Config file

Many options for cargo-mutants can be set in a config file. By default, the config file is read from .cargo/mutants.toml in the source tree root.

It's recommended that the config file be checked in to the source tree with values that will allow developers to run cargo mutants with no other options.

--no-config can be used to disable reading the configuration file.

--config FILE can be used to read configuration from a custom file instead of the default location. This is useful for having different configurations for different scenarios (e.g., CI/CD, development, specific testing requirements).

For a full list of keys, see https://github.com/sourcefrog/cargo-mutants/blob/main/src/config.rs.

An example config file with detailed comments can be found at examples/custom_config.toml.

Merging config and command-line options

When options are specified in both the config file and the command line, the command line options take precedence.

For options that take a list of values, values from the configuration file are appended to values from the command line.

Config file schema

A JSON Schema describes the fields in the config file and can be used by many text editors to provide autocompletion and validation.

A recent version of the schema is available at https://json.schemastore.org/cargo-mutants-config.json.

To generate the schema, run:

cargo mutants --emit-schema=config > config-schema.json