Add support for the updated import attributes proposal

Makefile.source.mjs

@@ -450,14 +450,16 @@ target["bootstrap-flow"] = function () {
 
 target["new-version-checklist"] = function () {
   // eslint-disable-next-line no-constant-condition
-  if (0) {
+  if (1) {
     console.log(
       `
 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
 !!!!!!                                                   !!!!!!
-!!!!!!         Write any message that should             !!!!!!
-!!!!!!            block the release here                 !!!!!!
+!!!!!!              Update the version in                !!!!!!
+!!!!!! packages/babel-plugin-syntax-import-attributes/src/index.ts
+!!!!!!                    and                            !!!!!!
+!!!!!! /Users/nic/Documents/dev/babel/babel/packages/babel-preset-env/src/available-plugins.ts#L159
 !!!!!!                                                   !!!!!!
 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

babel.config.js

@@ -236,6 +236,14 @@ module.exports = function (api) {
             "flag-IS_STANDALONE",
           ],
 
+          [
+            pluginToggleBooleanFlag,
+            {
+              name: "process.env.IS_PUBLISH",
+              value: bool(process.env.IS_PUBLISH),
+            },
+          ],
+
           process.env.STRIP_BABEL_8_FLAG && [
             pluginToggleBooleanFlag,
             {

packages/babel-core/src/parser/util/missing-plugin-helper.ts

@@ -84,10 +84,10 @@ const pluginNameMap: Record<
       url: "https://github.com/babel/babel/tree/main/packages/babel-preset-react",
     },
   },
-  importAssertions: {
+  importAttributes: {
     syntax: {
-      name: "@babel/plugin-syntax-import-assertions",
-      url: "https://github.com/babel/babel/tree/main/packages/babel-plugin-syntax-import-assertions",
+      name: "@babel/plugin-syntax-import-attributes",
+      url: "https://github.com/babel/babel/tree/main/packages/babel-plugin-syntax-import-attributes",
     },
   },
   pipelineOperator: {
@@ -207,6 +207,13 @@ if (!process.env.BABEL_8_BREAKING) {
         url: "https://github.com/babel/babel/tree/main/packages/babel-plugin-proposal-export-namespace-from",
       },
     },
+    // Will be removed
+    importAssertions: {
+      syntax: {
+        name: "@babel/plugin-syntax-import-assertions",
+        url: "https://github.com/babel/babel/tree/main/packages/babel-plugin-syntax-import-assertions",
+      },
+    },
     importMeta: {
       syntax: {
         name: "@babel/plugin-syntax-import-meta",

packages/babel-generator/src/generators/modules.ts

@@ -66,15 +66,48 @@ export function ExportNamespaceSpecifier(
   this.print(node.exported, node);
 }
 
-export function _printAssertions(
+let warningShown = false;
+
+export function _printAttributes(
   this: Printer,
-  node: Extract<t.Node, { assertions?: t.ImportAttribute[] }>,
+  node: Extract<t.Node, { attributes?: t.ImportAttribute[] }>,
 ) {
-  this.word("assert");
+  const { importAttributesKeyword } = this.format;
+  const { attributes, assertions } = node;
+
+  if (
+    attributes &&
+    !importAttributesKeyword &&
+    // In the production build only show the warning once.
+    // We want to show it per-usage locally for tests.
+    (!process.env.IS_PUBLISH || !warningShown)
+  ) {
+    warningShown = true;
+    console.warn(`\
+You are using import attributes, without specifying the desired output syntax.
+Please specify the "importAttributesKeyword" generator option, whose value can be one of:
+ - "with"        : \`import { a } from "b" with { type: "json" };\`
+ - "assert"      : \`import { a } from "b" assert { type: "json" };\`
+ - "with-legacy" : \`import { a } from "b" with type: "json";\`
+`);
+  }
+
+  const useAssertKeyword =
+    importAttributesKeyword === "assert" ||
+    (!importAttributesKeyword && assertions);
+
+  this.word(useAssertKeyword ? "assert" : "with");
   this.space();
+
+  if (!useAssertKeyword && importAttributesKeyword !== "with") {
+    // with-legacy
+    this.printList(attributes || assertions, node);
+    return;
+  }
+
   this.token("{");
   this.space();
-  this.printList(node.assertions, node);
+  this.printList(attributes || assertions, node);
   this.space();
   this.token("}");
 }
@@ -93,12 +126,12 @@ export function ExportAllDeclaration(
   this.space();
   this.word("from");
   this.space();
-  // @ts-expect-error Fixme: assertions is not defined in DeclareExportAllDeclaration
-  if (node.assertions?.length) {
+  // @ts-expect-error Fixme: attributes is not defined in DeclareExportAllDeclaration
+  if (node.attributes?.length || node.assertions?.length) {
     this.print(node.source, node, true);
     this.space();
-    // @ts-expect-error Fixme: assertions is not defined in DeclareExportAllDeclaration
-    this._printAssertions(node);
+    // @ts-expect-error Fixme: attributes is not defined in DeclareExportAllDeclaration
+    this._printAttributes(node);
   } else {
     this.print(node.source, node);
   }
@@ -173,10 +206,10 @@ export function ExportNamedDeclaration(
       this.space();
       this.word("from");
       this.space();
-      if (node.assertions?.length) {
+      if (node.attributes?.length || node.assertions?.length) {
         this.print(node.source, node, true);
         this.space();
-        this._printAssertions(node);
+        this._printAttributes(node);
       } else {
         this.print(node.source, node);
       }
@@ -251,23 +284,13 @@ export function ImportDeclaration(this: Printer, node: t.ImportDeclaration) {
     this.space();
   }
 
