lib: correct error.errno to always be numeric

Historically `error.errno` of system errors thrown by Node.js
can sometimes be the same as `err.code`, which are string
representations of the error numbers. This is useless and incorrect,
and results in an information loss for users since then they
will have to resort to something like
`process.binding('uv'[`UV_${errno}`])` to get to the numeric
error codes.

This patch corrects this behavior by always setting `error.errno`
to be negative numbers. For fabricated errors like `ENOTFOUND`,
`error.errno` is now undefined since there is no numeric equivalent
for them anyway. For c-ares errors, `error.errno` is now undefined
because the numeric representations (negated) can be in conflict
with libuv error codes - this is fine since numeric codes was
not available for c-ares errors anyway.

Users can use the public API `util.getSystemErrorName(errno)`
to retrieve string codes for these numbers.

PR-URL: https://github.com/nodejs/node/pull/28140
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>

1 files changed, 40 insertions, 20 deletions

diff --git a/test/internet/test-dns.js b/test/internet/test-dns.js
index 3d331fd196..c74acc50dd 100644
--- a/test/internet/test-dns.js
+++ b/test/internet/test-dns.js
@@ -24,6 +24,7 @@
 const common = require('../common');
 const { addresses } = require('../common/internet');
 const { internalBinding } = require('internal/test/binding');
+const { getSystemErrorName } = require('util');
 const assert = require('assert');
 const dns = require('dns');
 const net = require('net');
@@ -71,7 +72,10 @@ function checkWrap(req) {
 TEST(function test_reverse_bogus(done) {
   dnsPromises.reverse('bogus ip')
     .then(common.mustNotCall())
-    .catch(common.expectsError({ errno: 'EINVAL' }));
+    .catch(common.mustCall((err) => {
+      assert.strictEqual(err.code, 'EINVAL');
+      assert.strictEqual(getSystemErrorName(err.errno), 'EINVAL');
+    }));
 
   assert.throws(() => {
     dns.reverse('bogus ip', common.mustNotCall());
@@ -161,11 +165,13 @@ TEST(async function test_resolveMx(done) {
 TEST(function test_resolveMx_failure(done) {
   dnsPromises.resolveMx(addresses.INVALID_HOST)
     .then(common.mustNotCall())
-    .catch(common.expectsError({ errno: 'ENOTFOUND' }));
+    .catch(common.mustCall((err) => {
+      assert.strictEqual(err.code, 'ENOTFOUND');
+    }));
 
   const req = dns.resolveMx(addresses.INVALID_HOST, function(err, result) {
     assert.ok(err instanceof Error);
-    assert.strictEqual(err.errno, 'ENOTFOUND');
+    assert.strictEqual(err.code, 'ENOTFOUND');
 
     assert.strictEqual(result, undefined);
 
@@ -199,11 +205,13 @@ TEST(async function test_resolveNs(done) {
 TEST(function test_resolveNs_failure(done) {
   dnsPromises.resolveNs(addresses.INVALID_HOST)
     .then(common.mustNotCall())
-    .catch(common.expectsError({ errno: 'ENOTFOUND' }));
+    .catch(common.mustCall((err) => {
+      assert.strictEqual(err.code, 'ENOTFOUND');
+    }));
 
   const req = dns.resolveNs(addresses.INVALID_HOST, function(err, result) {
     assert.ok(err instanceof Error);
-    assert.strictEqual(err.errno, 'ENOTFOUND');
+    assert.strictEqual(err.code, 'ENOTFOUND');
 
     assert.strictEqual(result, undefined);
 
@@ -241,11 +249,13 @@ TEST(async function test_resolveSrv(done) {
 TEST(function test_resolveSrv_failure(done) {
   dnsPromises.resolveSrv(addresses.INVALID_HOST)
     .then(common.mustNotCall())
-    .catch(common.expectsError({ errno: 'ENOTFOUND' }));
+    .catch(common.mustCall((err) => {
+      assert.strictEqual(err.code, 'ENOTFOUND');
+    }));
 
   const req = dns.resolveSrv(addresses.INVALID_HOST, function(err, result) {
     assert.ok(err instanceof Error);
-    assert.strictEqual(err.errno, 'ENOTFOUND');
+    assert.strictEqual(err.code, 'ENOTFOUND');
 
     assert.strictEqual(result, undefined);
 
