⭐️New: Add vue/no-deprecated-slot-attribute rule (#839)

* ⭐️New: Add vue/no-deprecated-slot-attribute rule

* Made the following changes

- Changed to check `v-bind:slot`.
- Changed not to autofix, if it becomes an invalid attribute name after autofix.

* Changed not to autofix if `v-bind:slot` contains non Latin characters.

* Changed it to autofix only when `slot` is attached to `<template>`

Co-authored-by: Toru Nagashima <public@mysticatea.dev>

docs/rules/README.md

@@ -153,6 +153,7 @@ For example:
 | [vue/keyword-spacing](./keyword-spacing.md) | enforce consistent spacing before and after keywords | :wrench: |
 | [vue/match-component-file-name](./match-component-file-name.md) | require component name property to match its file name |  |
 | [vue/no-boolean-default](./no-boolean-default.md) | disallow boolean defaults | :wrench: |
+| [vue/no-deprecated-slot-attribute](./no-deprecated-slot-attribute.md) | disallow deprecated `slot` attribute (in Vue.js 2.6.0+) | :wrench: |
 | [vue/no-deprecated-scope-attribute](./no-deprecated-scope-attribute.md) | disallow deprecated `scope` attribute (in Vue.js 2.5.0+) | :wrench: |
 | [vue/no-empty-pattern](./no-empty-pattern.md) | disallow empty destructuring patterns |  |
 | [vue/no-reserved-component-names](./no-reserved-component-names.md) | disallow the use of reserved names in component definitions |  |

docs/rules/no-deprecated-slot-attribute.md

@@ -0,0 +1,44 @@
+---
+pageClass: rule-details
+sidebarDepth: 0
+title: vue/no-deprecated-slot-attribute
+description: disallow deprecated `slot` attribute (in Vue.js 2.6.0+)
+---
+# vue/no-deprecated-slot-attribute
+> disallow deprecated `slot` attribute (in Vue.js 2.6.0+)
+
+- :wrench: The `--fix` option on the [command line](https://eslint.org/docs/user-guide/command-line-interface#fixing-problems) can automatically fix some of the problems reported by this rule.
+
+## :book: Rule Details
+
+This rule reports deprecated `slot` attribute in Vue.js v2.6.0+.
+
+<eslint-code-block fix :rules="{'vue/no-deprecated-slot-attribute': ['error']}">
+
+```vue
+<template>
+  <ListComponent>
+    <!-- ✓ GOOD -->
+    <template v-slot:name>
+      {{ props.title }}
+    </template>
+  </ListComponent>
+  <ListComponent>
+    <!-- ✗ BAD -->
+    <template slot="name">
+      {{ props.title }}
+    </template>
+  </ListComponent>
+</template>
+```
+
+</eslint-code-block>
+
+## :books: Further reading
+
+- [API - slot](https://vuejs.org/v2/api/#slot-deprecated)
+
+## :mag: Implementation
+
+- [Rule source](https://github.com/vuejs/eslint-plugin-vue/blob/master/lib/rules/no-deprecated-slot-attribute.js)
+- [Test source](https://github.com/vuejs/eslint-plugin-vue/blob/master/tests/lib/rules/no-deprecated-slot-attribute.js)

lib/index.js

@@ -37,6 +37,7 @@ module.exports = {
     'no-async-in-computed-properties': require('./rules/no-async-in-computed-properties'),
     'no-boolean-default': require('./rules/no-boolean-default'),
     'no-confusing-v-for-v-if': require('./rules/no-confusing-v-for-v-if'),
+    'no-deprecated-slot-attribute': require('./rules/no-deprecated-slot-attribute'),
     'no-deprecated-scope-attribute': require('./rules/no-deprecated-scope-attribute'),
     'no-dupe-keys': require('./rules/no-dupe-keys'),
     'no-duplicate-attributes': require('./rules/no-duplicate-attributes'),

lib/rules/no-deprecated-slot-attribute.js

@@ -0,0 +1,28 @@
+/**
+ * @author Yosuke Ota
+ * See LICENSE file in root directory for full license.
+ */
+'use strict'
+
+const utils = require('../utils')
+const slotAttribute = require('./syntaxes/slot-attribute')
+
+module.exports = {
+  meta: {
+    type: 'suggestion',
+    docs: {
+      description: 'disallow deprecated `slot` attribute (in Vue.js 2.6.0+)',
+      category: undefined,
+      url: 'https://eslint.vuejs.org/rules/no-deprecated-slot-attribute.html'
+    },
+    fixable: 'code',
+    schema: [],
+    messages: {
+      forbiddenSlotAttribute: '`slot` attributes are deprecated.'
+    }
+  },
+  create (context) {
+    const templateBodyVisitor = slotAttribute.createTemplateBodyVisitor(context)
+    return utils.defineTemplateBodyVisitor(context, templateBodyVisitor)
+  }
+}

