fix(ssr): handle initial selected state for select with v-model + v-for/v-if option

Author: edison1105

packages/compiler-ssr/__tests__/ssrVModel.spec.ts

@@ -166,6 +166,62 @@ describe('ssr: v-model', () => {
         _push(\`</optgroup></select></div>\`)
       }"
     `)
+
+    expect(
+      compileWithWrapper(`
+        <select multiple v-model="model">
+          <optgroup>
+            <option v-for="item in items" :value="item">{{item}}</option>
+          </optgroup>
+        </select>`).code,
+    ).toMatchInlineSnapshot(`
+      "const { ssrRenderAttr: _ssrRenderAttr, ssrIncludeBooleanAttr: _ssrIncludeBooleanAttr, ssrLooseContain: _ssrLooseContain, ssrLooseEqual: _ssrLooseEqual, ssrRenderAttrs: _ssrRenderAttrs, ssrInterpolate: _ssrInterpolate, ssrRenderList: _ssrRenderList } = require("vue/server-renderer")
+
+      return function ssrRender(_ctx, _push, _parent, _attrs) {
+        _push(\`<div\${_ssrRenderAttrs(_attrs)}><select multiple><optgroup><!--[-->\`)
+        _ssrRenderList(_ctx.items, (item) => {
+          _push(\`<option\${
+            _ssrRenderAttr("value", item)
+          }\${
+            (_ssrIncludeBooleanAttr((Array.isArray(_ctx.model))
+              ? _ssrLooseContain(_ctx.model, item)
+              : _ssrLooseEqual(_ctx.model, item))) ? " selected" : ""
+          }>\${
+            _ssrInterpolate(item)
+          }</option>\`)
+        })
+        _push(\`<!--]--></optgroup></select></div>\`)
+      }"
+    `)
+
+    expect(
+      compileWithWrapper(`
+        <select multiple v-model="model">
+          <optgroup>
+            <option v-if="true" :value="item">{{item}}</option>
+          </optgroup>
+        </select>`).code,
+    ).toMatchInlineSnapshot(`
+      "const { ssrRenderAttr: _ssrRenderAttr, ssrIncludeBooleanAttr: _ssrIncludeBooleanAttr, ssrLooseContain: _ssrLooseContain, ssrLooseEqual: _ssrLooseEqual, ssrRenderAttrs: _ssrRenderAttrs, ssrInterpolate: _ssrInterpolate } = require("vue/server-renderer")
+
+      return function ssrRender(_ctx, _push, _parent, _attrs) {
+        _push(\`<div\${_ssrRenderAttrs(_attrs)}><select multiple><optgroup>\`)
+        if (true) {
+          _push(\`<option\${
+            _ssrRenderAttr("value", _ctx.item)
+          }\${
+            (_ssrIncludeBooleanAttr((Array.isArray(_ctx.model))
+              ? _ssrLooseContain(_ctx.model, _ctx.item)
+              : _ssrLooseEqual(_ctx.model, _ctx.item))) ? " selected" : ""
+          }>\${
+            _ssrInterpolate(_ctx.item)
+          }</option>\`)
+        } else {
+          _push(\`<!---->\`)
+        }
+        _push(\`</optgroup></select></div>\`)
+      }"
+    `)
   })
 
   test('<input type="radio">', () => {

packages/compiler-ssr/src/transforms/ssrVModel.ts

@@ -65,9 +65,17 @@ export const ssrTransformModel: DirectiveTransform = (dir, node, context) => {
         )
       }
     } else if (plainNode.tag === 'optgroup') {
-      plainNode.children.forEach(option =>
-        processOption(option as PlainElementNode),
-      )
+      plainNode.children.forEach(option => {
+        if (option.type === NodeTypes.ELEMENT) {
+          processOption(option as PlainElementNode)
+        } else if (option.type === NodeTypes.FOR) {
+          option.children.forEach(c => processOption(c as PlainElementNode))
+        } else if (option.type === NodeTypes.IF) {
+          option.branches.forEach(b =>
+            b.children.forEach(c => processOption(c as PlainElementNode)),
+          )
+        }
+      })
     }
   }