ryl Rules Reference¶

A comprehensive reference of all YAML linting rules¶

Introduction¶

ryl implements 27 rules for checking YAML files. This page is a categorised index of every rule with a brief description and a link to its detailed documentation. Each rule page covers what the rule does, why it matters, configuration options, and (where applicable) automatic fix behaviour.

For configuration discovery, presets, and file selection, see Configuration presets. For migrating from yamllint, see Migrating from yamllint.

Rule categories¶

Layout and spacing — whitespace, indentation, line endings, line length
Document structure — document markers, empty values, anchors, tags, keys
Comments — comment placement and spacing
Values — numeric, string, and boolean value formats

Rules that auto-fix are marked with in the Fix column.

Layout and spacing¶

Rule	Description	Fix
`block-scalar-chomping`	Explicit chomping indicator (`-`/`+`) on block scalars.
`braces`	Spaces inside flow mapping braces (`{...}`).
`brackets`	Spaces inside flow sequence brackets (`[...]`).
`colons`	Spaces around mapping colons.
`commas`	Spaces around flow collection commas.
`empty-lines`	Number of consecutive empty lines.
`hyphens`	Spaces after sequence hyphens.
`indentation`	Block indentation, sequence indentation, multi-line strings.
`line-length`	Maximum line length.
`new-line-at-end-of-file`	A trailing newline at end of file.
`new-lines`	Consistent line endings (LF vs CRLF).
`trailing-spaces`	Trailing whitespace at end of lines.
`unicode-line-breaks`	Raw NEL / LS / PS characters (not YAML 1.2 line breaks).

Document structure¶

Rule	Description	Fix
`anchors`	Anchor and alias declarations and usage.
`document-end`	Document end marker `...`.
`document-start`	Document start marker `---`.
`empty-values`	Empty values in mappings and sequences.
`key-duplicates`	Duplicate keys in mappings.
`key-ordering`	Alphabetical or configured ordering of mapping keys.
`merge-keys`	The `<<` merge key (a YAML 1.1 feature removed in 1.2).
`tags`	Unsafe and non-portable YAML tags.

Comments¶

Rule	Description	Fix
`comments`	Spaces after `#` and before inline comments.
`comments-indentation`	Comment alignment with surrounding content.

Values¶

Rule	Description	Fix
`float-values`	Float value formats.
`octal-values`	Octal value formats.
`quoted-strings`	Quoted string styles and when to require quotes.
`truthy`	Truthy values like `yes`, `no`, `on`, `off`.

Severity levels¶

Every rule can be configured to report at either error (the default for most rules) or warning. Errors cause ryl to exit non-zero; warnings are printed but do not fail the run.

Configure the severity inline with the rule:

[rules.line-length]
level = "warning"
max = 120

Enabling and disabling rules¶

Toggle a rule on or off with a top-level string in the [rules] table:

[rules]
truthy = "disable"
key-ordering = "enable"

Enabling a rule without options applies its defaults. To enable every rule, including the ryl-only ones, use ALL:

[rules]
ALL = "enable"
truthy = "disable"

[rules.line-length]
max = 120

Each rule then runs with its own defaults at level error. An explicit entry for a rule wins over ALL wherever it appears in the table. New rules arrive with ryl upgrades, so ALL can start reporting new diagnostics after an update. ALL is TOML-only; yamllint-compatible YAML config rejects it.

ryl check --enable <RULES> picks the rules from the command line instead: comma-separated rule IDs or ALL, and the flag can be repeated. It replaces the config's selection, so only the listed rules run. A listed rule keeps the options and level the config gives it, and runs at its defaults if the config disables it or does not mention it. ignore, per-file-ignores and inline directives still apply. The flag works without any config file:

ryl check --enable ALL .
ryl check --enable truthy,line-length .

The built-in default and relaxed presets cover the common starting points (the empty preset is YAML-extends: only, with no usable TOML form); see Configuration presets.

To switch rules off for part of a file with # ryl disable / # yamllint disable comments, see Inline directives.

Automatic fixing¶

The --fix flag applies safe fixes for rules marked with above:

ryl check --fix .

Control which rules apply fixes with a [fix] table:

[fix]
fixable = ["ALL"]
unfixable = ["comments"]