Configuration File¶

go-mutesting can be configured via a YAML file. Pass it with --config <path>. No default config file is loaded automatically.

A JSON Schema for editor validation and auto-completion is at schema/config-schema.json. Enable it in VS Code and other YAML-aware editors with a header comment:

# yaml-language-server: $schema=https://raw.githubusercontent.com/jonbaldie/go-mutesting/master/schema/config-schema.json
skip_without_test: true
min_msi: 70

Schema¶

skip_without_test: true
skip_with_build_tags: true
json_output: false
html_output: false
silent_mode: false
min_msi: 0
min_covered_msi: 0
exclude_dirs: []
disable_mutators: []
enable_mutators: []
ignore_source_lines: []

Fields¶

Field	Type	Default	Description
`skip_without_test`	bool	`true`	Skip source files that have no corresponding `_test.go` file
`skip_with_build_tags`	bool	`true`	Skip test files that have build tags
`json_output`	bool	`false`	Write a full mutation report to `report.json`
`html_output`	bool	`false`	Write an HTML report to `go-mutesting-report.html`
`silent_mode`	bool	`false`	Suppress per-mutation output (summary only)
`min_msi`	float	`0`	Minimum overall MSI (0–100); `0` disables the gate
`min_covered_msi`	float	`0`	Minimum covered-code MSI (0–100); `0` disables the gate
`exclude_dirs`	[]string	`[]`	Directory path prefixes to exclude from mutation
`disable_mutators`	[]string	`[]`	Mutator names to disable. Merged with `--disable` CLI flags (union). Supports trailing-`` wildcard, e.g. `arithmetic/`. Run `go-mutesting --list-mutators` for all names.
`enable_mutators`	[]string	`[]`	Allowlist: if non-empty, only matching mutators run. Supports trailing-`*` wildcard. `--disable` can still exclude entries from this list.
`ignore_source_lines`	[]string	`[]`	List of regexes. Any source line matching one of these patterns is skipped entirely. Useful for suppressing mutations on generated code or boilerplate.

Notes¶

CLI flags override config file values.
Unknown keys in the config file cause an error (strict parsing).
exclude_dirs values are matched as path prefixes, not globs. For example, vendor excludes any path starting with vendor.

Mutator control¶

enable_mutators is an allowlist: when set, only the listed mutators run. disable_mutators is then applied on top as a denylist, so you can narrow an allowlist further. CLI --disable is always merged with disable_mutators.

Disable an entire category using a trailing *:

disable_mutators:
  - arithmetic/*
  - numbers/float-negate

Run only a specific category:

enable_mutators:
  - branch/*

Combine — enable a category but suppress one noisy member:

enable_mutators:
  - expression/*
disable_mutators:
  - expression/context-nil

Run go-mutesting --list-mutators to see all available names.

Shell quoting: when passing wildcard patterns via --disable on the command line, always quote them to prevent your shell from expanding * as a filename glob: --disable 'arithmetic/*'. In config files, no quoting is needed.

Example¶

skip_without_test: true
min_msi: 70
min_covered_msi: 80
exclude_dirs:
  - vendor
  - testdata