disable REPL completion on proxies and getters

lib/repl.js

@@ -96,6 +96,10 @@ const {
   globalThis,
 } = primordials;
 
+const {
+  isProxy,
+} = require('internal/util/types');
+
 const { BuiltinModule } = require('internal/bootstrap/realm');
 const {
   makeRequireFunction,
@@ -1328,8 +1332,10 @@ function completeFSFunctions(match) {
 //    -> [['util.print', 'util.debug', 'util.log', 'util.inspect'],
 //        'util.' ]
 //
-// Warning: This eval's code like "foo.bar.baz", so it will run property
-// getter code.
+// Warning: This evals code like "foo.bar.baz", so it could run property
+// getter code. To avoid potential triggering side-effects with getters the completion
+// logic is skipped when getters or proxies are involved in the expression.
+// (see: https://github.com/nodejs/node/issues/57829).
 function complete(line, callback) {
   // List of completion lists, one for each inheritance "level"
   let completionGroups = [];
@@ -1525,50 +1531,61 @@ function complete(line, callback) {
       return;
     }
 
-    let chaining = '.';
-    if (StringPrototypeEndsWith(expr, '?')) {
-      expr = StringPrototypeSlice(expr, 0, -1);
-      chaining = '?.';
-    }
-
-    const memberGroups = [];
-    const evalExpr = `try { ${expr} } catch {}`;
-    this.eval(evalExpr, this.context, getREPLResourceName(), (e, obj) => {
-      try {
-        let p;
-        if ((typeof obj === 'object' && obj !== null) ||
-            typeof obj === 'function') {
-          ArrayPrototypePush(memberGroups, filteredOwnPropertyNames(obj));
-          p = ObjectGetPrototypeOf(obj);
-        } else {
-          p = obj.constructor ? obj.constructor.prototype : null;
+    return includesProxiesOrGetters(
+      StringPrototypeSplit(match, '.'),
+      this.eval,
+      this.context,
+      (includes) => {
+        if (includes) {
+        // The expression involves proxies or getters, meaning that it
+        // can trigger side-effectful behaviors, so bail out
+          return completionGroupsLoaded();
         }
-        // Circular refs possible? Let's guard against that.
-        let sentinel = 5;
-        while (p !== null && sentinel-- !== 0) {
-          ArrayPrototypePush(memberGroups, filteredOwnPropertyNames(p));
-          p = ObjectGetPrototypeOf(p);
+
+        let chaining = '.';
+        if (StringPrototypeEndsWith(expr, '?')) {
+          expr = StringPrototypeSlice(expr, 0, -1);
+          chaining = '?.';
         }
-      } catch {
-        // Maybe a Proxy object without `getOwnPropertyNames` trap.
-        // We simply ignore it here, as we don't want to break the
-        // autocompletion. Fixes the bug
-        // https://github.com/nodejs/node/issues/2119
-      }
 
-      if (memberGroups.length) {
-        expr += chaining;
-        ArrayPrototypeForEach(memberGroups, (group) => {
-          ArrayPrototypePush(completionGroups,
-                             ArrayPrototypeMap(group,
-                                               (member) => `${expr}${member}`));
-        });
-        filter &&= `${expr}${filter}`;
-      }
+        const memberGroups = [];
+        const evalExpr = `try { ${expr} } catch {}`;
+        this.eval(evalExpr, this.context, getREPLResourceName(), (e, obj) => {
+          try {
+            let p;
+            if ((typeof obj === 'object' && obj !== null) ||
+              typeof obj === 'function') {
+              ArrayPrototypePush(memberGroups, filteredOwnPropertyNames(obj));
+              p = ObjectGetPrototypeOf(obj);
+            } else {
+              p = obj.constructor ? obj.constructor.prototype : null;
+            }
+            // Circular refs possible? Let's guard against that.
+            let sentinel = 5;
+            while (p !== null && sentinel-- !== 0) {
+              ArrayPrototypePush(memberGroups, filteredOwnPropertyNames(p));
+              p = ObjectGetPrototypeOf(p);
+            }
+          } catch {
+          // Maybe a Proxy object without `getOwnPropertyNames` trap.
+          // We simply ignore it here, as we don't want to break the
+          // autocompletion. Fixes the bug
+          // https://github.com/nodejs/node/issues/2119
+          }
 
-      completionGroupsLoaded();
-    });
-    return;
+          if (memberGroups.length) {
+            expr += chaining;
+            ArrayPrototypeForEach(memberGroups, (group) => {
+              ArrayPrototypePush(completionGroups,
+                                 ArrayPrototypeMap(group,
+                                                   (member) => `${expr}${member}`));
+            });
+            filter &&= `${expr}${filter}`;
+          }
+
+          completionGroupsLoaded();
+        });
+      });
   }
 
   return completionGroupsLoaded();
@@ -1626,6 +1643,34 @@ function complete(line, callback) {
   }
 }
 
