mutants.toml

# cargo-mutants configuration
# https://mutants.rs/
#
# This file was removed in commit 44a02ae (Apr 2026) because the hooks
# and plugins integration tests tripped Linux `ETXTBSY` races under
# cargo-mutants' parallel worker fleet, making every baseline run
# flaky and blocking mutation testing entirely. The ETXTBSY race is
# an intra-process `posix_spawn` fd-inheritance bug
# (rust-lang/rust#114554) that was masked but never fixed.
#
# The race is now handled in production code at
# `crate::io::spawn_with_etxtbsy_retry`, which the hook runner and
# plugin manager both route through. Mutation testing is therefore
# re-enabled — this file was restored from the pre-removal revision
# and is kept in sync with the shape of the current test suite.
#
# If mutation testing flakes on `ETXTBSY` again in the future, do not
# remove this file. Investigate whether the retry wrapper is still
# wired into every subprocess-spawning code path; flaking here is a
# signal that a new spawn site skipped the wrapper.

# Timeout for each mutant test run (seconds)
timeout = 60

# Timeout multiplier for debug builds
build_timeout_multiplier = 2

# Number of parallel jobs (0 = use all CPUs)
jobs = 0

# Continue testing other mutants after one fails
continue_after_failure = true

# Shuffle mutants for better parallelism
shuffle = true

# Minimum test timeout (seconds)
minimum_test_timeout = 20

# Exclude files that don't benefit from mutation testing
exclude_globs = [
    "src/main.rs",           # Entry point only
    "tests/**",              # Test code itself
    "xtask/**",              # Build automation
    "benches/**",            # Benchmarks
    "examples/**",           # Examples
]

# Exclude specific functions by regex
exclude_re = [
    "^impl.*Display",        # Display implementations
    "^impl.*Debug",          # Debug implementations
    "^impl.*Default",        # Default implementations
    "^impl.*From<",          # From trait implementations
    "^impl.*Error",          # Error trait implementations
    "^main$",                # main function
    "^new$",                 # Simple constructors
    "::log_",                # Logging functions
    "::trace_",              # Tracing functions
]

# Mutant error values to use when replacing return values
[error_values]
# For Option<T>
"Option" = ["None"]
# For Result<T, E>
"Result" = ["Err(Default::default())"]
# For bool
"bool" = ["false", "true"]