This document lists common problems encountered by CTL users and developers.
Table of Contents
This is probably because npm is used directly. This is something users have reported when using npm install instead of having Nix manage the node dependencies (done automatically with nix develop, but if you have node_modules present in the working directory it will shadow the ones from the Nix store).
You can prevent npm from ever installing to local node_modules by enabling the packageLockOnly flag in the shell argument to purescriptProject. When enabled, npm i will always act as if the --package-lock-only flag has been passed. This is not enabled by default, but we recommend enabling it.
Local cardano-node lags behind the global network time, so when using time conversion functions (slotToPosixTime, posixTimeToSlot, etc.) users should be aware that the node sees time differently from the OS. During normal runs, the lag can be somewhere between 0 and 200 seconds.
To do anything time-related, it's best to rely on local node chain tip time, instead of using Date.now() as a source of truth. This is often a requirement when using mustValidateIn, because the node will reject the transaction if it appears too early.
Time/slot conversion functions depend on eraSummaries Ogmios local state query, that returns era bounds and slotting parameters details, required for proper slot arithmetic. The most common source of the problem is that Ogmios does not return enough epochs into the future.
Q: I'm getting Uncomputable slot arithmetic; transaction's validity bounds go beyond the foreseeable end of the current era: PastHorizon
Ensure your transaction's validity range does not go over SafeZone slots of the current era. The reason for this kind of errors is that time-related estimations are slot-based, and future forks may change slot lengths. So there is only a relatively small time window in the future during which it is known that forks cannot occur.
Haskell's aeson library encodes long integers as JSON numbers, which leads to numeric truncation on decoder side if JS Number is used. Unfortunately, purescript-argonaut does not allow to use another type, because the truncation happens during JSON.parse call. purescript-aeson is our custom solution that bypasses this limitation by storing numbers as strings. It exposes a very similar API.
This is because the node hasn't fully synced. The protocol parameter name changed from coinsPerUtxoWord to coinsPerUtxoByte in Babbage. CTL only supports the latest era, but Ogmios returns different protocol parameters format depending on current era of a local node.
The most likely reason for this is that spawning the external processes from Contract.Test.Plutip fails. Make sure that all of the required services are on your $PATH (see more here; you can also set shell.withRuntime = true; to ensure that these are always added to your shell environment when running nix develop). Also, check your logs closely. You might see something like:
/home/me/ctl-project/output/Effect.Aff/foreign.js:532
throw util.fromLeft(step);
^
Error: Command failed: initdb /tmp/nix-shell.2AQ4vD/nix-shell.6SMFfq/6s0mchkxl6w9m3m7/postgres/data
initdb: error: invalid locale settings; check LANG and LC_* environment variables
The last line is the the most important part. Postgres will fail if your locale is not configured correctly. We could try to do this in the shellHook when creating the project devShell, but dealing with locales is non-trivial and could cause more issues than it solves. You can find more information online regarding this error and how to potentially solve it, for example here and here.
If the different derivation builders that purescriptProject gives you out-of-the-box (e.g. runPursTest, bundlePursProject, etc...) are not sufficient, you can access the compiled project (all of the original src argument plus the output directory that purs produces) and the generated node_modules using the compiled and nodeModules attributes, respectively. These can be used to write your own derivations without needing to recompile the entire project (that is, the generated output can be shared between all of your Nix components). For example:
{
project = pkgs.purescriptProject { /* snip */ };
# `purescriptProject` returns a number of specialized builders
bundle = project.bundlePursProject { /* snip */ };
# And attributes allowing you to create your own without
# needing to deal with `spago2nix` or recompiling your
# project in different components
specialPackage = pkgs.runCommand "my-special-package"
{
NODE_PATH = "${project.nodeModules}/lib/node_modules";
}
''
cp -r ${project.compiled}/* .
# Do more stuff ...
'';
}