do not decode text inside script/style tags (fix #5526)

src/compiler/parser/html-parser.js

@@ -46,7 +46,7 @@ let IS_REGEX_CAPTURING_BROKEN = false
 })
 
 // Special Elements (can contain anything)
-const isPlainTextElement = makeMap('script,style,textarea', true)
+export const isPlainTextElement = makeMap('script,style,textarea', true)
 const reCache = {}
 
 const decodingMap = {

src/compiler/parser/index.js

@@ -252,7 +252,7 @@ export function parse (
       }
       const children = currentParent.children
       text = inPre || text.trim()
-        ? decodeHTMLCached(text)
+        ? isTextTag(currentParent) ? text : decodeHTMLCached(text)
         // only preserve whitespace if its not right after a starting tag
         : preserveWhitespace && children.length ? ' ' : ''
       if (text) {
@@ -544,6 +544,11 @@ function makeAttrsMap (attrs: Array<Object>): Object {
   return map
 }
 
+// for script (e.g. type="x/template") or style, do not decode content
+function isTextTag (el): boolean {
+  return el.tag === 'script' || el.tag === 'style'
+}
+
 function isForbiddenTag (el): boolean {
   return (
     el.tag === 'style' ||

test/unit/modules/compiler/parser.spec.js

@@ -541,4 +541,11 @@ describe('parser', () => {
     expect(comment.children[0].type).toBe(3)
     expect(comment.children[0].text).toBe('<!--comment-->')
   })
+
+  // #5526
+  it('should not decode text in script tags', () => {
+    const options = extend({}, baseOptions)
+    const ast = parse(`<script type="x/template">&gt;<foo>&lt;</script>`, options)
+    expect(ast.children[0].text).toBe(`&gt;<foo>&lt;`)
+  })
 })