rumk

A fast Makefile linter written in Rust, built as the Makefile sibling of Rumdl.

Rumk is currently alpha software. Its CLI, configuration model, diagnostics, fixing behavior, and exit codes intentionally follow Rumdl so existing Rumdl users can reuse their workflow.

Features

• Lints individual Makefiles or entire directory trees
• Safely fixes recipe indentation, style-aware .PHONY declarations, and recursive Make invocations
• Parses continued logical statements and nested $(...)/${...} expressions
• Models GNU Make assignment flavors, static patterns, target-specific variables, includes, conditionals, define blocks, custom recipe prefixes, and .ONESHELL
• Builds semantic indexes for variables, references, targets, dependencies, and includes
• Safely evaluates statically knowable variables and conditionals without running recipes, shell commands, or side-effecting Make functions
• Supports GNU substitution references plus common word, path, list, and lazy logical functions
• Resolves expanded include graphs and reports cross-file findings at their real source paths
• Preserves LF/CRLF line endings and final newlines during fixes
• Uses Rumdl-style check, fmt, rule, config, init, and explain commands
• Discovers .rumk.toml upward through the project tree
• Respects .gitignore by default
• Supports rule selection, file globs, per-file ignores, severities, and fix allowlists
• Emits text, flat JSON, and GitHub Actions annotations

Installation

cargo install rumk --locked --version 0.0.5

Or install the native executable from PyPI with a Python tool manager:

uv tool install rumk==0.0.5
# or
pipx install rumk==0.0.5

Rumk is alpha-stage 0.0.x software, so installation names the version explicitly. Release archives and Python wheels cover Linux, macOS, and Windows. GitHub release assets include SHA-256 checksums and build-provenance attestations.

Quick start

# Check Makefiles below the current directory
rumk check

# Check specific files or directories
rumk check Makefile build/

# Apply safe fixes, then fail only if violations remain
rumk check --fix

# Format files with formatter-style exit behavior
rumk fmt

# Preview formatting changes
rumk fmt --diff

# Fail when formatting changes are required
rumk fmt --check

# Inspect rules and effective configuration
rumk rule
rumk rule MK101
rumk config
rumk config get MK101.line-length
rumk config file

Run rumk --help or rumk <command> --help for all options.

Configuration

Create a .rumk.toml file manually or run rumk init:

[global]
dialect = "gnu"
respect-gitignore = true
exclude = ["vendor/**", "generated/**"]
disable = ["MK101"]
fixable = ["MK001"]
include-paths = ["mk"]
predefined-variables = { FROM_CLI = "yes" }
entry-targets = ["all"]

[MK101]
enabled = true
severity = "warning"
line-length = 100
ignore-comments = true
ignore-recipes = true

[MK102]
enabled = true
style = "upper-case"

[MK201]
placement = "auto"

[per-file-ignores]
"vendor/**/*.mk" = ["MK202"]

Configuration discovery checks .rumk.toml, rumk.toml, and .config/rumk.toml while walking upward, stopping at a Git project boundary. Use --config <PATH> for an explicit file or --no-config/--isolated for built-in defaults.

Configurations can inherit another file with extends = "../.rumk.toml"; nested tables are merged, child values win, relative paths resolve from the extending file, and cycles are rejected.

Rules can be suppressed in Make comments without changing project configuration:

# rumk-disable MK202
INSTALL_PREFIX := /usr/local
# rumk-enable MK202

# rumk-disable-next-line MK201
clean:
	rm -rf build

rumk-disable, rumk-enable, rumk-disable-line, and rumk-disable-next-line are supported. Recipe shell comments are not interpreted as Rumk directives.

The original Rumk [rules] and [ignore] configuration sections remain accepted for migration.

include-paths models GNU Make's -I search directories and resolves relative entries from the configuration directory. predefined-variables supplies command-line-style values to safe evaluation and names expected by opt-in rule MK208. That rule intentionally ignores references inside recipes and deferred macro bodies, where command-line parameters and shell values are normal. entry-targets supplies the roots for opt-in reachability rule MK209; the rule stays silent without explicit roots because any Make target may be invoked directly from the command line.

Rule and file selection

Rumk follows Rumdl's selection vocabulary:

rumk check --enable MK001,MK002 .
rumk check --disable MK101 .
rumk check --extend-enable MK202 .
rumk check --exclude "vendor/**,generated/**" .
rumk check --include "src/**" .
rumk check --respect-gitignore=false .
rumk fmt --fixable MK001 .

Exit codes

• 0: success, or all selected violations were fixed
• 1: lint violations, or fmt --check found required changes
• 2: configuration, file access, or other tool error

rumk check fails on any diagnostic by default. Use --fail-on warning, --fail-on error, or --fail-on never to change that policy. rumk fmt exits successfully after formatting even if non-fixable lint diagnostics remain.

Output

Text diagnostics follow Rumdl's familiar form:

Makefile:2:1: [MK001] Recipe must be indented with tab, not spaces [*]

JSON output is a flat array collected across all files:

rumk check --output-format json .

[
  {
    "file": "Makefile",
    "line": 2,
    "column": 1,
    "end_line": 2,
    "end_column": 1,
    "rule": "MK001",
    "message": "Recipe must be indented with tab, not spaces",
    "severity": "error",
    "fixable": true,
    "fix": {
      "range": { "start": 7, "end": 11 },
      "replacement": "\t"
    }
  }
]

The legacy --format spelling remains an alias for --output-format.

Rules

Rules marked default run without configuration. Each rule page documents its behavior, configuration, fixes, edge cases, and the GNU Make, POSIX, or Rumk convention on which it is based.

Syntax

• MK001 — Recipes must use tab indentation (default, fixable)
• MK002 — Invalid variable syntax (default)
• MK003 — Malformed conditional structure (default)
• MK004 — Targets must not mix single- and double-colon declarations (default)
• MK005 — GNU Make special targets must stand alone (default)

Style

• MK101 — Declarative line exceeds the configured maximum length; comments and recipes are ignored by default (default)
• MK102 — Variable naming convention
• MK103 — Target naming convention

Best practices

• MK201 — Conventional non-file targets should be .PHONY; fixes consolidate canonical groups, preserve per-section style, and wrap long declarations (default, fixable)
• MK202 — Avoid hardcoded absolute paths (opt-in)
• MK203 — Recursive Make invocations should use $(MAKE) (default, fixable)
• MK204 — Concrete targets should not declare multiple single-colon recipes (default)
• MK205 — Explicit target dependencies must not form cycles (default)
• MK206 — Required static includes must resolve (default)
• MK207 — Static Makefile includes must not form cycles (default)
• MK208 — Static graph-level variable references must resolve (opt-in)
• MK209 — Targets must be reachable from explicitly configured entries (opt-in)
• MK210 — Explain include expressions blocked by safe evaluation (opt-in)

Development

cargo test --all-targets --all-features
cargo clippy --all-targets --all-features -- -D warnings
cargo fmt --all -- --check
cargo build --release
make check-gnu-fixtures

The product-level compatibility contract is documented in docs/rumdl-compatibility.md.

Contributing

See CONTRIBUTING.md.

License

MIT. See LICENSE.