-  if (node.assertions?.length) {
+  if (node.attributes?.length || node.assertions?.length) {
     this.print(node.source, node, true);
     this.space();
-    this._printAssertions(node);
+    this._printAttributes(node);
   } else {
     this.print(node.source, node);
   }
-  if (!process.env.BABEL_8_BREAKING) {
-    // @ts-ignore(Babel 7 vs Babel 8) Babel 7 supports module attributes
-    if (node.attributes?.length) {
-      this.space();
-      this.word("with");
-      this.space();
-      // @ts-ignore(Babel 7 vs Babel 8) Babel 7 supports module attributes
-      this.printList(node.attributes, node);
-    }
-  }
 
   this.semicolon();
 }

packages/babel-generator/src/index.ts

@@ -73,6 +73,7 @@ function normalizeOptions(
     },
     recordAndTupleSyntaxType: opts.recordAndTupleSyntaxType,
     topicToken: opts.topicToken,
+    importAttributesKeyword: opts.importAttributesKeyword,
   };
 
   if (!process.env.BABEL_8_BREAKING) {
@@ -218,11 +219,20 @@ export interface GeneratorOptions {
    * For use with the recordAndTuple token.
    */
   recordAndTupleSyntaxType?: RecordAndTuplePluginOptions["syntaxType"];
+
   /**
    * For use with the Hack-style pipe operator.
    * Changes what token is used for pipe bodies’ topic references.
    */
   topicToken?: PipelineOperatorPluginOptions["topicToken"];
+
+  /**
+   * The import attributes syntax style:
+   * - "with"        : `import { a } from "b" with { type: "json" };`
+   * - "assert"      : `import { a } from "b" assert { type: "json" };`
+   * - "with-legacy" : `import { a } from "b" with type: "json";`
+   */
+  importAttributesKeyword?: "with" | "assert" | "with-legacy";
 }
 
 export interface GeneratorResult {

packages/babel-generator/src/printer.ts

@@ -18,7 +18,7 @@ import type { Opts as jsescOptions } from "jsesc";
 import * as generatorFunctions from "./generators";
 import type SourceMap from "./source-map";
 import * as charCodes from "charcodes";
-import { type TraceMap } from "@jridgewell/trace-mapping";
+import type { TraceMap } from "@jridgewell/trace-mapping";
 
 const SCIENTIFIC_NOTATION = /e/i;
 const ZERO_DECIMAL_INTEGER = /\.0+$/;
@@ -77,6 +77,15 @@ export type Format = {
    * @deprecated Removed in Babel 8
    */
   decoratorsBeforeExport?: boolean;
+  /**
+   * The import attributes syntax style:
+   * - "with"        : `import { a } from "b" with { type: "json" };`
+   * - "assert"      : `import { a } from "b" assert { type: "json" };`
+   * - "with-legacy" : `import { a } from "b" with type: "json";`
+   * - "auto-legacy" : "assert" if the AST node has an .assertions property,
+   *                   "with-legacy" if it has an .attributes property.
+   */
+  importAttributesKeyword?: "with" | "assert" | "with-legacy";
 };
 
 interface AddNewlinesOptions {

packages/babel-generator/test/fixtures/importAttributesKeyword/assertions-assert-to-assert/input.js

@@ -0,0 +1 @@
+import "a" assert { type: "json" };

packages/babel-generator/test/fixtures/importAttributesKeyword/assertions-assert-to-assert/options.json

@@ -0,0 +1,4 @@
+{
+  "plugins": ["importAssertions"],
+  "importAttributesKeyword": "assert"
+}

packages/babel-generator/test/fixtures/importAttributesKeyword/assertions-assert-to-assert/output.js

@@ -0,0 +1 @@
+import "a" assert { type: "json" };

packages/babel-generator/test/fixtures/importAttributesKeyword/assertions-assert-to-default/input.js

