"this function call implicitly requires `system` capability and may perform undesired actions"

[vporton]

.mops/candb@1.0.7/src/CanisterActions.mo:60.9-60.28: warning [M0195], this function call implicitly requires systemcapability and may perform undesired actions (please review the call and provide a type instantiation to suppress this warning)

when compiling with

$ moc --version
Motoko compiler 0.11.0+ (source yh3wb1vx-vj8j4j32-k8gq4m8y-4cxlqinf)

[ByronBecker]

This is from the transferCyclesStopAndDeleteCanisters API in CanDBAdmin.mo

CanDB/src/CanDBAdmin.mo

Line 33 in d767609

public func transferCyclesStopAndDeleteCanisters(canisterIds: [Text]): async CanisterCleanupStatusMap {

It's used when you want to delete an array of canister ids in parallel. Essentially what it does is:

  /// 1. Calls the TransferCycles method of each canister actor (transferring cycles from your service partition canisters back to your CanDB Index canister actor)
  /// 2. Stops each canister
  /// 3. Deletes each canister

Step 1 is what's resulting in a system error, since the library is sending cycles.

You can also implement your own canister cycles cleanup if you want to avoid the warning, but I implemented it in the library so that you don't have to deal with it in the first place.