From 9340fed9d874d4f3c0ea22b6d4c0ad5254fa5f02 Mon Sep 17 00:00:00 2001
From: Brett Zamir <brettz9@yahoo.com>
Date: Thu, 19 Sep 2024 07:10:53 +0800
Subject: [PATCH] fix(`require-returns-check`): allow infinite for loops to
 have only one branch to return; fixes #1315

---
 docs/rules/require-returns-check.md          | 12 ++++++++++++
 src/utils/hasReturnValue.js                  |  7 ++++++-
 test/rules/assertions/requireReturnsCheck.js | 15 +++++++++++++++
 3 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/docs/rules/require-returns-check.md b/docs/rules/require-returns-check.md
index 2ff2b6c1..fab817d6 100644
--- a/docs/rules/require-returns-check.md
+++ b/docs/rules/require-returns-check.md
@@ -992,5 +992,17 @@ function foo() {
     }
   }
 }
+
+/**
+ * @returns {number}
+ */
+function foo() {
+  for (;;) {
+    const n = Math.random();
+    if (n < 0.5) {
+      return n;
+    }
+  }
+}
 ````
 
diff --git a/src/utils/hasReturnValue.js b/src/utils/hasReturnValue.js
index 1809cabc..a481ee17 100644
--- a/src/utils/hasReturnValue.js
+++ b/src/utils/hasReturnValue.js
@@ -177,8 +177,13 @@ const allBrancheshaveReturnValues = (node, promFilter) => {
     }
 
     // Fallthrough
-  case 'LabeledStatement':
   case 'ForStatement':
+    if (node.test === null) {
+      // If this is an infinite loop, we assume only one branch
+      //   is needed to provide a return
+      return hasReturnValue(node.body, false, promFilter);
+    }
+  case 'LabeledStatement':
   case 'ForInStatement':
   case 'ForOfStatement':
   case 'WithStatement': {
diff --git a/test/rules/assertions/requireReturnsCheck.js b/test/rules/assertions/requireReturnsCheck.js
index 025d6ab1..f9547281 100755
--- a/test/rules/assertions/requireReturnsCheck.js
+++ b/test/rules/assertions/requireReturnsCheck.js
@@ -1558,5 +1558,20 @@ export default {
         }
       `,
     },
+    {
+      code: `
+        /**
+         * @returns {number}
+         */
+        function foo() {
+          for (;;) {
+            const n = Math.random();
+            if (n < 0.5) {
+              return n;
+            }
+          }
+        }
+      `,
+    },
   ],
 };