[Babel 8]: remove module attributes parser/generator support (#13308)

* breaking: remove support of moduleAttributes

* Update packages/babel-parser/src/plugin-utils.js

Co-authored-by: Nicolò Ribaudo <nicolo.ribaudo@gmail.com>

* chore: remove todo comments

* make prettier happy

Co-authored-by: Nicolò Ribaudo <nicolo.ribaudo@gmail.com>

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

@@ -204,15 +204,15 @@ export function ImportDeclaration(this: Printer, node: t.ImportDeclaration) {
   this.print(node.source, node);
 
   this.printAssertions(node);
-  // todo(Babel 8): remove this if branch
+  if (!process.env.BABEL_8_BREAKING) {
-  // `module-attributes` support is discontinued, use `import-assertions` instead.
-  // @ts-expect-error
-  if (node.attributes?.length) {
-    this.space();
-    this.word("with");
-    this.space();
     // @ts-expect-error
-    this.printList(node.attributes, node);
+    if (node.attributes?.length) {
+      this.space();
+      this.word("with");
+      this.space();
+      // @ts-expect-error
+      this.printList(node.attributes, node);
+    }
   }
 
   this.semicolon();

packages/babel-generator/test/fixtures/types/ModuleAttributes/options.json

@@ -7,5 +7,6 @@
       }
     ]
   ],
-  "sourceType": "module"
+  "sourceType": "module",
+  "BABEL_8_BREAKING": false
 }

packages/babel-parser/src/parser/expression.js

@@ -857,10 +857,12 @@ export default class ExpressionParser extends LValParser {
   ): N.Expression {
     if (node.callee.type === "Import") {
       if (node.arguments.length === 2) {
-        // todo(Babel 8): remove the if condition,
+        if (process.env.BABEL_8_BREAKING) {
-        // moduleAttributes is renamed to importAssertions
-        if (!this.hasPlugin("moduleAttributes")) {
           this.expectPlugin("importAssertions");
+        } else {
+          if (!this.hasPlugin("moduleAttributes")) {
+            this.expectPlugin("importAssertions");
+          }
         }
       }
       if (node.arguments.length === 0 || node.arguments.length > 2) {

packages/babel-parser/src/parser/statement.js

@@ -2197,9 +2197,7 @@ export default class StatementParser extends ExpressionParser {
     const assertions = this.maybeParseImportAssertions();
     if (assertions) {
       node.assertions = assertions;
-    }
+    } else if (!process.env.BABEL_8_BREAKING) {
-    // todo(Babel 8): remove module attributes support
-    else {
       const attributes = this.maybeParseModuleAttributes();
       if (attributes) {
         node.attributes = attributes;

packages/babel-parser/src/plugin-utils.js

@@ -87,22 +87,28 @@ export function validatePlugins(plugins: PluginList) {
   }
 
   if (hasPlugin(plugins, "moduleAttributes")) {
-    if (hasPlugin(plugins, "importAssertions")) {
+    if (process.env.BABEL_8_BREAKING) {
       throw new Error(
-        "Cannot combine importAssertions and moduleAttributes plugins.",
+        "`moduleAttributes` has been removed in Babel 8, please use `importAssertions` parser plugin, or `@babel/plugin-syntax-import-assertions`.",
       );
-    }
+    } else {
-    const moduleAttributesVerionPluginOption = getPluginOption(
+      if (hasPlugin(plugins, "importAssertions")) {
-      plugins,
+        throw new Error(
-      "moduleAttributes",
+          "Cannot combine importAssertions and moduleAttributes plugins.",
-      "version",
+        );
-    );
+      }
-    if (moduleAttributesVerionPluginOption !== "may-2020") {
+      const moduleAttributesVerionPluginOption = getPluginOption(
-      throw new Error(
+        plugins,
-        "The 'moduleAttributes' plugin requires a 'version' option," +
+        "moduleAttributes",
-          " representing the last proposal update. Currently, the" +
+        "version",
-          " only supported value is 'may-2020'.",
       );
+      if (moduleAttributesVerionPluginOption !== "may-2020") {
+        throw new Error(
+          "The 'moduleAttributes' plugin requires a 'version' option," +
+            " representing the last proposal update. Currently, the" +
+            " only supported value is 'may-2020'.",
+        );
+      }
     }
   }
 

packages/babel-parser/test/fixtures/experimental/_no-plugin/module-attributes/options.json

@@ -1,3 +1,4 @@
 {
-  "throws": "This experimental syntax requires enabling the parser plugin: 'moduleAttributes' (1:27)"
+  "throws": "This experimental syntax requires enabling the parser plugin: 'moduleAttributes' (1:27)",
+  "BABEL_8_BREAKING": false
 }

packages/babel-parser/test/fixtures/experimental/module-attributes/options.json

@@ -0,0 +1,3 @@
+{
+  "BABEL_8_BREAKING": false
+}

packages/babel-parser/test/plugin-options.js

@@ -65,4 +65,13 @@ describe("plugin options", function () {
       expect(getParser(SYNTAX_2, [OPT_1, OPT_2])).toThrow();
     });
   });
+  describe("'moduleAttributes' plugin", () => {
+    (process.env.BABEL_8_BREAKING ? it : it.skip)("removed in Babel 8", () => {
+      expect(
+        getParser("", ["moduleAttributes"]),
+      ).toThrowErrorMatchingInlineSnapshot(
+        `"\`moduleAttributes\` has been removed in Babel 8, please use \`importAssertions\` parser plugin, or \`@babel/plugin-syntax-import-assertions\`."`,
+      );
+    });
+  });
 });