@@ -0,0 +1 @@
+import "a" assert { type: "json" };

packages/babel-generator/test/fixtures/importAttributesKeyword/assertions-assert-to-default/options.json

@@ -0,0 +1,3 @@
+{
+  "plugins": ["importAssertions"]
+}

packages/babel-generator/test/fixtures/importAttributesKeyword/assertions-assert-to-default/output.js

@@ -0,0 +1 @@
+import "a" assert { type: "json" };

packages/babel-generator/test/fixtures/importAttributesKeyword/assertions-assert-to-with-legacy/input.js

@@ -0,0 +1 @@
+import "a" with { type: "json" };

packages/babel-generator/test/fixtures/importAttributesKeyword/assertions-assert-to-with-legacy/options.json

@@ -0,0 +1,5 @@
+{
+  "plugins": ["importAssertions"],
+  "importAttributesKeyword": "with-legacy",
+  "expectedReParseError": true
+}

packages/babel-generator/test/fixtures/importAttributesKeyword/assertions-assert-to-with-legacy/output.js

@@ -0,0 +1 @@
+import "a" with type: "json";

packages/babel-generator/test/fixtures/importAttributesKeyword/assertions-assert-to-with/input.js

@@ -0,0 +1 @@
+import "a" assert { type: "json" };

packages/babel-generator/test/fixtures/importAttributesKeyword/assertions-assert-to-with/options.json

@@ -0,0 +1,4 @@
+{
+  "plugins": ["importAssertions"],
+  "importAttributesKeyword": "with"
+}

packages/babel-generator/test/fixtures/importAttributesKeyword/assertions-assert-to-with/output.js

@@ -0,0 +1 @@
+import "a" with { type: "json" };

packages/babel-generator/test/fixtures/importAttributesKeyword/assertions-with-to-assert/input.js

@@ -0,0 +1 @@
+import "a" with { type: "json" };

packages/babel-generator/test/fixtures/importAttributesKeyword/assertions-with-to-assert/options.json

@@ -0,0 +1,4 @@
+{
+  "plugins": ["importAssertions"],
+  "importAttributesKeyword": "assert"
+}

packages/babel-generator/test/fixtures/importAttributesKeyword/assertions-with-to-assert/output.js

@@ -0,0 +1 @@
+import "a" assert { type: "json" };

packages/babel-generator/test/fixtures/importAttributesKeyword/assertions-with-to-default/input.js

@@ -0,0 +1 @@
+import "a" with { type: "json" };

packages/babel-generator/test/fixtures/importAttributesKeyword/assertions-with-to-default/options.json

@@ -0,0 +1,5 @@
+{
+  "plugins": ["importAssertions"],
+  "warns": "You are using import attributes, without specifying the desired output syntax.",
+  "expectedReParseError": true
+}

packages/babel-generator/test/fixtures/importAttributesKeyword/assertions-with-to-default/output.js

@@ -0,0 +1 @@
+import "a" with type: "json";

packages/babel-generator/test/fixtures/importAttributesKeyword/assertions-with-to-with-legacy/input.js

@@ -0,0 +1 @@
+import "a" with { type: "json" };

packages/babel-generator/test/fixtures/importAttributesKeyword/assertions-with-to-with-legacy/options.json

@@ -0,0 +1,5 @@
+{
+  "plugins": ["importAssertions"],
+  "importAttributesKeyword": "with-legacy",
+  "expectedReParseError": true
+}

packages/babel-generator/test/fixtures/importAttributesKeyword/assertions-with-to-with-legacy/output.js

@@ -0,0 +1 @@
+import "a" with type: "json";

packages/babel-generator/test/fixtures/importAttributesKeyword/assertions-with-to-with/input.js

@@ -0,0 +1 @@
+import "a" with { type: "json" };

packages/babel-generator/test/fixtures/importAttributesKeyword/assertions-with-to-with/options.json

@@ -0,0 +1,4 @@
+{
+  "plugins": ["importAssertions"],
+  "importAttributesKeyword": "with"
+}

packages/babel-generator/test/fixtures/importAttributesKeyword/assertions-with-to-with/output.js

@@ -0,0 +1 @@
+import "a" with { type: "json" };

packages/babel-generator/test/fixtures/importAttributesKeyword/attributes-assert-to-assert/input.js

@@ -0,0 +1 @@
+import "a" assert { type: "json" };

packages/babel-generator/test/fixtures/importAttributesKeyword/attributes-assert-to-assert/options.json

@@ -0,0 +1,4 @@
+{
+  "plugins": [["importAttributes", { "deprecatedAssertSyntax": true }]],
+  "importAttributesKeyword": "assert"
+}

packages/babel-generator/test/fixtures/importAttributesKeyword/attributes-assert-to-assert/output.js

