Add @blueprintjs/stylelint-plugin package and no-prefix-literal rule

.stylelintrc

@@ -3,7 +3,11 @@
     "stylelint-config-palantir",
     "stylelint-config-palantir/sass.js"
   ],
+  "plugins": [
+    "@blueprintjs/stylelint-plugin"
+  ],
   "rules": {
+    "@blueprintjs/no-prefix-literal": true,
     "declaration-empty-line-before": null,
     "indentation": [2, {
       "ignore": ["value"]

packages/stylelint-plugin/.eslintrc.json

@@ -0,0 +1,9 @@
+{
+    "root": true,
+    "extends": ["../../.eslintrc.js"],
+    "rules": {
+        "no-duplicate-imports": "off",
+        "@typescript-eslint/no-duplicate-imports": ["error"]
+    },
+    "ignorePatterns": ["node_modules", "dist", "lib", "fixtures", "coverage", "__snapshots__", "generated"]
+}

packages/stylelint-plugin/README.md

@@ -0,0 +1,69 @@
+<img height="204" src="https://cloud.githubusercontent.com/assets/464822/20228152/d3f36dc2-a804-11e6-80ff-51ada2d13ea7.png">
+
+# [Blueprint](http://blueprintjs.com/) [stylelint](https://stylelint.io/) plugin
+
+Blueprint is a React UI toolkit for the web.
+
+This package contains the [stylelint](https://stylelint.io/) plugin for Blueprint. It provides custom rules which are useful when developing against Blueprint libraries.
+
+**Key features:**
+
+-   [Blueprint-specific rules](#Rules) for use with `@blueprintjs` components.
+
+## Installation
+
+```
+yarn add --dev @blueprintjs/stylelint-plugin
+```
+
+## Usage
+
+Simply add this plugin in your `.stylelintrc` file and then pick the rules that you need. The plugin includes Blueprint-specific rules which enforce semantics particular to usage with `@blueprintjs` packages, but does not turn them on by default.
+
+`.stylelintrc`
+
+```json
+{
+    "plugins": [
+        "@blueprintjs/stylelint-plugin"
+    ],
+    "rules": {
+        "@blueprintjs/no-prefix-literal": true
+    }
+}
+```
+
+## Rules
+
+### `@blueprintjs/no-prefix-literal` (autofixable)
+
+Enforce usage of the `ns` constant over namespaced string literals.
+
+The `@blueprintjs` package exports a `ns` CSS variable which contains the prefix for the current version of Blueprint (`bp3` for Blueprint 3, `bp4` for Blueprint 4, and etc). Using the variable instead of hardcoding the prefix means that your code will still work when new major version of Blueprint is released.
+
+```json
+{
+    "rules": {
+        "@blueprintjs/no-prefix-literal": true
+    }
+}
+```
+
+```diff
+-.bp3-button > div {
+-    border: 1px solid black;
+-}
++ @import "~@blueprntjs/core/lib/scss/variables";
++
++.#{$ns}-button > div {
++    border: 1px solid black;
++}
+```
+
+Optional secondary options:
+
+- `disableFix: boolean` - if true, autofix will be disabled
+- `variablesImportPath: { less?: string, sass?: string }` - can be used to configure a custom path for importing Blueprint variables when autofixing.
+
+
+### [Full Documentation](http://blueprintjs.com/docs) | [Source Code](https://github.com/palantir/blueprint)

packages/stylelint-plugin/package.json

@@ -0,0 +1,33 @@
+{
+    "name": "@blueprintjs/stylelint-plugin",
+    "version": "0.0.0",
+    "description": "Stylelint rules for use with @blueprintjs packages",
+    "main": "lib/index.js",
+    "scripts": {
+        "compile": "tsc -p src/",
+        "lint": "run-p lint:es",
+        "lint:es": "es-lint",
+        "lint-fix": "es-lint --fix",
+        "test": "mocha test/index.js"
+    },
+    "dependencies": {
+        "postcss": "^7.0.35",
+        "postcss-selector-parser": "^6.0.5"
+    },
+    "peerDependencies": {
+        "stylelint": "^13.0.0"
+    },
+    "devDependencies": {
+        "@blueprintjs/node-build-scripts": "^1.5.0",
+        "@types/stylelint": "^9.10.1",
+        "mocha": "^8.2.1",
+        "typescript": "^4.1.2"
+    },
+    "repository": {
+        "type": "git",
+        "url": "git@github.com:palantir/blueprint.git",
+        "directory": "packages/stylelint-plugin"
+    },
+    "author": "Palantir Technologies",
+    "license": "Apache-2.0"
+}

packages/stylelint-plugin/src/index.ts

@@ -0,0 +1,18 @@
+/* Copyright 2020 Palantir Technologies, Inc. All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.*/
+
+import noPrefixLiteral from "./rules/no-prefix-literal";
+
+// eslint-disable-next-line import/no-default-export
+export default [noPrefixLiteral];

