postcss 8.5.26: Warning

Clean-room public code sample — generation instructions

Write a brand-new, minimal, self-contained code sample in this clean-room directory.
Do not copy, paraphrase, or reference any existing project source. Work only from this spec.

A csx.json manifest scaffold already exists. Do not recreate it from memory. Preserve its case.goal, packages and symbols; fill its empty case.contract with exact assertions and correct its environment, commands and verifierAdapter for the files you generate.

Goal: verify Warning in pkg:npm/postcss@8.5.26
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/postcss@8.5.26
Demonstrate these symbols/APIs:
  - Warning

Rules:
  - One focused purpose; the smallest project that proves the goal.
  - Include a contract test (test/contract.*) that runs OFFLINE and exits 0 exactly when the goal behavior works.
  - Pin every dependency with a lockfile so resolution is reproducible.
  - No secrets, credentials, or tokens. No real URLs (only example.com or localhost). No absolute paths.
  - No personal names, emails, company names, or project identifiers of any kind.
  - No binaries and no generated output (node_modules, dist, target, venv, .git, .env).
  - Keep it under 200 files and 256KB packed.

{"case":{"caseId":"case:sha256:e419d0c185e1463246045bb6479be6239e2656c39d8994e415453e210e9404d7","contract":["assert new postcss.Warning constructs warning object with type 'warning', custom text, and copies optional metadata","assert Warning automatically derives line, column, endLine, and endColumn coordinates from AST node source ranges","assert Warning calculates line and column offsets when word or index options are specified for an AST node","assert warning.toString formats messages based on presence of AST node, plugin name, and source location","assert result.warn instantiates Warning with active plugin context and appends it to result messages and warnings"],"goal":"verify Warning in pkg:npm/postcss@8.5.26","kind":"HOW","packages":["pkg:npm/postcss@8.5.26"],"schemaVersion":1,"symbols":["Warning"]},"contractCommand":["node","test/contract.mjs"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"npm","executionContext":"node","language":"javascript","libc":"glibc","libcVersion":"2.39","moduleSystem":"cjs","os":"linux","osVersionBucket":"24","packageManager":"npm","runtime":"node","runtimeVersion":"22.23.2","schemaVersion":1},"license":"MIT-0","packages":["pkg:npm/postcss@8.5.26"],"schemaVersion":1,"subject":"pkg:npm/postcss@8.5.26","symbols":["Warning"],"verifierAdapter":"node-typescript@1"}

{
  "name": "sample-postcss-warning",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-postcss-warning",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "postcss": "8.5.26"
      }
    },
    "node_modules/nanoid": {
      "version": "3.3.18",
      "resolved": "https://registry.npmjs.org/nanoid/-/nanoid-3.3.18.tgz",
      "integrity": "sha512-DTg4MJbGMWkfi6VZFdNt2/caMbQy4Ou+Op/hJQvGEWcnVfoA1QA+xzRKAzw9jD6+GVOOeYr/mIcuDSdug6F6+w==",
      "funding": [
        {
          "type": "github",
          "url": "https://github.com/sponsors/ai"
        }
      ],
      "license": "MIT",
      "bin": {
        "nanoid": "bin/nanoid.cjs"
      },
      "engines": {
        "node": "^10 || ^12 || ^13.7 || ^14 || >=15.0.1"
      }
    },
    "node_modules/picocolors": {
      "version": "1.1.1",
      "resolved": "https://registry.npmjs.org/picocolors/-/picocolors-1.1.1.tgz",
      "integrity": "sha512-xceH2snhtb5M9liqDsmEw56le376mTZkEX/jEb/RxNFyegNul7eNslCXP9FDj/Lcu0X8KEyMceP2ntpaHrDEVA==",
      "license": "ISC"
    },
    "node_modules/postcss": {
      "version": "8.5.26",
      "resolved": "https://registry.npmjs.org/postcss/-/postcss-8.5.26.tgz",
      "integrity": "sha512-u82N74LFzG8ca+dD8puPnplTXoGH4fTPpVGuIbt36G3qvNlkvfD0lEAZSxaly3KX8TS/L1A1gsCEmvKmBcVbkQ==",
      "funding": [
        {
          "type": "opencollective",
          "url": "https://opencollective.com/postcss/"
        },
        {
          "type": "tidelift",
          "url": "https://tidelift.com/funding/github/npm/postcss"
        },
        {
          "type": "github",
          "url": "https://github.com/sponsors/ai"
        }
      ],
      "license": "MIT",
      "dependencies": {
        "nanoid": "^3.3.17",
        "picocolors": "^1.1.1",
        "source-map-js": "^1.2.1"
      },
      "engines": {
        "node": "^10 || ^12 || >=14"
      }
    },
    "node_modules/source-map-js": {
      "version": "1.2.1",
      "resolved": "https://registry.npmjs.org/source-map-js/-/source-map-js-1.2.1.tgz",
      "integrity": "sha512-UXWMKhLOwVKb728IUtQPXxfYU+usdybtUrK/8uGE8CQMvrhOpwvzDBwj0QhSL7MQc7vIsISBG8VQ8+IDQxpfQA==",
      "license": "BSD-3-Clause",
      "engines": {
        "node": ">=0.10.0"
      }
    }
  }
}

