fix(reactivity-transform): don't overwrite scope and user imports

packages/reactivity-transform/__tests__/__snapshots__/reactivityTransform.spec.ts.snap

@@ -199,6 +199,27 @@ exports[`object destructure w/ mid-path default values 1`] = `
   "
 `;
 
+exports[`should not overwrite current scope 1`] = `
+"
+    const fn = () => {
+      const $ = () => 'foo'
+      const $ref = () => 'bar'
+      const $$ = () => 'baz'
+      console.log($())
+      console.log($ref())
+      console.log($$())
+    }
+    "
+`;
+
+exports[`should not overwrite importing 1`] = `
+"
+    import { $, $$ } from './foo'
+    $('foo')
+    $$('bar')
+    "
+`;
+
 exports[`should not rewrite scope variable 1`] = `
 "import { ref as _ref } from 'vue'
 

packages/reactivity-transform/__tests__/reactivityTransform.spec.ts

@@ -416,6 +416,35 @@ test('macro import alias and removal', () => {
   assertCode(code)
 })
 
+// #6838
+test('should not overwrite importing', () => {
+  const { code } = transform(
+    `
+    import { $, $$ } from './foo'
+    $('foo')
+    $$('bar')
+    `
+  )
+  assertCode(code)
+})
+
+// #6838
+test('should not overwrite current scope', () => {
+  const { code } = transform(
+    `
+    const fn = () => {
+      const $ = () => 'foo'
+      const $ref = () => 'bar'
+      const $$ = () => 'baz'
+      console.log($())
+      console.log($ref())
+      console.log($$())
+    }
+    `
+  )
+  assertCode(code)
+})
+
 describe('errors', () => {
   test('$ref w/ destructure', () => {
     expect(() => transform(`let { a } = $ref(1)`)).toThrow(

packages/reactivity-transform/src/reactivityTransform.ts

@@ -8,7 +8,11 @@ import {
   Program,
   VariableDeclarator,
   Expression,
-  VariableDeclaration
+  VariableDeclaration,
+  ImportDeclaration,
+  ImportSpecifier,
+  ImportDefaultSpecifier,
+  ImportNamespaceSpecifier
 } from '@babel/types'
 import MagicString, { SourceMap } from 'magic-string'
 import { walk } from 'estree-walker'
@@ -25,6 +29,7 @@ import { hasOwn, isArray, isString, genPropsAccessExp } from '@vue/shared'
 
 const CONVERT_SYMBOL = '$'
 const ESCAPE_SYMBOL = '$$'
+const IMPORT_SOURCE = 'vue/macros'
 const shorthands = ['ref', 'computed', 'shallowRef', 'toRef', 'customRef']
 const transformCheckRE = /[^\w]\$(?:\$|ref|computed|shallowRef)?\s*(\(|\<)/
 
@@ -48,6 +53,13 @@ export interface RefTransformResults {
   importedHelpers: string[]
 }
 
+export interface ImportBinding {
+  local: string
+  imported: string
+  source: string
+  specifier: ImportSpecifier | ImportDefaultSpecifier | ImportNamespaceSpecifier
+}
+
 export function transform(
   src: string,
   {
@@ -115,39 +127,40 @@ export function transformAST(
   // TODO remove when out of experimental
   warnExperimental()
 
-  let convertSymbol = CONVERT_SYMBOL
-  let escapeSymbol = ESCAPE_SYMBOL
+  const userImports: Record<string, ImportBinding> = Object.create(null)
+  for (const node of ast.body) {
+    if (node.type !== 'ImportDeclaration') continue
+    walkImportDeclaration(node)
+  }
 
   // macro import handling
-  for (const node of ast.body) {
-    if (
-      node.type === 'ImportDeclaration' &&
-      node.source.value === 'vue/macros'
-    ) {
-      // remove macro imports
-      s.remove(node.start! + offset, node.end! + offset)
-      // check aliasing
-      for (const specifier of node.specifiers) {
-        if (specifier.type === 'ImportSpecifier') {
-          const imported = (specifier.imported as Identifier).name
-          const local = specifier.local.name
-          if (local !== imported) {
-            if (imported === ESCAPE_SYMBOL) {
-              escapeSymbol = local
-            } else if (imported === CONVERT_SYMBOL) {
-              convertSymbol = local
-            } else {
-              error(
-                `macro imports for ref-creating methods do not support aliasing.`,
-                specifier
-              )
-            }
-          }
-        }
+  let convertSymbol: string | undefined
+  let escapeSymbol: string | undefined
+  for (const { local, imported, source, specifier } of Object.values(
+    userImports
+  )) {
+    if (source === IMPORT_SOURCE) {
+      if (imported === ESCAPE_SYMBOL) {
+        escapeSymbol = local
+      } else if (imported === CONVERT_SYMBOL) {
+        convertSymbol = local
+      } else if (imported !== local) {
+        error(
+          `macro imports for ref-creating methods do not support aliasing.`,
+          specifier
+        )
       }
     }
   }
 
+  // default symbol
+  if (!convertSymbol && !userImports[CONVERT_SYMBOL]) {
+    convertSymbol = CONVERT_SYMBOL
+  }
+  if (!escapeSymbol && !userImports[ESCAPE_SYMBOL]) {
+    escapeSymbol = ESCAPE_SYMBOL
+  }
+
   const importedHelpers = new Set<string>()
   const rootScope: Scope = {}
   const scopeStack: Scope[] = [rootScope]
@@ -170,7 +183,32 @@ export function transformAST(
     }
   }
 
+  function walkImportDeclaration(node: ImportDeclaration) {
+    const source = node.source.value
+    if (source === IMPORT_SOURCE) {
+      s.remove(node.start! + offset, node.end! + offset)
+    }
+
+    for (const specifier of node.specifiers) {
+      const local = specifier.local.name
+      const imported =
+        (specifier.type === 'ImportSpecifier' &&
+          specifier.imported.type === 'Identifier' &&
+          specifier.imported.name) ||
+        'default'
+      userImports[local] = {
+        source,
+        local,
+        imported,
+        specifier
+      }
+    }
+  }
+
   function isRefCreationCall(callee: string): string | false {
+    if (!convertSymbol || currentScope[convertSymbol] !== undefined) {
+      return false
+    }
     if (callee === convertSymbol) {
       return convertSymbol
     }
@@ -628,7 +666,11 @@ export function transformAST(
           )
         }
 
-        if (callee === escapeSymbol) {
+        if (
+          escapeSymbol &&
+          currentScope[escapeSymbol] === undefined &&
+          callee === escapeSymbol
+        ) {
           s.remove(node.callee.start! + offset, node.callee.end! + offset)
           escapeScope = node
         }