fix(compiler-core): the component always uses the NEED_PATCH flag to avoid patch errors

packages/compiler-core/__tests__/__snapshots__/scopeId.spec.ts.snap

@@ -30,7 +30,7 @@ export const render = /*#__PURE__*/_withId(function render(_ctx, _cache) {
       _createVNode(\\"div\\")
     ]),
     _: 1
-  }))
+  }, 512 /* NEED_PATCH */))
 })"
 `;
 
@@ -77,7 +77,7 @@ export const render = /*#__PURE__*/_withId(function render(_ctx, _cache) {
       _createVNode(\\"div\\")
     ]),
     _: 1
-  }))
+  }, 512 /* NEED_PATCH */))
 })"
 `;
 

packages/compiler-core/__tests__/transforms/__snapshots__/hoistStatic.spec.ts.snap

@@ -144,7 +144,7 @@ return function render(_ctx, _cache) {
 
     return (_openBlock(), _createBlock(\\"div\\", null, [
       _createVNode(\\"div\\", _hoisted_1, [
-        _createVNode(_component_Comp)
+        _createVNode(_component_Comp, null, null, 512 /* NEED_PATCH */)
       ])
     ]))
   }
@@ -248,7 +248,7 @@ return function render(_ctx, _cache) {
         _createTextVNode(_toDisplayString(_ctx.foo), 1 /* TEXT */)
       ]),
       _: 1
-    }))
+    }, 512 /* NEED_PATCH */))
   }
 }"
 `;
@@ -297,7 +297,7 @@ return function render(_ctx, _cache) {
     const _component_Comp = _resolveComponent(\\"Comp\\")
 
     return (_openBlock(), _createBlock(\\"div\\", null, [
-      _createVNode(_component_Comp)
+      _createVNode(_component_Comp, null, null, 512 /* NEED_PATCH */)
     ]))
   }
 }"

packages/compiler-core/__tests__/transforms/__snapshots__/vSlot.spec.ts.snap

@@ -25,7 +25,7 @@ return function render(_ctx, _cache) {
       _createVNode(\\"div\\")
     ]),
     _: 1
-  }))
+  }, 512 /* NEED_PATCH */))
 }"
 `;
 
@@ -129,7 +129,7 @@ return function render(_ctx, _cache) {
         _createVNode(\\"span\\")
       ]),
       _: 1
-    }))
+    }, 512 /* NEED_PATCH */))
   }
 }"
 `;
@@ -153,7 +153,7 @@ return function render(_ctx, _cache) {
       _toDisplayString(_ctx.baz)
     ]),
     _: 1
-  }))
+  }, 512 /* NEED_PATCH */))
 }"
 `;
 
@@ -179,7 +179,7 @@ return function render(_ctx, _cache) {
   return (_openBlock(), _createBlock(_component_Comp, null, {
     named: _withCtx(({ foo }) => [_toDisplayString(foo), _toDisplayString(_ctx.bar)]),
     _: 1
-  }))
+  }, 512 /* NEED_PATCH */))
 }"
 `;
 
@@ -192,7 +192,7 @@ return function render(_ctx, _cache) {
   return (_openBlock(), _createBlock(_component_Comp, null, {
     default: _withCtx(({ foo }) => [_toDisplayString(foo), _toDisplayString(_ctx.bar)]),
     _: 1
-  }))
+  }, 512 /* NEED_PATCH */))
 }"
 `;
 
@@ -206,6 +206,6 @@ return function render(_ctx, _cache) {
     one: _withCtx(({ foo }) => [_toDisplayString(foo), _toDisplayString(_ctx.bar)]),
     two: _withCtx(({ bar }) => [_toDisplayString(_ctx.foo), _toDisplayString(bar)]),
     _: 1
-  }))
+  }, 512 /* NEED_PATCH */))
 }"
 `;

packages/compiler-core/__tests__/transforms/vSlot.spec.ts

@@ -486,7 +486,7 @@ describe('compiler: transform component slots', () => {
       if (shouldForce) {
         expect(flag).toBe(genFlagText(PatchFlags.DYNAMIC_SLOTS))
       } else {
-        expect(flag).toBeUndefined()
+        expect(flag).toBe(genFlagText(PatchFlags.NEED_PATCH))
       }
     }
 

packages/compiler-core/src/transforms/transformElement.ts

@@ -26,6 +26,7 @@ import {
   isSymbol,
   isOn,
   isObject,
+  isString,
   isReservedProp
 } from '@vue/shared'
 import { createCompilerError, ErrorCodes } from '../errors'
@@ -176,6 +177,17 @@ export const transformElement: NodeTransform = (node, context) => {
       }
     }
 
+    // #2058
+    // when the component is not registered, it will resolve to plain element,
+    // we add the `NEED_PATCH` flag here to avoid accidental failure of tracking.
+    if (
+      isString(vnodeTag) &&
+      /^_component_/.test(vnodeTag) &&
+      patchFlag === 0
+    ) {
+      patchFlag |= PatchFlags.NEED_PATCH
+    }
+
     // patchFlag & dynamicPropNames
     if (patchFlag !== 0) {
       if (__DEV__) {

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

@@ -120,7 +120,7 @@ describe('ssr: scopeId', () => {
                     _createVNode(\\"span\\")
                   ]),
                   _: 1
-                })
+                }, 512 /* NEED_PATCH */)
               ]
             }
           }),