+function includesProxiesOrGetters(exprSegments, evalFn, context, callback, currentExpr = '', idx = 0) {
+  const currentSegment = exprSegments[idx];
+  currentExpr += `${currentExpr.length === 0 ? '' : '.'}${currentSegment}`;
+  evalFn(`try { ${currentExpr} } catch { }`, context, getREPLResourceName(), (_, currentObj) => {
+    if (typeof currentObj !== 'object' || currentObj === null) {
+      return callback(false);
+    }
+
+    if (isProxy(currentObj)) {
+      return callback(true);
+    }
+
+    const nextIdx = idx + 1;
+
+    if (nextIdx >= exprSegments.length) {
+      return callback(false);
+    }
+
+    const nextSegmentProp = ObjectGetOwnPropertyDescriptor(currentObj, exprSegments[nextIdx]);
+    const nextSegmentPropHasGetter = typeof nextSegmentProp?.get === 'function';
+    if (nextSegmentPropHasGetter) {
+      return callback(true);
+    }
+
+    return includesProxiesOrGetters(exprSegments, evalFn, context, callback, currentExpr, nextIdx);
+  });
+}
+
 REPLServer.prototype.completeOnEditorMode = (callback) => (err, results) => {
   if (err) return callback(err);
 

test/parallel/test-repl-completion-on-getters-disabled.js

@@ -0,0 +1,119 @@
+'use strict';
+
+const common = require('../common');
+const assert = require('node:assert');
+const { describe, test } = require('node:test');
+
+const ArrayStream = require('../common/arraystream');
+
+const repl = require('node:repl');
+
+function runCompletionTests(replInit, tests) {
+  const stream = new ArrayStream();
+  const testRepl = repl.start({ stream });
+
+  // Some errors are passed to the domain
+  testRepl._domain.on('error', assert.ifError);
+
+  testRepl.write(replInit);
+  testRepl.write('\n');
+
+  tests.forEach(([query, expectedCompletions]) => {
+    testRepl.complete(query, common.mustCall((error, data) => {
+      const actualCompletions = data[0];
+      if (expectedCompletions.length === 0) {
+        assert.deepStrictEqual(actualCompletions, []);
+      } else {
+        expectedCompletions.forEach((expectedCompletion) =>
+          assert(actualCompletions.includes(expectedCompletion), `completion '${expectedCompletion}' not found`)
+        );
+      }
+    }));
+  });
+}
+
+describe('REPL completion in relation of getters', () => {
+  describe('standard behavior without proxies/getters', () => {
+    test('completion of nested properties of an undeclared objects', () => {
+      runCompletionTests('', [
+        ['nonExisting.', []],
+        ['nonExisting.f', []],
+        ['nonExisting.foo', []],
+        ['nonExisting.foo.', []],
+        ['nonExisting.foo.bar.b', []],
+      ]);
+    });
+
+    test('completion of nested properties on plain objects', () => {
+      runCompletionTests('const plainObj = { foo: { bar: { baz: {} } } };', [
+        ['plainObj.', ['plainObj.foo']],
+        ['plainObj.f', ['plainObj.foo']],
+        ['plainObj.foo', ['plainObj.foo']],
+        ['plainObj.foo.', ['plainObj.foo.bar']],
+        ['plainObj.foo.bar.b', ['plainObj.foo.bar.baz']],
+        ['plainObj.fooBar.', []],
+        ['plainObj.fooBar.baz', []],
+      ]);
+    });
+  });
+
+  describe('completions on an object with getters', () => {
+    test(`completions are generated for properties that don't trigger getters`, () => {
+      runCompletionTests(
+        `
+        const objWithGetters = {
+          foo: { bar: { baz: {} }, get gBar() { return { baz: {} } } },
+          get gFoo() { return { bar: { baz: {} } }; }
+        };
+        `, [
+          ['objWithGetters.', ['objWithGetters.foo']],
+          ['objWithGetters.f', ['objWithGetters.foo']],
+          ['objWithGetters.foo', ['objWithGetters.foo']],
+          ['objWithGetters.foo.', ['objWithGetters.foo.bar']],
+          ['objWithGetters.foo.bar.b', ['objWithGetters.foo.bar.baz']],
+          ['objWithGetters.gFo', ['objWithGetters.gFoo']],
+          ['objWithGetters.foo.gB', ['objWithGetters.foo.gBar']],
+        ]);
+    });
+
+    test('no completions are generated for properties that trigger getters', () => {
+      runCompletionTests(
+        `
+        const objWithGetters = {
+          foo: { bar: { baz: {} }, get gBar() { return { baz: {} } } },
+          get gFoo() { return { bar: { baz: {} } }; }
+        };
+        `,
+        [
+          ['objWithGetters.gFoo.', []],
+          ['objWithGetters.gFoo.b', []],
+          ['objWithGetters.gFoo.bar.b', []],
+          ['objWithGetters.foo.gBar.', []],
+          ['objWithGetters.foo.gBar.b', []],
+        ]);
+    });
+  });
+
+  describe('completions on proxies', () => {
+    test('no completions are generated for a proxy object', () => {
+      runCompletionTests('const proxyObj = new Proxy({ foo: { bar: { baz: {} } } }, {});', [
+        ['proxyObj.', []],
+        ['proxyObj.f', []],
+        ['proxyObj.foo', []],
+        ['proxyObj.foo.', []],
+        ['proxyObj.foo.bar.b', []],
+      ]);
+    });
+
+    test('no completions are generated for a proxy present in a standard object', () => {
+      runCompletionTests(
+        'const objWithProxy = { foo: { bar: new Proxy({ baz: {} }, {}) } };', [
+          ['objWithProxy.', ['objWithProxy.foo']],
+          ['objWithProxy.foo', ['objWithProxy.foo']],
+          ['objWithProxy.foo.', ['objWithProxy.foo.bar']],
+          ['objWithProxy.foo.b', ['objWithProxy.foo.bar']],
+          ['objWithProxy.foo.bar.', []],
+        ]);
+    });
+  });
+});