tools-mutation-prove

HARVEST-PLAYBOOK Sec13.3 mutation proof: mutate -> must-go-red test -> byte-identical restore.

What it is for

tools-mutation-prove -- HARVEST-PLAYBOOK Sec13.3 mutation proof, ported from scripts/harvest/tools-mutation-prove.sh.

Backs up FILE (never git checkout), applies a single-mechanism MUTATION, runs TEST, requires it to go RED (a surviving mutation = vacuous test = BLOCK), then restores FILE and verifies the restore is byte-identical (direct byte comparison).

Usage: tools-mutation-prove <file> <test-cmd> <mutate-cmd>

Exit codes (mirror the original bash script): 0 - mutation proven (test went red, file restored byte-identical) 1 - mutation survived (test stayed green) -- vacuous test, BLOCK 2 - usage error / target file does not exist 3 - mutate-cmd did not change the file (pattern did not match) 4 - restore did not come back byte-identical after a kill

• - mutate-cmd itself failed; its own exit code is propagated

Capabilities

RestoreGuard

tools-mutation-prove -- HARVEST-PLAYBOOK Sec13.3 mutation proof, ported from

How to use it

No examples/ target and no doctest in this crate's rustdoc. The tests listed under Verification are the closest executable usage.

Module structure

No public modules: the crate root is its whole surface.

Public surface

`crate root`

No pub use re-exports: every item above is declared in this crate.

Boundary

Depends on no other workspace tier.

Shares tier tools with 84 other crates: tools-advisory-reach, tools-archive-guard, tools-artifact-scaffold, tools-ask-ai-core, tools-ask-ais, tools-ask-gemini, tools-book, tools-book-report, … (84 total).

_What this crate deliberately does NOT own is a judgment. No committed registry records one for it, so none is stated here._

Where it sits

Dependencies

Runtime, from outside the workspace.

Development. None.

Build. None.

Depended on by. Nothing in this workspace.

Feature flags

No Cargo features are defined: every capability is unconditional, so no consumer can receive a half-wired crate.

Targets

Error model

No public error type was detected: no public item declares a type named *Error, and no public signature returns one.

Operational characteristics

No unsafe block, unsafe fn, unsafe impl or unsafe trait was found by the parser anywhere in this crate's source.

Configuration

No environment variable is read with a literal name anywhere in this crate. A variable whose key is computed at run time cannot be listed here, and is not claimed to be absent.

Related capabilities

No workspace crate depends on this one.

Verification

What the tests establish, by name:

• backup_candidate_path_differs_across_attempts — src/main.rs
• create_backup_and_manual_restore_round_trip — src/main.rs
• restore_guard_does_nothing_when_disarmed — src/main.rs
• restore_guard_restores_on_drop_when_armed — src/main.rs
• run_shell_captured_reports_failure — src/main.rs
• run_shell_captured_reports_success_and_output — src/main.rs
• run_shell_captured_truncates_to_cap — src/main.rs
• run_shell_inherit_reports_nonzero_exit_code — src/main.rs
• run_shell_inherit_reports_success — src/main.rs
• tail_lines_empty_input_yields_empty_string — src/main.rs
• tail_lines_keeps_everything_when_input_is_shorter_than_n — src/main.rs
• tail_lines_keeps_last_n_when_input_is_longer — src/main.rs
• truncate_last_bytes_exact_cap_is_unchanged — src/main.rs
• truncate_last_bytes_is_a_no_op_when_under_cap — src/main.rs
• truncate_last_bytes_keeps_only_the_tail_when_over_cap — src/main.rs

Documentation coverage

pie showData
    title Public items with rustdoc
    "Documented" : 0
    "No rustdoc detected" : 1

Metrics

pie showData
    title Public API by kind
    "method" : 1

pie showData
    title Rust source composition
    "Code" : 284
    "Blank or comment" : 100

Generation

Rendered by tools-corpus corpus readme from repository evidence alone, renderer schema 2, lexicon current. No model, network service or database was consulted. Regenerate with tools-corpus corpus readme --write; verify with --check.