madr/no-duplicate-numbering

A cross-file project rule that reports when two or more ADRs share the same NNNN- number prefix in their basename.

The runner pre-parses every ADR file once and hands them all to the rule in a single check() call. The rule reads the leading four digits (^(\d{4})-) from each basename, groups files by number, and emits a diagnostic on every member of any duplicate group — so a reviewer sees the conflict in each affected file’s output, not just one.

What it checks

duplicateNumber — two or more files resolve to the same NNNN prefix. Message: ADR number <number> is used by multiple files: <paths>, with data.number and data.paths (the conflicting paths, comma-joined). One diagnostic is emitted per file in the group.

Files whose basename does not start with NNNN- (e.g. template.md, README.md, 0001invalid.md without a hyphen) are silently ignored — madr/filename-format is responsible for those.

Examples

Valid

docs/adr/
  0001-mise.md
  0002-aube.md
  0003-oxc.md

No diagnostics.

Invalid

docs/adr/
  0001-foo.md
  0001-bar.md

Emits 2 diagnostics (one per file), both duplicateNumber with data.number: '0001' and data.paths: '0001-foo.md, 0001-bar.md'.

docs/adr/
  0001-a.md
  0001-b.md
  0001-c.md
  0002-x.md
  0002-y.md

Emits 5 diagnostics: 3 for 0001, 2 for 0002.

Options

This rule has no options.

import { defineConfig } from 'madr-lint';

export default defineConfig({
  rules: {
    'madr/no-duplicate-numbering': 'error',
  },
});

MADR version compatibility

Version	Applies
v2	yes
v3	yes
v4	yes

The filename numbering convention is identical across MADR versions.

When to disable

There is essentially no reason to disable this rule. If two ADRs share a number, one of them is wrong by definition.

Like all rules, this rule can be suppressed inline — see Suppressing rules.