Existing formatters

[epage]

Post what exists

[epage]

toml-fmt

• uses the default formatting of toml

[epage]

dprint-plugin-toml

• uses taplo

Config

• lineWidth
• indentWidth
• useTabs
• newLineKind
• comment.forceLeadingSpace
• cargo.applyConventions

Cargo conventions

• package sort order: custom
• dependency sort order: alphabetical

[package] sort order:

    ("version", "name") => Ordering::Greater,
    ("name", _) => Ordering::Less,
    ("version", _) => Ordering::Less,
    ("description", _) => Ordering::Greater,
    (_, "name") => Ordering::Greater,
    (_, "version") => Ordering::Greater,
    (_, "description") => Ordering::Less,

[epage]

rust-lang/rustfmt#5240

[epage]

cargo-toml-format

Sections

• package section should always be at the top.
• package section order as it is defined in the manifest is maintained.
• Section header and the first following keys should NOT be separated by space.
• Sections are separated by a single newline.

Comments

• If the comment is inline, on the same line as an item, it should be separated from the item by one space.
• Arrays where each line is wrapped on a new line may contain comments at the line ending to elaborate on certain array items.
• Arrays where each line is wrapped on a new line may contain comments as entries to elaborate on certain arrray items.

Keys

• Keys within sections have no spaces in between them except for the usecase of grouping.
• Groups in sections are defined by a single white space.
• Keys may not contain quotes.
• Keys are separated from a value by =
• Keys may not contain quotes (unless it is required for a particular reason)
• Keys are sorted alphabetically within each section, except for the [package] section.
• Empty spaces are stripped at the start and end of each line.

Line Length Wrap

• Arrays wrap line when longer than configurable length.
• For table values, such as a crate dependency with a path, write the entire table using curly braces and commas on the same line as the key if it fits. If the entire table does not fit on the same line as the key, separate it out into a separate section with key-value pairs.
• Within the description field, wrap text at 80 columns
• Use multiline strings rather than \n.

Field Restrictions

• The license field, if present, must contain a valid SPDX expression, using valid SPDX license names. (As an exception, by widespread convention, the license field may use / in place of OR; for example, MIT/Apache-2.0.) [^6]

• The homepage, documentation, and repository field, if present, must consist of a single URL, including the scheme (e.g. https://example.org/, not just example.org.)

• The name field must use only alphanumeric characters or - or _, and cannot be empty. Note that cargo new and cargo init impose some additional restrictions on the package name, such as enforcing that it is a valid Rust identifier and not a keyword. crates.io imposes even more restrictions, such as enforcing only ASCII characters, not a reserved name, not a special Windows name such as "nul", is not too long, etc. [^3]

• The edition, if present, field may only contain one of the following: 2015, 2018, and 2021 [^4]

• The rust-version, if present, must be a bare version number with two or three components; it cannot include semver operators or pre-release identifiers. [^5]

• The readme, and build, field, if present, must be an existing file.

• The keywords field its keyword must be ASCII text, start with a letter, and only contain letters, numbers, _ or -, and have at most 20 characters. [^7]

• The categories field its categories, if present, should match one of the strings available at https://crates.io/category_slugs, and must match exactly.

• The publish field, if present, must be a boolean or array with registry links. [^8]

[epage]

cargo-toml-lint

• tables are hierarchical
• dependencies and dev-dependencies are sorted
• [[test]] are sorted
• trailing whitespace

[epage]

cargo-sort

# trailing comma in arrays
always_trailing_comma = false
# trailing comma when multi-line
multiline_trailing_comma = true
# the maximum length in bytes of the string of an array object
max_array_line_len = 80
# number of spaces to indent
indent_count = 4
# space around equal sign
space_around_eq = true
# remove all the spacing inside the array
compact_arrays = false
# remove all the spacing inside the object
compact_inline_tables = false
trailing_newline = true
# is it ok to have blank lines inside of a table
# this option needs to be true for the --grouped flag
key_value_newlines = true
allowed_blank_lines = 1
# windows style line endings
crlf = false
# The user specified ordering of tables in a document.
# All unspecified tables will come after these.
table_order = [
    "package",
    "workspace",
    "lib",
    "bin",
    "features",
    "dependencies",
    "build-dependencies",
    "dev-dependencies",
]

[epage]

cargo-tomlfmt

• sorts table entries
• switches to default styling

[epage]

tombi

[format]
[format.rules]
array-bracket-space-width = 0
array-comma-space-width = 1
date-time-delimiter = "T"
indent-style = "space"
indent-sub-tables = false
indent-table-key-value-pairs = false
indent-width = 2
inline-table-brace-space-width = 1
inline-table-comma-space-width = 1
key-value-equals-sign-alignment = false
key-value-equals-sign-space-width = 1
line-ending = "lf"
line-width = 80
string-quote-style = "double"
trailing-comment-alignment = false
trailing-comment-space-width = 2

[lint]
[lint.rules]
dotted-keys-out-of-order = "warn"
key-empty = "warn"
tables-out-of-order = "warn"

[lsp]
code-action.enabled = true
completion.enabled = true
diagnostics.enabled = true
document-link.enabled = true
formatting.enabled = true
goto-declaration.enabled = true
goto-definition.enabled = true
goto-type-definition.enabled = true
hover.enabled = true
workspace-diagnostic.enabled = true