CLI panics with "attempt to add with overflow" when building tx for account at INT64_MAX sequence

[leighmcculloch]

What version are you using?

stellar 25.1.0

What did you do?

Built a transaction for an account whose sequence number is at INT64_MAX (9223372036854775807).

Any account holder can bump their sequence to INT64_MAX using the bump_sequence operation, so this condition is achievable on any network.

Reproduction steps:

# 1. Generate and fund account
stellar keys generate --fund test-account
# 2. Bump sequence to INT64_MAX
stellar tx new bump-sequence --source test-account --bump-to 9223372036854775807
# 3. Try to build another tx (bump-to 0 is a no-op, should succeed) — triggers panic
stellar tx new bump-sequence --source test-account --bump-to 0

What did you expect to see?

A graceful error message such as "account sequence number is at maximum, no further transactions can be submitted from this account".

What did you see instead?

The CLI panics (crashes):

thread 'main' panicked at cmd/soroban-cli/src/config/mod.rs:166:12:
attempt to add with overflow

Backtrace:

0: __rustc::rust_begin_unwind
1: core::panicking::panic_fmt
2: core::panicking::panic_const::panic_const_add_overflow
3: soroban_cli::commands::tx::args::Args::handle_and_print::{{closure}}
4: soroban_cli::commands::tx::Cmd::run::{{closure}}
5: soroban_cli::commands::Root::run::{{closure}}
6: tokio::runtime::park::CachedParkThread::block_on
7: tokio::runtime::context::runtime::enter_runtime
8: soroban_cli::cli::main