# Weird error: I don't understand why execution is interrupted **URL:** \ **Category:** Motoko\ **Created:** [October 6, 2024, 6:05pm UTC](https://forum.dfinity.org/t/weird-error-i-dont-understand-why-execution-is-interrupted/35883 "2024-10-06T18:05:24Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![qwertytrewq](https://sea1.discourse-cdn.com/flex023/user_avatar/forum.dfinity.org/qwertytrewq/32/10423_2.png) [@qwertytrewq](https://forum.dfinity.org/u/qwertytrewq)\ **Post date:** [October 6, 2024, 6:05pm UTC](https://forum.dfinity.org/t/weird-error-i-dont-understand-why-execution-is-interrupted/35883/1 "2024-10-06T18:05:24Z")
I have: ```auto Debug.print("A6"); let inst = await pm.installPackageWithPreinstalledModules({ packageName = "icpack"; version = "0.0.1"; // TODO: should be `"stable"` preinstalledModules = [("frontend", frontend)]; repo; caller; callback = ?bootstrapBackendCallback; }); Debug.print("A7"); ``` and ```auto public shared({caller}) func installPackageWithPreinstalledModules({ packageName: Common.PackageName; version: Common.Version; preinstalledModules: [(Text, Principal)]; repo: Common.RepositoryPartitionRO; caller: Principal; callback: ?(shared ({ installationId: Common.InstallationId; can: Principal; caller: Principal; }) -> async ()); }) : async {installationId: Common.InstallationId} { Debug.print("B1"); onlyOwner(caller); Debug.print("B2"); await* _installPackage({caller; packageName; version; preinstalledModules = ?preinstalledModules; repo; callback}); }; ``` How so that `A6` is printed and `B1` isn’t?! `...` `2024-10-06 17:54:12.074027733 UTC: [Canister by6od-j4aaa-aaaaa-qaadq-cai] A6` `2024-10-06 17:54:13.406173747 UTC: [Canister 6zqe7-uuaaa-aaaaa-qacia-cai] Indirect caller: IC0503: Error from Canister 66rcl-zmaaa-aaaaa-qaciq-cai: Canister called `ic0.trap` with message: IDL error: unexpected IDL type when parsing Principal.` `Consider gracefully handling failures from this canister or altering the canister to handle exceptions. See documentation: http://internetcomputer.org/docs/current/references/execution-errors#trapped-explicitly` There isn’t anything between `A6` and `B1` that would prevent `B1` to be printed. That a one-way method fails with an error (`Indirect caller` error is printed by `Debug.print` in an one-way tunction) during execution of the ongoing code should not prevent `B1` to be printed… I misunderstand something. ---
**Author:** ![skilesare](https://sea1.discourse-cdn.com/flex023/user_avatar/forum.dfinity.org/skilesare/32/5609_2.png) [@skilesare](https://forum.dfinity.org/u/skilesare)\ **Post date:** [October 6, 2024, 7:57pm UTC](https://forum.dfinity.org/t/weird-error-i-dont-understand-why-execution-is-interrupted/35883/2 "2024-10-06T19:57:00Z")
Your candid types are off so the function is never being called…not at. Place to inspect, but check that your types exactly line up. Something is wrong with a principal. It expects one but finds something else. opt principal maybe? ---
**Author:** ![qwertytrewq](https://sea1.discourse-cdn.com/flex023/user_avatar/forum.dfinity.org/qwertytrewq/32/10423_2.png) [@qwertytrewq](https://forum.dfinity.org/u/qwertytrewq)\ **Post date:** [October 6, 2024, 8:08pm UTC](https://forum.dfinity.org/t/weird-error-i-dont-understand-why-execution-is-interrupted/35883/3 "2024-10-06T20:08:52Z")
I told that I also have a trouble with a one-way function. (I do understand that I pass a wrong type to it.) But why `A6` is printed and `B1` isn’t. Why? It is in another fiber of execution and should not be affected by the calling (or not) the one-way function. What is wrong HERE? ---