@@ -279,11 +289,13 @@ TEST(async function test_resolvePtr(done) {
 TEST(function test_resolvePtr_failure(done) {
   dnsPromises.resolvePtr(addresses.INVALID_HOST)
     .then(common.mustNotCall())
-    .catch(common.expectsError({ errno: 'ENOTFOUND' }));
+    .catch(common.mustCall((err) => {
+      assert.strictEqual(err.code, 'ENOTFOUND');
+    }));
 
   const req = dns.resolvePtr(addresses.INVALID_HOST, function(err, result) {
     assert.ok(err instanceof Error);
-    assert.strictEqual(err.errno, 'ENOTFOUND');
+    assert.strictEqual(err.code, 'ENOTFOUND');
 
     assert.strictEqual(result, undefined);
 
@@ -322,11 +334,13 @@ TEST(async function test_resolveNaptr(done) {
 TEST(function test_resolveNaptr_failure(done) {
   dnsPromises.resolveNaptr(addresses.INVALID_HOST)
     .then(common.mustNotCall())
-    .catch(common.expectsError({ errno: 'ENOTFOUND' }));
+    .catch(common.mustCall((err) => {
+      assert.strictEqual(err.code, 'ENOTFOUND');
+    }));
 
   const req = dns.resolveNaptr(addresses.INVALID_HOST, function(err, result) {
     assert.ok(err instanceof Error);
-    assert.strictEqual(err.errno, 'ENOTFOUND');
+    assert.strictEqual(err.code, 'ENOTFOUND');
 
     assert.strictEqual(result, undefined);
 
@@ -369,11 +383,13 @@ TEST(async function test_resolveSoa(done) {
 TEST(function test_resolveSoa_failure(done) {
   dnsPromises.resolveSoa(addresses.INVALID_HOST)
     .then(common.mustNotCall())
-    .catch(common.expectsError({ errno: 'ENOTFOUND' }));
+    .catch(common.mustCall((err) => {
+      assert.strictEqual(err.code, 'ENOTFOUND');
+    }));
 
   const req = dns.resolveSoa(addresses.INVALID_HOST, function(err, result) {
     assert.ok(err instanceof Error);
-    assert.strictEqual(err.errno, 'ENOTFOUND');
+    assert.strictEqual(err.code, 'ENOTFOUND');
 
     assert.strictEqual(result, undefined);
 
@@ -407,11 +423,13 @@ TEST(async function test_resolveCname(done) {
 TEST(function test_resolveCname_failure(done) {
   dnsPromises.resolveCname(addresses.INVALID_HOST)
     .then(common.mustNotCall())
-    .catch(common.expectsError({ errno: 'ENOTFOUND' }));
+    .catch(common.mustCall((err) => {
+      assert.strictEqual(err.code, 'ENOTFOUND');
+    }));
 
   const req = dns.resolveCname(addresses.INVALID_HOST, function(err, result) {
     assert.ok(err instanceof Error);
-    assert.strictEqual(err.errno, 'ENOTFOUND');
+    assert.strictEqual(err.code, 'ENOTFOUND');
 
     assert.strictEqual(result, undefined);
 
@@ -443,11 +461,13 @@ TEST(async function test_resolveTxt(done) {
 TEST(function test_resolveTxt_failure(done) {
   dnsPromises.resolveTxt(addresses.INVALID_HOST)
     .then(common.mustNotCall())
-    .catch(common.expectsError({ errno: 'ENOTFOUND' }));
+    .catch(common.mustCall((err) => {
+      assert.strictEqual(err.code, 'ENOTFOUND');
+    }));
 
   const req = dns.resolveTxt(addresses.INVALID_HOST, function(err, result) {
     assert.ok(err instanceof Error);
-    assert.strictEqual(err.errno, 'ENOTFOUND');
+    assert.strictEqual(err.code, 'ENOTFOUND');
 
     assert.strictEqual(result, undefined);
 
@@ -461,12 +481,12 @@ TEST(function test_resolveTxt_failure(done) {
 TEST(function test_lookup_failure(done) {
   dnsPromises.lookup(addresses.INVALID_HOST, 4)
     .then(common.mustNotCall())
-    .catch(common.expectsError({ errno: dns.NOTFOUND }));
+    .catch(common.expectsError({ code: dns.NOTFOUND }));
 
   const req = dns.lookup(addresses.INVALID_HOST, 4, (err) => {
     assert.ok(err instanceof Error);
-    assert.strictEqual(err.errno, dns.NOTFOUND);
-    assert.strictEqual(err.errno, 'ENOTFOUND');
+    assert.strictEqual(err.code, dns.NOTFOUND);
+    assert.strictEqual(err.code, 'ENOTFOUND');
     assert.ok(!/ENOENT/.test(err.message));
     assert.ok(err.message.includes(addresses.INVALID_HOST));