fix(tslint): don't reread the input file on ts linting (close #2786) (#2787)

packages/@vue/cli-plugin-typescript/__tests__/tsPluginTSLint.spec.js

@@ -88,3 +88,28 @@ test('should ignore issues in node_modules', async () => {
   await run('vue-cli-service lint')
   expect(await read('node_modules/bad.ts')).toMatch(updatedMain)
 })
+
+test('should be able to fix mixed line endings', async () => {
+  const project = await create('ts-lint-mixed-line-endings', {
+    plugins: {
+      '@vue/cli-plugin-typescript': {
+        tsLint: true
+      }
+    }
+  })
+
+  const { write, run } = project
+
+  const b64 = 'PHRlbXBsYXRlPjwvdGVtcGxhdGU+DQoNCjxzY3JpcHQgbGFuZz0idHMiPg0KZXhwb3J0IGRlZmF1bHQgY2xhc3MgVGVzdCAgew0KICBnZXQgYXNzaWduZWUoKSB7DQogICAgdmFyIGl0ZW1zOnt0ZXh0OnN0cmluZzsgdmFsdWU6c3RyaW5nIHwgbnVtYmVyIHwgbnVsbH1bXSA9IFtdOw0KICAgIHJldHVybiBpdGVtczsNCiAgfQ0KDQp9DQo8L3NjcmlwdD4NCg0K'
+  const buf = Buffer.from(b64, 'base64')
+
+  await write('src/bad.vue', buf)
+
+  // Try twice to fix the file.
+  // For now, it will fail the first time, which corresponds to the behaviour of tslint.
+  try {
+    await run('vue-cli-service lint -- src/bad.vue')
+  } catch (e) { }
+
+  await run('vue-cli-service lint -- src/bad.vue')
+})

packages/@vue/cli-plugin-typescript/lib/tslint.js

@@ -29,6 +29,7 @@ module.exports = function lint (args = {}, api, silent) {
       if (isVueFile(file)) {
         const parts = vueFileCache.get(path.normalize(file))
         if (parts) {
+          parts.content = content;
           const { before, after } = parts
           content = `${before}\n${content.trim()}\n${after}`
         }
@@ -42,12 +43,19 @@ module.exports = function lint (args = {}, api, silent) {
   }
 
   const parseTSFromVueFile = file => {
+    
+    // If the file has already been cached, don't read the file again. Use the cache instead.
+    if (vueFileCache.has(file)) {
+      return vueFileCache.get(file).content;
+    }
+    
     const content = fs.readFileSync(file, 'utf-8')
     const { script } = vueCompiler.parseComponent(content, { pad: 'line' })
     if (script && /^tsx?$/.test(script.lang)) {
       vueFileCache.set(file, {
         before: content.slice(0, script.start),
-        after: content.slice(script.end)
+        after: content.slice(script.end),
+        content: script.content,
       })
       return script
     }