unique_by

No two files matching select may share the value of key (a path template; tokens {path}/{dir}/{basename}/{stem}/{ext}/{parent_name}). Catches basename collisions across subdirectories. With case_insensitive: true the key is folded to lowercase before grouping, so README.md and readme.md collide — the case-insensitive-filesystem hazard (Windows / macOS).

Options

Option	Type	Required	Default	Description
case_insensitive	boolean		false	Fold the key to lowercase before grouping, so keys that collide only under case-folding count as duplicates - the case-insensitive-filesystem hazard (Windows / macOS).
key	string		{basename}	Path-template producing a key per matched file. Default: {basename}.
select	string	yes		Glob selecting the files to deduplicate.

Plus the common level, id, and when fields. This rule analyses the whole repository, so it takes no paths. This table is generated from the JSON Schema; option types and defaults are authoritative.

Example

Two files colliding on the same stem

The rule fires on this repository:

a/
a/util.rs
b/
b/util.rs
c/
c/other.rs

a/util.rs

pub fn a() {}

b/util.rs

pub fn b() {}

c/other.rs

pub fn c() {}

With this .alint.yml:

version: 1
rules:
  - id: unique-rs-stems
    kind: unique_by
    select: "**/*.rs"
    key: "{stem}"
    level: warning

alint check reports:

--- a/util.rs ------------------------------------------------------------------
  !  warning  unique-rs-stems
              duplicate key "util" shared by 2 file(s): a/util.rs, b/util.rs

Summary (1 violation):
  ! 1 warning
  0 passing * 1 failing

Every file has a distinct stem

This repository is compliant:

src/
src/alpha.rs
src/beta.rs
src/gamma.rs

With this .alint.yml:

version: 1
rules:
  - id: unique-rs-stems
    kind: unique_by
    select: "**/*.rs"
    key: "{stem}"
    level: warning

alint check reports:

v All 1 rule(s) passed.