{
  "name": "sample-postcss-warning",
  "version": "1.0.0",
  "type": "module",
  "license": "MIT-0",
  "dependencies": {
    "postcss": "8.5.26"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify Warning in pkg:npm/postcss@8.5.26",
  "kind": "HOW",
  "packages": [
    "pkg:npm/postcss@8.5.26"
  ],
  "symbols": [
    "Warning"
  ]
}

import assert from 'node:assert/strict';
import { createRequire } from 'node:module';

const require = createRequire(import.meta.url);
const postcss = require('postcss');

// 1. assert new postcss.Warning constructs warning object with type 'warning', custom text, and copies optional metadata
{
  const warning = new postcss.Warning('Deprecated property used', {
    plugin: 'postcss-custom-linter',
  });
  assert.equal(warning.type, 'warning');
  assert.equal(warning.text, 'Deprecated property used');
  assert.equal(warning.plugin, 'postcss-custom-linter');
  assert.equal(warning.node, undefined);
  assert.equal(warning.line, undefined);
  assert.equal(warning.column, undefined);
}

// 2. assert Warning automatically derives line, column, endLine, and endColumn coordinates from AST node source ranges
{
  const css = 'a {\n  color: red;\n  opacity: 0.5;\n}';
  const root = postcss.parse(css);
  const decl = root.nodes[0].nodes[1]; // opacity: 0.5
  const warning = new postcss.Warning('Low opacity value', {
    node: decl,
    plugin: 'postcss-validator',
  });
  assert.equal(warning.node, decl);
  assert.equal(warning.line, 3);
  assert.equal(warning.column, 3);
  assert.equal(warning.endLine, 3);
  assert.equal(warning.endColumn, 16);
}

// 3. assert Warning calculates line and column offsets when word or index options are specified for an AST node
{
  const css = '.btn {\n  background: red blue;\n}';
  const root = postcss.parse(css);
  const decl = root.first.first; // background: red blue;

  const wordWarning = new postcss.Warning('Unknown color token', {
    node: decl,
    word: 'blue',
    plugin: 'color-checker',
  });
  assert.equal(wordWarning.word, 'blue');
  assert.equal(wordWarning.line, 2);
  assert.equal(wordWarning.column, 19);
  assert.equal(wordWarning.endLine, 2);
  assert.equal(wordWarning.endColumn, 23);

  const indexWarning = new postcss.Warning('Indexed issue', {
    node: decl,
    index: 5,
    plugin: 'index-checker',
  });
  assert.equal(indexWarning.index, 5);
  assert.equal(indexWarning.line, 2);
  assert.equal(indexWarning.column, 8);
}

// 4. assert warning.toString formats messages based on presence of AST node, plugin name, and source location
{
  // Plain warning without node or plugin
  const plainWarning = new postcss.Warning('Generic warning message');
  assert.equal(plainWarning.toString(), 'Generic warning message');

  // Warning with plugin but no node
  const pluginWarning = new postcss.Warning('Config deprecated', {
    plugin: 'postcss-config-checker',
  });
  assert.equal(pluginWarning.toString(), 'postcss-config-checker: Config deprecated');

  // Warning with node and source
  const css = '.alert {\n  display: inline;\n}';
  const root = postcss.parse(css);
  const decl = root.first.first;
  const nodeWarning = new postcss.Warning('Use flex instead', {
    node: decl,
    plugin: 'layout-linter',
  });
  assert.equal(
    nodeWarning.toString(),
    'layout-linter: <css input>:2:3: Use flex instead'
  );
}

// 5. assert result.warn instantiates Warning with active plugin context and appends it to result messages and warnings
{
  const testPlugin = {
    postcssPlugin: 'test-warning-emitter',
    Declaration(decl, { result }) {
      if (decl.prop === 'margin') {
        const warn = result.warn('Margin found', { node: decl, word: 'margin' });
        assert.ok(warn instanceof postcss.Warning);
      }
    },
  };
  const css = 'div { margin: 10px; }';
  const result = postcss([testPlugin]).process(css);
  const warnings = result.warnings();
  assert.equal(warnings.length, 1);
  const w = warnings[0];
  assert.ok(w instanceof postcss.Warning);
  assert.equal(w.plugin, 'test-warning-emitter');
  assert.equal(w.text, 'Margin found');
  assert.equal(w.line, 1);
  assert.equal(w.column, 7);
  assert.equal(w.word, 'margin');
  assert.equal(w.toString(), 'test-warning-emitter: <css input>:1:7: Margin found');
}