packages/stylelint-plugin/src/rules/no-prefix-literal.ts

@@ -0,0 +1,147 @@
+/*
+ * Copyright 2021 Palantir Technologies, Inc. All rights reserved.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { Root, Result } from "postcss";
+import parser from "postcss-selector-parser";
+import stylelint from "stylelint";
+import type { Plugin, RuleTesterContext } from "stylelint";
+
+import { checkImportExists } from "../utils/checkImportExists";
+import { insertImport } from "../utils/insertImport";
+
+const ruleName = "@blueprintjs/no-prefix-literal";
+
+const messages = stylelint.utils.ruleMessages(ruleName, {
+    expected: (unfixed: string, fixed: string) => `Use the \`${fixed}\` variable instead of the \`${unfixed}\` literal`,
+});
+
+const bannedPrefixes = ["bp1", "bp2", "bp3", "bp4"];
+
+interface Options {
+    disableFix?: boolean;
+    variablesImportPath?: Partial<Record<Exclude<CssSyntax, CssSyntax.OTHER>, string>>;
+}
+
+// eslint-disable-next-line import/no-default-export
+export default stylelint.createPlugin(ruleName, ((
+    enabled: boolean,
+    options: Options | undefined,
+    context: RuleTesterContext,
+) => (root: Root, result: Result) => {
+    if (!enabled) {
+        return;
+    }
+
+    const validOptions = stylelint.utils.validateOptions(
+        result,
+        ruleName,
+        {
+            actual: enabled,
+            optional: false,
+            possible: [true, false],
+        },
+        {
+            actual: options,
+            optional: true,
+            possible: {
+                disableFix: [true, false],
+                variablesImportPath: (obj: unknown) => {
+                    if (typeof obj !== "object" || obj == null) {
+                        return false;
+                    }
+                    // Check that the keys and their values are correct
+                    const allowedKeys = new Set<string>(Object.values(CssSyntax).filter(v => v !== CssSyntax.OTHER));
+                    return Object.keys(obj).every(key => allowedKeys.has(key) && typeof (obj as any)[key] === "string");
+                },
+            },
+        },
+    );
+
+    if (!validOptions) {
+        return;
+    }
+
+    const disableFix = options?.disableFix ?? false;
+
+    const cssSyntax = getCssSyntax(root.source?.input.file || "");
+    if (cssSyntax === CssSyntax.OTHER) {
+        return;
+    }
+
+    let hasBpVariablesImport: boolean | undefined; // undefined means not checked yet
+    function assertBpVariablesImportExists(cssSyntaxType: CssSyntax.SASS | CssSyntax.LESS) {
+        const importPath = options?.variablesImportPath?.[cssSyntaxType] ?? BpVariableImportMap[cssSyntaxType];
+        if (hasBpVariablesImport == null) {
+            hasBpVariablesImport = checkImportExists(root, importPath);
+        }
+        if (!hasBpVariablesImport) {
+            insertImport(root, context, importPath);
+            hasBpVariablesImport = true;
+        }
+    }
+
+    root.walkRules(rule => {
+        parser(selectors => {
+            selectors.walkClasses(selector => {
+                for (const bannedPrefix of bannedPrefixes) {
+                    if (!selector.value.startsWith(`${bannedPrefix}-`)) {
+                        continue;
+                    }
+                    if ((context as any).fix && !disableFix) {
+                        assertBpVariablesImportExists(cssSyntax);
+                        rule.selector = rule.selector.replace(bannedPrefix, BpPrefixVariableMap[cssSyntax]);
+                    } else {
+                        stylelint.utils.report({
+                            // HACKHACK - offset by one because otherwise the error is reported at a wrong position
+                            index: selector.sourceIndex + 1,
+                            message: messages.expected(bannedPrefix, BpPrefixVariableMap[cssSyntax]),
+                            node: rule,
+                            result,
+                            ruleName,
+                        });
+                    }
+                }
+            });
+        }).processSync(rule.selector);
+    });
+}) as Plugin);
+
+enum CssSyntax {
+    SASS = "sass",
+    LESS = "less",
+    OTHER = "other",
+}
+
+const BpPrefixVariableMap: Record<Exclude<CssSyntax, CssSyntax.OTHER>, string> = {
+    [CssSyntax.SASS]: "#{$ns}",
+    [CssSyntax.LESS]: "@{ns}",
+};
+
+const BpVariableImportMap: Record<Exclude<CssSyntax, CssSyntax.OTHER>, string> = {
+    [CssSyntax.SASS]: "~@blueprntjs/core/lib/scss/variables",
+    [CssSyntax.LESS]: "~@blueprintjs/core/lib/less/variables",
+};
+
+/**
+ * Returns the flavor of the CSS we're dealing with.
+ */
+function getCssSyntax(fileName: string): CssSyntax {
+    if (fileName.endsWith(".scss")) {
+        return CssSyntax.SASS;
+    } else if (fileName.endsWith(".less")) {
+        return CssSyntax.LESS;
+    }
+    return CssSyntax.OTHER;
+}

packages/stylelint-plugin/src/tsconfig.json

@@ -0,0 +1,9 @@
+{
+    "extends": "../../../config/tsconfig.base",
+    "compilerOptions": {
+        "lib": ["es6", "dom"],
+        "module": "commonjs",
+        "outDir": "../lib",
+        "target": "ES2015"
+    }
+}

packages/stylelint-plugin/src/utils/checkImportExists.ts

@@ -0,0 +1,41 @@
+/* Copyright 2020 Palantir Technologies, Inc. All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.*/
+
+import type { Root } from "postcss";
+
+/**
+ * Returns true if the given import exists in the file, otherwise returns false.
+ */
+export function checkImportExists(root: Root, importPath: string): boolean {
+    let hasBpVarsImport = false;
+    root.walkAtRules(/^import$/i, atRule => {
+        // `atRule.params` includes quotes around the string, so we strip them.
+        if (stripQuotes(atRule.params) === importPath) {
+            hasBpVarsImport = true;
+            return false; // Stop the iteration
+        }
+        return true;
+    });
+    return hasBpVarsImport;
+}
+
+function stripQuotes(str: string): string {
+    if (
+        (str.charAt(0) === '"' && str.charAt(str.length - 1) === '"') ||
+        (str.charAt(0) === "'" && str.charAt(str.length - 1) === "'")
+    ) {
+        return str.substr(1, str.length - 2);
+    }
+    return str;
+}