Support autofix in gts files

lib/preprocessors/glimmer.js

@@ -128,6 +128,7 @@ function mapRange(messages, filename) {
     return flattened;
   }
 
+  const originalDoc = new DocumentLines(original);
   const transformedDoc = new DocumentLines(transformed);
 
   const lines = transformed.split('\n');
@@ -193,6 +194,19 @@ function mapRange(messages, filename) {
   });
 
   return filtered.map((message) => {
+    // we need to adjust the fix range provided by eslint to the correct range in the original content
+    // the lines & columns did not change, except for the template part. but the total offset did, as the template content changed
+    // therefore we need to remap the range correctly:
+    // 1. convert range in transformed content to line & column. We know this is the same, but offsets are different
+    // 2. convert line & column back to offsets in the original content
+    if (message.fix) {
+      const [start, end] = message.fix.range;
+      const startPos = transformedDoc.offsetToPosition(start);
+      const endPos = transformedDoc.offsetToPosition(end);
+      const fix = message.fix;
+      fix.range = [originalDoc.positionToOffset(startPos), originalDoc.positionToOffset(endPos)];
+    }
+
     // 1. handle eslint diagnostics on single lines.
     if (message.line === message.endLine) {
       const originalLine = originalLines[message.line - 1];
@@ -295,4 +309,5 @@ function mapRange(messages, filename) {
 module.exports = {
   preprocess: gjs,
   postprocess: mapRange,
+  supportsAutofix: true,
 };

lib/utils/document.js

@@ -1,5 +1,3 @@
-/* istanbul ignore file */
-
 /**
  * @typedef {{ line: number; character: number }} Position
  */
@@ -75,6 +73,7 @@ function computeLineStarts(text) {
   return result;
 }
 
+/* istanbul ignore next */
 /**
  * @param {number} ch
  * @return {boolean}

tests/lib/rules-preprocessor/gjs-gts-processor-test.js

@@ -35,6 +35,7 @@ function initESLint(options) {
       plugins: ['ember'],
       extends: ['plugin:ember/recommended'],
       rules: {
+        quotes: ['error', 'single'],
         semi: ['error', 'always'],
         'object-curly-spacing': ['error', 'always'],
         'lines-between-class-members': 'error',
@@ -173,7 +174,7 @@ const invalid = [
       import Component from '@glimmer/component';
 
       export default class MyComponent extends Component {
-        foo = "bar";
+        foo = 'bar';
         <template>"hi"</template>
       }
     `,
@@ -193,7 +194,7 @@ const invalid = [
       import Component from '@glimmer/component';
 
       export default class MyComponent extends Component {
-        foo = "bar";
+        foo = 'bar';
         <template>"hi"
         </template>
       }
@@ -208,6 +209,36 @@ const invalid = [
       },
     ],
   },
+  {
+    filename: 'my-component.gjs',
+    code: `
+      import Component from "@glimmer/component";
+      export default class MyComponent extends Component {
+        foo = 'bar';
+        <template>"hi"
+        </template>
+      }
+    `,
+    errors: [
+      {
+        message: 'Strings must use singlequote.',
+        line: 2,
+        endLine: 2,
+        endColumn: 49,
+        column: 29,
+        fix: {
+          range: [29, 49],
+        },
+      },
+      {
+        message: 'Expected blank line between class members.',
+        line: 5,
+        endLine: 6,
+        column: 9,
+        endColumn: 20,
+      },
+    ],
+  },
 ];
 
 describe('template-vars', () => {