**Author:** ![qwertytrewq](https://sea1.discourse-cdn.com/flex023/user_avatar/forum.dfinity.org/qwertytrewq/32/10423_2.png) [@qwertytrewq](https://forum.dfinity.org/u/qwertytrewq)\ **Post date:** [October 6, 2024, 8:38pm UTC](https://forum.dfinity.org/t/weird-error-i-dont-understand-why-execution-is-interrupted/35883/4 "2024-10-06T20:38:59Z")
@skilesare The following runs just fine (despite the one-way function fails), printing all the 1000 numbers: ```auto import Debug "mo:base/Debug"; actor { public shared func greet() : async () { oneWay(); var i = 0; while (i < 1000) { Debug.print(debug_show(i)); i += 1; }; }; public shared func oneWay(): () { let _ = 1 / 0; } }; ``` But my function in a way that I can’t understand fails to print `B1`. Why?! Is refusal to print `B1` somehow related with calling a one-way function above in my code (not shown)? ---
**Author:** ![skilesare](https://sea1.discourse-cdn.com/flex023/user_avatar/forum.dfinity.org/skilesare/32/5609_2.png) [@skilesare](https://forum.dfinity.org/u/skilesare)\ **Post date:** [October 6, 2024, 9:52pm UTC](https://forum.dfinity.org/t/weird-error-i-dont-understand-why-execution-is-interrupted/35883/5 "2024-10-06T21:52:15Z")
InstallPackageWithPreinstall is never getting executed because the canister can’t interpret your parameters The trap is from Message parsing code not from inside your function. ‘’’ `Canister called ` ic0.trap`with message: IDL error: unexpected IDL type when parsing Principal.` ‘’’ ---
**Author:** ![skilesare](https://sea1.discourse-cdn.com/flex023/user_avatar/forum.dfinity.org/skilesare/32/5609_2.png) [@skilesare](https://forum.dfinity.org/u/skilesare)\ **Post date:** [October 6, 2024, 9:55pm UTC](https://forum.dfinity.org/t/weird-error-i-dont-understand-why-execution-is-interrupted/35883/6 "2024-10-06T21:55:03Z")
See [Motoko: Interesting one shot behavior - #2 by claudio](https://forum.dfinity.org/t/motoko-interesting-one-shot-behavior/16086/2) for some one shot explanations. ---
**Author:** ![qwertytrewq](https://sea1.discourse-cdn.com/flex023/user_avatar/forum.dfinity.org/qwertytrewq/32/10423_2.png) [@qwertytrewq](https://forum.dfinity.org/u/qwertytrewq)\ **Post date:** [October 7, 2024, 3:01am UTC](https://forum.dfinity.org/t/weird-error-i-dont-understand-why-execution-is-interrupted/35883/7 "2024-10-07T03:01:30Z")
How so, “canister can’t interpret your parameters”? I call a Motoko function directly, not through some fancy e.g. management canister method. It looks like that the parameters cannot be mis-interpreted (but they are, how so?) And yes, “Message parsing code not from inside your function” because it starts with `Indirect caller:`, this way I log exceptions in a one-way function (so, yes, not from inside my function). What I don’t understand: If message passing to my function is correct, then why isn’t `B1` printed?!! The message passing bug is in another one-way function (not from inside my functions). Then how come that control does not reach `Debug.print("B1")`?! ---
**Author:** ![qwertytrewq](https://sea1.discourse-cdn.com/flex023/user_avatar/forum.dfinity.org/qwertytrewq/32/10423_2.png) [@qwertytrewq](https://forum.dfinity.org/u/qwertytrewq)\ **Post date:** [October 7, 2024, 11:16am UTC](https://forum.dfinity.org/t/weird-error-i-dont-understand-why-execution-is-interrupted/35883/8 "2024-10-07T11:16:22Z")
I’ve realized what happened: The `IC.install_code` is run before my code in an one-way function. And it is either not installed altogether or installed to late (after `await pm.installPackageWithPreinstalledModules(...)`. So, I am calling a canister with no code in it. ---
**Author:** ![skilesare](https://sea1.discourse-cdn.com/flex023/user_avatar/forum.dfinity.org/skilesare/32/5609_2.png) [@skilesare](https://forum.dfinity.org/u/skilesare)\ **Post date:** [October 7, 2024, 12:38pm UTC](https://forum.dfinity.org/t/weird-error-i-dont-understand-why-execution-is-interrupted/35883/9 "2024-10-07T12:38:26Z")
> [@qwertytrewq](#): > > nexpected IDL type when parsing Principal That makes sense. The error comes from [terraform-provider-ic/internal/provider/arg.go at aec0f7d61e5e3e0c2920db6f5394ef1a23a3d0cb · dfinity/terraform-provider-ic · GitHub](https://github.com/dfinity/terraform-provider-ic/blob/aec0f7d61e5e3e0c2920db6f5394ef1a23a3d0cb/internal/provider/arg.go#L76) which is in the terraform provider.