ibc-transfer transfer CLI panics when called with fewer than required positional arguments

[andressa-zignaly]

The ibc-transfer transfer CLI command panics with a runtime error when invoked with fewer than the required positional arguments, instead of failing gracefully with a validation error. This affects any Cosmos SDK–based chain using IBC-Go’s transfer CLI.

Environment

• Cosmos SDK: v0.53.4
• IBC-Go: v10.1.0
• Cobra: v1.9.1
• OS: macOS (arm64)
• Chain type: Any Cosmos SDK–based chain with IBC enabled

Steps to Reproduce

Run the IBC transfer CLI command with fewer than 4 positional arguments.

Example (missing the receiver argument):

<chaind> tx ibc-transfer transfer \
  transfer \
  <src-channel> \
  2000ibc/<denom-hash> \
  --from <wallet-name> \
  --fees <fee-denom> \
  --chain-id <chain-id> \
  --node <rpc-endpoint> \
  -y

The ibc-transfer transfer command is defined to require 4 positional arguments:
[src-port] [src-channel] [receiver] [amount]

Actual Result
The CLI panics with a runtime error instead of returning a validation error:

panic: runtime error: index out of range [3] with length 3

goroutine 1 [running]:
github.com/cosmos/ibc-go/v10/modules/apps/transfer/client/cli.NewTransferTxCmd.func1(...)
    ibc-go/v10/modules/apps/transfer/client/cli/tx.go:57
github.com/spf13/cobra.(*Command).execute(...)
github.com/spf13/cobra.(*Command).Execute(...)
github.com/cosmos/cosmos-sdk/server/cmd.Execute(...)

Expected Result
The CLI should fail gracefully with a clear validation error, for example:
Error: accepts 4 arg(s), received 3

This is the standard behavior when using Cobra argument validation such as:
Args: cobra.ExactArgs(4)

Analysis

• The panic occurs inside:
  ibc-go/v10/modules/apps/transfer/client/cli/tx.go:57

• The command handler accesses args[3] (the 4th positional argument) without ensuring that the argument count has been validated.

• This indicates that:

  • Argument validation is either missing, misconfigured, or bypassed.
  • The handler attempts to index positional arguments before Cobra enforces ExactArgs(4).

As a result, instead of returning a user-friendly error, the CLI crashes.

Impact

• Affects all Cosmos SDK–based chains using this version of IBC-Go.
• Leads to poor UX and unexpected node CLI crashes from simple user input errors.
• Can break scripts or automation that rely on predictable CLI error handling.

Suggested Fix

• Ensure NewTransferTxCmd enforces argument validation using cobra.ExactArgs(4).
• Avoid accessing positional arguments before validation.
• Add a regression test to confirm the command fails gracefully when provided with too few arguments.

Additional Context
This issue is reproducible across chains and is not chain-specific.
The bug appears to originate in the IBC-Go transfer CLI, not in downstream chain implementations.

[linear]

SDK-453

[aljo242]

@andressa-zignaly feel free to open a PR for this!