test: fix argument computation in embedtest

There were a few bugs in the original test that went unnoticed
because with the bug the test did not actually get run anymore.
This patch fixes the argument computation by accounting filtering
of the arguments, and uses spawnSyncAndExit{WithoutError} in
the test to enable better logging when the test fails.

PR-URL: #49506
Fixes: #49501
Reviewed-By: Darshan Sen <raisinten@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

test/embedding/embedtest.cc

@@ -89,7 +89,7 @@ int RunNodeInstance(MultiIsolatePlatform* platform,
       snapshot_as_file = true;
     } else if (arg == "--embedder-snapshot-blob") {
       assert(i + 1 < args.size());
-      snapshot_blob_path = args[i + i];
+      snapshot_blob_path = args[i + 1];
       i++;
     } else {
       filtered_args.push_back(arg);
@@ -121,9 +121,10 @@ int RunNodeInstance(MultiIsolatePlatform* platform,
 
   if (is_building_snapshot) {
     // It contains at least the binary path, the code to snapshot,
-    // and --embedder-snapshot-create. Insert an anonymous filename
-    // as process.argv[1].
-    assert(filtered_args.size() >= 3);
+    // and --embedder-snapshot-create (which is filtered, so at least
+    // 2 arguments should remain after filtering).
+    assert(filtered_args.size() >= 2);
+    // Insert an anonymous filename as process.argv[1].
     filtered_args.insert(filtered_args.begin() + 1,
                          node::GetAnonymousMainPath());
   }
@@ -153,19 +154,26 @@ int RunNodeInstance(MultiIsolatePlatform* platform,
     Context::Scope context_scope(setup->context());
 
     MaybeLocal<Value> loadenv_ret;
-    if (snapshot) {
+    if (snapshot) {  // Deserializing snapshot
       loadenv_ret = node::LoadEnvironment(env, node::StartExecutionCallback{});
-    } else {
+    } else if (is_building_snapshot) {
+      // Environment created for snapshotting must set process.argv[1] to
+      // the name of the main script, which was inserted above.
       loadenv_ret = node::LoadEnvironment(
           env,
-          // Snapshots do not support userland require()s (yet)
-          "if (!require('v8').startupSnapshot.isBuildingSnapshot()) {"
-          "  const publicRequire ="
-          "    require('module').createRequire(process.cwd() + '/');"
-          "  globalThis.require = publicRequire;"
-          "} else globalThis.require = require;"
+          "const assert = require('assert');"
+          "assert(require('v8').startupSnapshot.isBuildingSnapshot());"
           "globalThis.embedVars = { nön_ascıı: '🏳️‍🌈' };"
+          "globalThis.require = require;"
           "require('vm').runInThisContext(process.argv[2]);");
+    } else {
+      loadenv_ret = node::LoadEnvironment(
+          env,
+          "const publicRequire = require('module').createRequire(process.cwd() "
+          "+ '/');"
+          "globalThis.require = publicRequire;"
+          "globalThis.embedVars = { nön_ascıı: '🏳️‍🌈' };"
+          "require('vm').runInThisContext(process.argv[1]);");
     }
 
     if (loadenv_ret.IsEmpty())  // There has been a JS exception.

test/embedding/test-embedding.js

@@ -3,7 +3,10 @@ const common = require('../common');
 const fixtures = require('../common/fixtures');
 const tmpdir = require('../common/tmpdir');
 const assert = require('assert');
-const child_process = require('child_process');
+const {
+  spawnSyncAndExit,
+  spawnSyncAndExitWithoutError,
+} = require('../common/child_process');
 const path = require('path');
 const fs = require('fs');
 
@@ -21,39 +24,54 @@ function resolveBuiltBinary(bin) {
 
 const binary = resolveBuiltBinary('embedtest');
 
-assert.strictEqual(
-  child_process.spawnSync(binary, ['console.log(42)'])
-    .stdout.toString().trim(),
-  '42');
-
-assert.strictEqual(
-  child_process.spawnSync(binary, ['console.log(embedVars.nön_ascıı)'])
-    .stdout.toString().trim(),
-  '🏳️‍🌈');
-
-assert.strictEqual(
-  child_process.spawnSync(binary, ['console.log(42)'])
-    .stdout.toString().trim(),
-  '42');
+spawnSyncAndExitWithoutError(
+  binary,
+  ['console.log(42)'],
+  {
+    trim: true,
+    stdout: '42',
+  });
 
-assert.strictEqual(
-  child_process.spawnSync(binary, ['throw new Error()']).status,
-  1);
+spawnSyncAndExitWithoutError(
+  binary,
+  ['console.log(embedVars.nön_ascıı)'],
+  {
+    trim: true,
+    stdout: '🏳️‍🌈',
+  });
 
-// Cannot require internals anymore:
-assert.strictEqual(
-  child_process.spawnSync(binary, ['require("lib/internal/test/binding")']).status,
-  1);
+spawnSyncAndExit(
+  binary,
+  ['throw new Error()'],
+  {
+    status: 1,
+    signal: null,
+  });
 
