Fix a false positive

eslint · May 1, 2023 · cd6cb7b · cd6cb7b
1 parent 66b6181
commit cd6cb7b
Show file tree

Hide file tree

Showing 2 changed files with 21 additions and 8 deletions.
diff --git a/lib/rules/no-useless-return.js b/lib/rules/no-useless-return.js
@@ -82,7 +82,6 @@ module.exports = {
 
     create(context) {
         const segmentInfoMap = new WeakMap();
-        const usedUnreachableSegments = new WeakSet();
         const sourceCode = context.getSourceCode();
         let scopeInfo = null;
 
@@ -152,21 +151,22 @@ module.exports = {
          * This behavior would simulate code paths for the case that the return
          * statement does not exist.
          * @param {CodePathSegment} segment The segment to get return statements.
+         * @param {Set<CodePathSegment>} usedUnreachableSegments A set of segments that have already been traversed in this call.
          * @returns {void}
          */
-        function markReturnStatementsOnSegmentAsUsed(segment) {
+        function markReturnStatementsOnSegmentAsUsed(segment, usedUnreachableSegments) {
             if (!segment.reachable) {
                 usedUnreachableSegments.add(segment);
                 segment.allPrevSegments
                     .filter(isReturned)
                     .filter(prevSegment => !usedUnreachableSegments.has(prevSegment))
-                    .forEach(markReturnStatementsOnSegmentAsUsed);
+                    .forEach(prevSegment => markReturnStatementsOnSegmentAsUsed(prevSegment, usedUnreachableSegments));
                 return;
             }
 
             const info = segmentInfoMap.get(segment);
 
-            for (const node of info.uselessReturns) {
+            info.uselessReturns = info.uselessReturns.filter(node => {
                 if (scopeInfo.traversedTryBlockStatements && scopeInfo.traversedTryBlockStatements.length > 0) {
                     const returnInitialRange = node.range[0];
                     const returnFinalRange = node.range[1];
@@ -182,13 +182,13 @@ module.exports = {
                     });
 
                     if (areBlocksInRange) {
-                        continue;
+                        return true;
                     }
                 }
 
                 remove(scopeInfo.uselessReturns, node);
-            }
-            info.uselessReturns = [];
+                return false;
+            });
         }
 
         /**
@@ -207,7 +207,7 @@ module.exports = {
             scopeInfo
                 .codePath
                 .currentSegments
-                .forEach(markReturnStatementsOnSegmentAsUsed);
+                .forEach(segment => markReturnStatementsOnSegmentAsUsed(segment, new Set()));
         }
 
         //----------------------------------------------------------------------

diff --git a/tests/lib/rules/no-useless-return.js b/tests/lib/rules/no-useless-return.js
@@ -195,6 +195,19 @@ ruleTester.run("no-useless-return", rule, {
             }
             console.log(arg);
           }
+        `,
+
+        // https://github.com/eslint/eslint/pull/16996#discussion_r1138622844
+        `
+        function foo() {
+          try {
+              bar();
+              return;
+          } finally {
+              baz();
+          }
+          qux();
+        }
         `
     ],