From fd410f43fcb771aa38215d17d7a487d1bc789d71 Mon Sep 17 00:00:00 2001
From: Dan Abramov <dan.abramov@gmail.com>
Date: Mon, 16 Jul 2018 22:47:37 +0100
Subject: [PATCH] Protect against passing component stack twice

This is a leftover from #13161 that I forgot to include.
It ensures we don't accidentally write code in the old way and end up passing the stack twice.
---
 .../jest/matchers/__tests__/toWarnDev-test.js |  8 +++++
 scripts/jest/matchers/toWarnDev.js            | 30 ++++++++++++++++++-
 2 files changed, 37 insertions(+), 1 deletion(-)

diff --git a/scripts/jest/matchers/__tests__/toWarnDev-test.js b/scripts/jest/matchers/__tests__/toWarnDev-test.js
index 67f4c99e97..d5ef59abe6 100644
--- a/scripts/jest/matchers/__tests__/toWarnDev-test.js
+++ b/scripts/jest/matchers/__tests__/toWarnDev-test.js
@@ -161,5 +161,13 @@ describe('toWarnDev', () => {
         }).toWarnDev('Hi', {withoutStack: true});
       }).toThrow('Received 0 arguments for a message with 1 placeholders');
     });
+
+    it('fails if stack is passed twice', () => {
+      expect(() => {
+        expect(() => {
+          console.error('Hi %s%s', '\n    in div', '\n    in div');
+        }).toWarnDev('Hi');
+      }).toThrow('Received more than one component stack for a warning');
+    });
   }
 });
diff --git a/scripts/jest/matchers/toWarnDev.js b/scripts/jest/matchers/toWarnDev.js
index 6404a54c7b..187de91e54 100644
--- a/scripts/jest/matchers/toWarnDev.js
+++ b/scripts/jest/matchers/toWarnDev.js
@@ -24,7 +24,9 @@ const createMatcherFor = consoleMethod =>
       const warningsWithoutComponentStack = [];
       const warningsWithComponentStack = [];
       const unexpectedWarnings = [];
+
       let lastWarningWithMismatchingFormat = null;
+      let lastWarningWithExtraComponentStack = null;
 
       // Catch errors thrown by the callback,
       // But only rethrow them if all test expectations have been satisfied.
@@ -32,6 +34,9 @@ const createMatcherFor = consoleMethod =>
       // and result in a test that passes when it shouldn't.
       let caughtError;
 
+      const isLikelyAComponentStack = message =>
+        typeof message === 'string' && message.includes('\n    in ');
+
       const consoleSpy = (format, ...args) => {
         const message = util.format(format, ...args);
         const normalizedMessage = normalizeCodeLocInfo(message);
@@ -49,13 +54,25 @@ const createMatcherFor = consoleMethod =>
           };
         }
 
+        // Protect against accidentally passing a component stack
+        // to warning() which already injects the component stack.
+        if (
+          args.length >= 2 &&
+          isLikelyAComponentStack(args[args.length - 1]) &&
+          isLikelyAComponentStack(args[args.length - 2])
+        ) {
+          lastWarningWithExtraComponentStack = {
+            format,
+          };
+        }
+
         for (let index = 0; index < expectedMessages.length; index++) {
           const expectedMessage = expectedMessages[index];
           if (
             normalizedMessage === expectedMessage ||
             normalizedMessage.includes(expectedMessage)
           ) {
-            if (normalizedMessage.includes('\n    in ')) {
+            if (isLikelyAComponentStack(normalizedMessage)) {
               warningsWithComponentStack.push(normalizedMessage);
             } else {
               warningsWithoutComponentStack.push(normalizedMessage);
@@ -191,6 +208,17 @@ const createMatcherFor = consoleMethod =>
           };
         }
 
+        if (lastWarningWithExtraComponentStack !== null) {
+          return {
+            message: () =>
+              `Received more than one component stack for a warning:\n  ${this.utils.printReceived(
+                lastWarningWithExtraComponentStack.format
+              )}\nDid you accidentally pass a stack to warning() as the last argument? ` +
+              `Don't forget warning() already injects the component stack automatically.`,
+            pass: false,
+          };
+        }
+
         return {pass: true};
       }
     } else {