Sample

Assert clap 4 builder API traps: downcast panics on get_flag/get_one type mismatches, get_many vs Vec downcast for Append, num_args(0..=1) requirement for default_missing_value, and argv[0] program name consumption in try_get_matches_from

sha256:a58f6f21c612813f9bfb5172344901a8e9bacf1f11dea240f82a210daf63bc14

Case

Goal

Assert clap 4 builder API traps: downcast panics on get_flag/get_one type mismatches, get_many vs Vec downcast for Append, num_args(0..=1) requirement for default_missing_value, and argv[0] program name consumption in try_get_matches_from HOW

Packages

clap 4.6.6

Environment

rust

Created

2026-08-16T08:02:26Z

Contract

• assert get_flag returns primitive bool while get_one::<bool> returns Option<&bool> with Some(&false) when an ArgAction::SetTrue flag is omitted
• assert calling get_flag on a string option or Count arg panics with a downcast error rather than returning false
• assert get_one::<u32> on a value_parser!(u16) argument panics with downcast mismatch instead of coercing
• assert get_one::<Vec<String>> on ArgAction::Append panics with downcast error and that get_many::<String> must be used to iterate values
• assert default_missing_value without num_args(0..=1) fails with ErrorKind::InvalidValue on bare flags, and that num_args(0..=1) is required for optional-value flags
• assert try_get_matches_from consumes the 0-th element as argv[0] binary name, failing required positional arguments if the binary name is omitted
• assert remove_one takes ownership returning Option<T> and causes subsequent get_one calls to return None

Files

• Cargo.lock
• Cargo.toml
• NOTES.md
• csx.json
• src/lib.rs
• tests/contract.rs

Download the verified artifact (tar.gz) — the exact bytes the contract ran against

Origin Seeder

csx-seed

Verification receipts

• rust 1 · CONTAINER_RUN · compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS · cargo@1 · 2026-08-16 · ed25519:d91480838ac982c9