-assert.strictEqual(
-  child_process.spawnSync(binary, ['process.exitCode = 8']).status,
-  8);
+spawnSyncAndExit(
+  binary,
+  ['require("lib/internal/test/binding")'],
+  {
+    status: 1,
+    signal: null,
+  });
 
+spawnSyncAndExit(
+  binary,
+  ['process.exitCode = 8'],
+  {
+    status: 8,
+    signal: null,
+  });
 
 const fixturePath = JSON.stringify(fixtures.path('exit.js'));
-assert.strictEqual(
-  child_process.spawnSync(binary, [`require(${fixturePath})`, 92]).status,
-  92);
+spawnSyncAndExit(
+  binary,
+  [`require(${fixturePath})`, 92],
+  {
+    status: 92,
+    signal: null,
+  });
 
 function getReadFileCodeForPath(path) {
   return `(require("fs").readFileSync(${JSON.stringify(path)}, "utf8"))`;
@@ -64,31 +82,49 @@ for (const extraSnapshotArgs of [[], ['--embedder-snapshot-as-file']]) {
   // readSync + eval since snapshots don't support userland require() (yet)
   const snapshotFixture = fixtures.path('snapshot', 'echo-args.js');
   const blobPath = tmpdir.resolve('embedder-snapshot.blob');
-  const buildSnapshotArgs = [
+  const buildSnapshotExecArgs = [
     `eval(${getReadFileCodeForPath(snapshotFixture)})`, 'arg1', 'arg2',
+  ];
+  const embedTestBuildArgs = [
     '--embedder-snapshot-blob', blobPath, '--embedder-snapshot-create',
     ...extraSnapshotArgs,
   ];
-  const runEmbeddedArgs = [
-    '--embedder-snapshot-blob', blobPath, ...extraSnapshotArgs, 'arg3', 'arg4',
+  const buildSnapshotArgs = [
+    ...buildSnapshotExecArgs,
+    ...embedTestBuildArgs,
+  ];
+
+  const runSnapshotExecArgs = [
+    'arg3', 'arg4',
+  ];
+  const embedTestRunArgs = [
+    '--embedder-snapshot-blob', blobPath,
+    ...extraSnapshotArgs,
+  ];
+  const runSnapshotArgs = [
+    ...runSnapshotExecArgs,
+    ...embedTestRunArgs,
   ];
 
   fs.rmSync(blobPath, { force: true });
-  const child = child_process.spawnSync(binary, [
-    '--', ...buildSnapshotArgs,
-  ], {
-    cwd: tmpdir.path,
-  });
-  if (child.status !== 0) {
-    console.log(child.stderr.toString());
-    console.log(child.stdout.toString());
-  }
-  assert.strictEqual(child.status, 0);
-  const spawnResult = child_process.spawnSync(binary, ['--', ...runEmbeddedArgs]);
-  assert.deepStrictEqual(JSON.parse(spawnResult.stdout), {
-    originalArgv: [binary, ...buildSnapshotArgs],
-    currentArgv: [binary, ...runEmbeddedArgs],
-  });
+  spawnSyncAndExitWithoutError(
+    binary,
+    [ '--', ...buildSnapshotArgs ],
+    { cwd: tmpdir.path },
+    {});
+  spawnSyncAndExitWithoutError(
+    binary,
+    [ '--', ...runSnapshotArgs ],
+    { cwd: tmpdir.path },
+    {
+      stdout(output) {
+        assert.deepStrictEqual(JSON.parse(output), {
+          originalArgv: [binary, '__node_anonymous_main', ...buildSnapshotExecArgs],
+          currentArgv: [binary, ...runSnapshotExecArgs],
+        });
+        return true;
+      },
+    });
 }
 
 // Create workers and vm contexts after deserialization
@@ -99,14 +135,20 @@ for (const extraSnapshotArgs of [[], ['--embedder-snapshot-as-file']]) {
     `eval(${getReadFileCodeForPath(snapshotFixture)})`,
     '--embedder-snapshot-blob', blobPath, '--embedder-snapshot-create',
   ];
+  const runEmbeddedArgs = [
+    '--embedder-snapshot-blob', blobPath,
+  ];
 
   fs.rmSync(blobPath, { force: true });
-  assert.strictEqual(child_process.spawnSync(binary, [
-    '--', ...buildSnapshotArgs,
-  ], {
-    cwd: tmpdir.path,
-  }).status, 0);
-  assert.strictEqual(
-    child_process.spawnSync(binary, ['--', '--embedder-snapshot-blob', blobPath]).status,
-    0);
+
+  spawnSyncAndExitWithoutError(
+    binary,
+    [ '--', ...buildSnapshotArgs ],
+    { cwd: tmpdir.path },
+    {});
+  spawnSyncAndExitWithoutError(
+    binary,
+    [ '--', ...runEmbeddedArgs ],
+    { cwd: tmpdir.path },
+    {});
 }