tools: prevent string literals in some assertions

String literals provided as the third argument to assert.strictEqual()
or assert.deepStrictEqual() will mask the values that are causing
issues. Use a lint rule to prevent such usage.

Backport-PR-URL: #22912
PR-URL: #22849
Reviewed-By: Teddy Katz <[email protected]>
Reviewed-By: Matteo Collina <[email protected]>
Reviewed-By: Anna Henningsen <[email protected]>
Reviewed-By: Trivikram Kamat <[email protected]>
Reviewed-By: Luigi Pinca <[email protected]>
Reviewed-By: Colin Ihrig <[email protected]>

Author: Trott

.eslintrc.js

@@ -156,6 +156,7 @@ module.exports = {
     ],
     /* eslint-disable max-len */
     // If this list is modified, please copy the change to lib/.eslintrc.yaml
+    // and test/.eslintrc.yaml.
     'no-restricted-syntax': [
       'error',
       {
@@ -166,6 +167,10 @@ module.exports = {
         selector: "CallExpression[callee.object.name='assert'][callee.property.name='rejects'][arguments.length<2]",
         message: 'assert.rejects() must be invoked with at least two arguments.',
       },
+      {
+        selector: "CallExpression[callee.object.name='assert'][callee.property.name='strictEqual'][arguments.2.type='Literal']",
+        message: 'Do not use a literal for the third argument of assert.strictEqual()'
+      },
       {
         selector: "CallExpression[callee.object.name='assert'][callee.property.name='throws'][arguments.1.type='Literal']:not([arguments.1.regex])",
         message: 'Use an object as second argument of assert.throws()',

lib/.eslintrc.yaml

@@ -2,10 +2,14 @@ rules:
   no-restricted-syntax:
     # Config copied from .eslintrc.js
     - error
+    - selector: "CallExpression[callee.object.name='assert'][callee.property.name='deepStrictEqual'][arguments.2.type='Literal']"
+      message: "Do not use a literal for the third argument of assert.deepStrictEqual()"
     - selector: "CallExpression[callee.object.name='assert'][callee.property.name='doesNotThrow']"
       message: "Please replace `assert.doesNotThrow()` and add a comment next to the code instead."
     - selector: "CallExpression[callee.object.name='assert'][callee.property.name='rejects'][arguments.length<2]"
       message: "assert.rejects() must be invoked with at least two arguments."
+    - selector: "CallExpression[callee.object.name='assert'][callee.property.name='strictEqual'][arguments.2.type='Literal']"
+      message: "Do not use a literal for the third argument of assert.strictEqual()"
     - selector: "CallExpression[callee.object.name='assert'][callee.property.name='throws'][arguments.1.type='Literal']:not([arguments.1.regex])"
       message: "Use an object as second argument of assert.throws()"
     - selector: "CallExpression[callee.object.name='assert'][callee.property.name='throws'][arguments.length<2]"

test/.eslintrc.yaml

@@ -23,10 +23,14 @@ rules:
   no-restricted-syntax:
     # Config copied from .eslintrc.js
     - error
+    - selector: "CallExpression[callee.object.name='assert'][callee.property.name='deepStrictEqual'][arguments.2.type='Literal']"
+      message: "Do not use a literal for the third argument of assert.deepStrictEqual()"
     - selector: "CallExpression[callee.object.name='assert'][callee.property.name='doesNotThrow']"
       message: "Please replace `assert.doesNotThrow()` and add a comment next to the code instead."
     - selector: "CallExpression[callee.object.name='assert'][callee.property.name='rejects'][arguments.length<2]"
       message: "assert.rejects() must be invoked with at least two arguments."
+    - selector: "CallExpression[callee.object.name='assert'][callee.property.name='strictEqual'][arguments.2.type='Literal']"
+      message: "Do not use a literal for the third argument of assert.strictEqual()"
     - selector: "CallExpression[callee.object.name='assert'][callee.property.name='throws'][arguments.1.type='Literal']:not([arguments.1.regex])"
       message: "Use an object as second argument of assert.throws()"
     - selector: "CallExpression[callee.object.name='assert'][callee.property.name='throws'][arguments.length<2]"

test/parallel/test-timers-same-timeout-wrong-list-deleted.js

@@ -37,7 +37,7 @@ const handle1 = setTimeout(common.mustCall(function() {
 
         // Make sure our clearTimeout succeeded. One timer finished and
         // the other was canceled, so none should be active.
-        assert.strictEqual(activeTimers.length, 0, 'Timers remain.');
+        assert.strictEqual(activeTimers.length, 0);
       }));
     }));
   }), 1);
@@ -53,11 +53,9 @@ const handle1 = setTimeout(common.mustCall(function() {
 
   // Make sure our clearTimeout succeeded. One timer finished and
   // the other was canceled, so none should be active.
-  assert.strictEqual(activeTimers.length, 3,
-                     'There should be 3 timers in the list.');
+  assert.strictEqual(activeTimers.length, 3);
   assert(shortTimer instanceof Timer, 'The shorter timer is not in the list.');
-  assert.strictEqual(longTimers.length, 2,
-                     'Both longer timers should be in the list.');
+  assert.strictEqual(longTimers.length, 2);
 
   // When this callback completes, `listOnTimeout` should now look at the
   // correct list and refrain from removing the new TIMEOUT list which

test/parallel/test-timers-unref-reuse-no-exposed-list.js

@@ -4,11 +4,9 @@ require('../common');
 const assert = require('assert');
 
 const timer1 = setTimeout(() => {}, 1).unref();
-assert.strictEqual(timer1._handle._list, undefined,
-                   'timer1._handle._list should be undefined');
+assert.strictEqual(timer1._handle._list, undefined);
 
 // Check that everything works even if the handle was not re-used.
 setTimeout(() => {}, 1);
 const timer2 = setTimeout(() => {}, 1).unref();
-assert.strictEqual(timer2._handle._list, undefined,
-                   'timer2._handle._list should be undefined');
+assert.strictEqual(timer2._handle._list, undefined);