repl: do not run --eval code if there is none

lib/internal/main/repl.js

@@ -46,10 +46,9 @@ cliRepl.createInternalRepl(process.env, (err, repl) => {
 
 // If user passed '-e' or '--eval' along with `-i` or `--interactive`,
 // evaluate the code in the current context.
-const source = getOptionValue('--eval');
-if (source != null) {
+if (getOptionValue('[has_eval_string]')) {
   evalScript('[eval]',
-             source,
+             getOptionValue('--eval'),
              getOptionValue('--inspect-brk'),
              getOptionValue('--print'));
 }

lib/internal/process/execution.js

@@ -55,6 +55,7 @@ function evalScript(name, body, breakFirstLine, printResult) {
   const { kVmBreakFirstLineSymbol } = require('internal/util');
 
   const cwd = tryGetCwd();
+  const origModule = global.module;  // Set e.g. when called from the REPL.
 
   const module = new CJSModule(name);
   module.filename = path.join(cwd, name);
@@ -79,6 +80,9 @@ function evalScript(name, body, breakFirstLine, printResult) {
     const { kStdout, print } = require('internal/util/print');
     print(kStdout, result);
   }
+
+  if (origModule !== undefined)
+    global.module = origModule;
 }
 
 const exceptionHandlerState = { captureFn: null };

test/parallel/test-repl-cli-eval.js

@@ -0,0 +1,22 @@
+'use strict';
+const common = require('../common');
+const child_process = require('child_process');
+const assert = require('assert');
+
+// Regression test for https://github.com/nodejs/node/issues/27575:
+// module.id === '<repl>' in the REPL.
+
+for (const extraFlags of [[], ['-e', '42']]) {
+  const flags = ['--interactive', ...extraFlags];
+  const proc = child_process.spawn(process.execPath, flags, {
+    stdio: ['pipe', 'pipe', 'inherit']
+  });
+  proc.stdin.write('module.id\n.exit\n');
+
+  let stdout = '';
+  proc.stdout.setEncoding('utf8');
+  proc.stdout.on('data', (chunk) => stdout += chunk);
+  proc.stdout.on('end', common.mustCall(() => {
+    assert(stdout.includes('<repl>'), `stdout: ${stdout}`);
+  }));
+}