lib/rules/syntaxes/slot-attribute.js

@@ -0,0 +1,128 @@
+/**
+ * @author Yosuke Ota
+ * See LICENSE file in root directory for full license.
+ */
+'use strict'
+module.exports = {
+  deprecated: '2.6.0',
+  createTemplateBodyVisitor (context) {
+    const sourceCode = context.getSourceCode()
+
+    /**
+     * Checks whether the given node can convert to the `v-slot`.
+     * @param {VAttribute} slotAttr node of `slot`
+     * @returns {boolean} `true` if the given node can convert to the `v-slot`
+     */
+    function canConvertFromSlotToVSlot (slotAttr) {
+      if (slotAttr.parent.parent.name !== 'template') {
+        return false
+      }
+      if (!slotAttr.value) {
+        return true
+      }
+      const slotName = slotAttr.value.value
+      // If non-Latin characters are included it can not be converted.
+      return !/[^a-z]/i.test(slotName)
+    }
+
+    /**
+     * Checks whether the given node can convert to the `v-slot`.
+     * @param {VAttribute} slotAttr node of `v-bind:slot`
+     * @returns {boolean} `true` if the given node can convert to the `v-slot`
+     */
+    function canConvertFromVBindSlotToVSlot (slotAttr) {
+      if (slotAttr.parent.parent.name !== 'template') {
+        return false
+      }
+
+      if (!slotAttr.value) {
+        return true
+      }
+
+      if (!slotAttr.value.expression) {
+        // parse error or empty expression
+        return false
+      }
+      const slotName = sourceCode.getText(slotAttr.value.expression).trim()
+      // If non-Latin characters are included it can not be converted.
+      // It does not check the space only because `a>b?c:d` should be rejected.
+      return !/[^a-z]/i.test(slotName)
+    }
+
+    /**
+     * Convert to `v-slot`.
+     * @param {object} fixer fixer
+     * @param {VAttribute} slotAttr node of `slot`
+     * @param {string | null} slotName name of `slot`
+     * @param {boolean} vBind `true` if `slotAttr` is `v-bind:slot`
+     * @returns {*} fix data
+     */
+    function fixSlotToVSlot (fixer, slotAttr, slotName, vBind) {
+      const element = slotAttr.parent
+      const scopeAttr = element.attributes
+        .find(attr => attr.directive === true && attr.key.name && (
+          attr.key.name.name === 'slot-scope' ||
+          attr.key.name.name === 'scope'
+        ))
+      const nameArgument = slotName ? (vBind ? `:[${slotName}]` : `:${slotName}`) : ''
+      const scopeValue = scopeAttr && scopeAttr.value
+        ? `=${sourceCode.getText(scopeAttr.value)}`
+        : ''
+
+      const replaceText = `v-slot${nameArgument}${scopeValue}`
+      const fixers = [
+        fixer.replaceText(slotAttr || scopeAttr, replaceText)
+      ]
+      if (slotAttr && scopeAttr) {
+        fixers.push(fixer.remove(scopeAttr))
+      }
+      return fixers
+    }
+    /**
+     * Reports `slot` node
+     * @param {VAttribute} slotAttr node of `slot`
+     * @returns {void}
+     */
+    function reportSlot (slotAttr) {
+      context.report({
+        node: slotAttr.key,
+        messageId: 'forbiddenSlotAttribute',
+        // fix to use `v-slot`
+        fix (fixer) {
+          if (!canConvertFromSlotToVSlot(slotAttr)) {
+            return null
+          }
+          const slotName = slotAttr.value &&
+            slotAttr.value.value
+          return fixSlotToVSlot(fixer, slotAttr, slotName, false)
+        }
+      })
+    }
+    /**
+     * Reports `v-bind:slot` node
+     * @param {VAttribute} slotAttr node of `v-bind:slot`
+     * @returns {void}
+     */
+    function reportVBindSlot (slotAttr) {
+      context.report({
+        node: slotAttr.key,
+        messageId: 'forbiddenSlotAttribute',
+        // fix to use `v-slot`
+        fix (fixer) {
+          if (!canConvertFromVBindSlotToVSlot(slotAttr)) {
+            return null
+          }
+          const slotName = slotAttr.value &&
+            slotAttr.value.expression &&
+            sourceCode.getText(slotAttr.value.expression).trim()
+          return fixSlotToVSlot(fixer, slotAttr, slotName, true)
+        }
+      })
+    }
+
+    return {
+      "VAttribute[directive=false][key.name='slot']": reportSlot,
+      "VAttribute[directive=true][key.name.name='bind'][key.argument.name='slot']": reportVBindSlot
+    }
+  }
+}