From 2d6e1f66f10e2fca95a503cf56db3feb78bb746d Mon Sep 17 00:00:00 2001
From: Alex Ilyaev <alexilyaev@gmail.com>
Date: Mon, 17 Jul 2017 16:13:44 +0300
Subject: [PATCH] Redirect: Support props changes on Redirect to handle edge
 cases

---
 packages/react-router/modules/Redirect.js     |  24 ++++-
 .../modules/__tests__/Switch-test.js          | 100 ++++++++++++++++++
 2 files changed, 122 insertions(+), 2 deletions(-)

diff --git a/packages/react-router/modules/Redirect.js b/packages/react-router/modules/Redirect.js
index 87fe342789..ee7fe44f51 100644
--- a/packages/react-router/modules/Redirect.js
+++ b/packages/react-router/modules/Redirect.js
@@ -1,9 +1,11 @@
 import React from 'react'
 import PropTypes from 'prop-types'
+import warning from 'warning'
 import invariant from 'invariant'
+import { locationsAreEqual } from 'history'
 
 /**
- * The public API for updating the location programatically
+ * The public API for updating the location programmatically
  * with a component.
  */
 class Redirect extends React.Component {
@@ -13,7 +15,7 @@ class Redirect extends React.Component {
     to: PropTypes.oneOfType([
       PropTypes.string,
       PropTypes.object
-    ])
+    ]).isRequired
   }
 
   static defaultProps = {
@@ -49,6 +51,24 @@ class Redirect extends React.Component {
       this.perform()
   }
 
+  componentDidUpdate(prevProps) {
+    let prevTo = prevProps.to
+    let nextTo = this.props.to
+
+    prevTo = typeof prevTo === 'string' ? { pathname: prevTo } : prevTo
+    nextTo = typeof nextTo === 'string' ? { pathname: nextTo } : nextTo
+
+    if (locationsAreEqual(prevTo, nextTo))
+      return warning(
+        false,
+        `You tried to redirect to the same route you're currently on: "%s%s"`,
+        nextTo.pathname,
+        nextTo.search || ''
+      )
+
+    this.perform()
+  }
+
   perform() {
     const { history } = this.context.router
     const { push, to } = this.props
diff --git a/packages/react-router/modules/__tests__/Switch-test.js b/packages/react-router/modules/__tests__/Switch-test.js
index 76c006a24a..3a8ce54c63 100644
--- a/packages/react-router/modules/__tests__/Switch-test.js
+++ b/packages/react-router/modules/__tests__/Switch-test.js
@@ -102,6 +102,106 @@ describe('A <Switch>', () => {
     expect(node.innerHTML).toContain('bub')
   })
 
+  it('handles subsequent redirects', () => {
+    const node = document.createElement('div')
+
+    ReactDOM.render((
+      <MemoryRouter initialEntries={[ '/one' ]}>
+        <Switch>
+          <Redirect exact from="/one" to="/two"/>
+          <Redirect exact from="/two" to="/three"/>
+
+          <Route path="/three" render={() => <div>three</div>}/>
+        </Switch>
+      </MemoryRouter>
+    ), node)
+
+    expect(node.innerHTML).toContain('three')
+  })
+
+  it('warns when redirecting to same route, both strings', () => {
+    const node = document.createElement('div')
+    let redirected = false
+
+    expect.spyOn(console, 'error')
+
+    ReactDOM.render((
+      <MemoryRouter initialEntries={[ '/one' ]}>
+        <Switch>
+          <Route path="/one" render={() => {
+            if (!redirected) {
+              return <Redirect to="/one"/>
+            }
+
+            return <Redirect to='/one'/>
+          }}/>
+        </Switch>
+      </MemoryRouter>
+    ), node)
+
+    expect(console.error.calls.length).toBe(1)
+    expect(console.error.calls[0].arguments[0]).toMatch(/Warning:.*"\/one"/)
+    expect.restoreSpies()
+  })
+
+  it('warns when redirecting to same route, mixed types', () => {
+    const node = document.createElement('div')
+    let redirected = false
+
+    expect.spyOn(console, 'error')
+
+    ReactDOM.render((
+      <MemoryRouter initialEntries={[ '/one' ]}>
+        <Switch>
+          <Route path="/one" render={() => {
+            if (!redirected) {
+              redirected = true
+              return <Redirect to="/one"/>
+            }
+
+            return <Redirect to={{pathname: '/one'}}/>
+          }}/>
+        </Switch>
+      </MemoryRouter>
+    ), node)
+
+    expect(console.error.calls.length).toBe(1)
+    expect(console.error.calls[0].arguments[0]).toMatch(/Warning:.*"\/one"/)
+    expect.restoreSpies()
+  })
+
+  it('does NOT warn when redirecting to same route with different `search`', () => {
+    const node = document.createElement('div')
+    let redirected = false
+    let done = false
+
+    expect.spyOn(console, 'error')
+
+    ReactDOM.render((
+      <MemoryRouter initialEntries={[ '/one' ]}>
+        <Switch>
+          <Route path="/one" render={() => {
+            if (done)
+              return <h1>done</h1>
+
+            if (!redirected) {
+              redirected = true
+              return <Redirect to={{pathname: '/one', search: '?utm=1'}}/>
+            }
+
+            done = true
+
+            return <Redirect to={{pathname: '/one', search: '?utm=2'}}/>
+          }}/>
+        </Switch>
+      </MemoryRouter>
+    ), node)
+
+    expect(node.innerHTML).toContain('done')
+    expect(console.error.calls.length).toBe(0)
+    expect.restoreSpies()
+  })
+
   it('handles comments', () => {
     const node = document.createElement('div')