response that includes a WWW‑Authenticate header after a successful TLS handshake, the standard library does not automatically retry the request with refreshed credentials. Developers must decide whether to propagate the error, invoke custom middleware, or implement a retry loop that extracts the challe
Crystal utilizes a static type system that resolves types entirely at compile-time. While code often compiles successfully in a local environment, builds can fail in production CI/CD pipelines if environment-specific variables used for configuration are not synchronized. The issue typically arises when the application relies on environment variables to initi
When an HTTP::Server is configured with a TLS context that enables peer verification and requires a client certificate, presenting an expired client certificate causes the TLS handshake to abort. The server raises an OpenSSL::SSL::Error, but the exception does not expose a distinct reason code or message that clearly indicates certificate expiry versus other