@@ -0,0 +1 @@
+import "a" assert { type: "json" };

packages/babel-generator/test/fixtures/importAttributesKeyword/attributes-assert-to-default/input.js

@@ -0,0 +1 @@
+import "a" assert { type: "json" };

packages/babel-generator/test/fixtures/importAttributesKeyword/attributes-assert-to-default/options.json

@@ -0,0 +1,5 @@
+{
+  "plugins": [["importAttributes", { "deprecatedAssertSyntax": true }]],
+  "warns": "You are using import attributes, without specifying the desired output syntax.",
+  "expectedReParseError": true
+}

packages/babel-generator/test/fixtures/importAttributesKeyword/attributes-assert-to-default/output.js

@@ -0,0 +1 @@
+import "a" with type: "json";

packages/babel-generator/test/fixtures/importAttributesKeyword/attributes-assert-to-with-legacy/input.js

@@ -0,0 +1 @@
+import "a" with { type: "json" };

packages/babel-generator/test/fixtures/importAttributesKeyword/attributes-assert-to-with-legacy/options.json

@@ -0,0 +1,5 @@
+{
+  "plugins": [["importAttributes", { "deprecatedAssertSyntax": true }]],
+  "importAttributesKeyword": "with-legacy",
+  "expectedReParseError": true
+}

packages/babel-generator/test/fixtures/importAttributesKeyword/attributes-assert-to-with-legacy/output.js

@@ -0,0 +1 @@
+import "a" with type: "json";

packages/babel-generator/test/fixtures/importAttributesKeyword/attributes-assert-to-with/input.js

@@ -0,0 +1 @@
+import "a" assert { type: "json" };

packages/babel-generator/test/fixtures/importAttributesKeyword/attributes-assert-to-with/options.json

@@ -0,0 +1,4 @@
+{
+  "plugins": [["importAttributes", { "deprecatedAssertSyntax": true }]],
+  "importAttributesKeyword": "with"
+}

packages/babel-generator/test/fixtures/importAttributesKeyword/attributes-assert-to-with/output.js

@@ -0,0 +1 @@
+import "a" with { type: "json" };

packages/babel-generator/test/fixtures/importAttributesKeyword/attributes-with-to-assert/input.js

@@ -0,0 +1 @@
+import "a" with { type: "json" };

packages/babel-generator/test/fixtures/importAttributesKeyword/attributes-with-to-assert/options.json

@@ -0,0 +1,5 @@
+{
+  "plugins": ["importAttributes"],
+  "importAttributesKeyword": "assert",
+  "expectedReParseError": true
+}

packages/babel-generator/test/fixtures/importAttributesKeyword/attributes-with-to-assert/output.js

@@ -0,0 +1 @@
+import "a" assert { type: "json" };

packages/babel-generator/test/fixtures/importAttributesKeyword/attributes-with-to-default/input.js

@@ -0,0 +1 @@
+import "a" with { type: "json" };

packages/babel-generator/test/fixtures/importAttributesKeyword/attributes-with-to-default/options.json

@@ -0,0 +1,5 @@
+{
+  "plugins": ["importAttributes"],
+  "warns": "You are using import attributes, without specifying the desired output syntax.",
+  "expectedReParseError": true
+}

packages/babel-generator/test/fixtures/importAttributesKeyword/attributes-with-to-default/output.js

@@ -0,0 +1 @@
+import "a" with type: "json";

packages/babel-generator/test/fixtures/importAttributesKeyword/attributes-with-to-with-legacy/input.js

@@ -0,0 +1 @@
+import "a" with { type: "json" };

packages/babel-generator/test/fixtures/importAttributesKeyword/attributes-with-to-with-legacy/options.json

@@ -0,0 +1,5 @@
+{
+  "plugins": ["importAttributes"],
+  "importAttributesKeyword": "with-legacy",
+  "expectedReParseError": true
+}

packages/babel-generator/test/fixtures/importAttributesKeyword/attributes-with-to-with-legacy/output.js

@@ -0,0 +1 @@
+import "a" with type: "json";

packages/babel-generator/test/fixtures/importAttributesKeyword/attributes-with-to-with/input.js

@@ -0,0 +1 @@
+import "a" with { type: "json" };

packages/babel-generator/test/fixtures/importAttributesKeyword/attributes-with-to-with/options.json

@@ -0,0 +1,4 @@
+{
+  "plugins": ["importAttributes"],
+  "importAttributesKeyword": "with"
+}

packages/babel-generator/test/fixtures/importAttributesKeyword/attributes-with-to-with/output.js

@@ -0,0 +1 @@
+import "a" with { type: "json" };

packages/babel-generator/test/fixtures/importAttributesKeyword/legacy-module-attributes-to-assert/input.js

@@ -0,0 +1 @@
+import "a" with type: "json";