fix: no warn if pathMatch is empty

Author: yinm

Diff for: src/util/params.js

@@ -24,7 +24,10 @@ export function fillParams (
 
     return filler(params, { pretty: true })
   } catch (e) {
-    if (process.env.NODE_ENV !== 'production') {
+    if (
+      process.env.NODE_ENV !== 'production' &&
+      params.pathMatch !== '' // Fix #3072 no warn if `pathMatch` is empty
+    ) {
       warn(false, `missing param for ${routeMsg}: ${e.message}`)
     }
     return ''

Diff for: test/unit/specs/create-matcher.spec.js

@@ -71,6 +71,15 @@ describe('Creating Matcher', function () {
     expect(path).toEqual('/error/some')
   })
 
+  it('matches named catch-all route with empty pathMath param without warning', function () {
+    process.env.NODE_ENV = 'development'
+    match(
+      { name: 'notFound', params: { pathMatch: '' }},
+      routes[0]
+    )
+    expect(console.warn).not.toHaveBeenCalled()
+  })
+
   it('matches asterisk routes with a default param name', function () {
     const { params } = match({ path: '/not-found' }, routes[0])
     expect(params).toEqual({ pathMatch: '/not-found' })