repl: deprecate unused function convertToContext

lib/repl.js

@@ -1204,7 +1204,9 @@ function regexpEscape(s) {
  * @param {String} cmd The cmd to convert.
  * @return {String} The converted command.
  */
-REPLServer.prototype.convertToContext = function(cmd) {
+// TODO(princejwesley): Remove it prior to v8.0.0 release
+// Reference: https://github.com/nodejs/node/pull/7829
+REPLServer.prototype.convertToContext = util.deprecate(function(cmd) {
   const scopeVar = /^\s*var\s*([_\w\$]+)(.*)$/m;
   const scopeFunc = /^\s*function\s*([_\w\$]+)/;
   var matches;
@@ -1222,7 +1224,7 @@ REPLServer.prototype.convertToContext = function(cmd) {
   }
 
   return cmd;
-};
+}, 'replServer.convertToContext() is deprecated');
 
 function bailOnIllegalToken(parser) {
   return parser._literal === null &&

test/parallel/test-repl-deprecated.js

@@ -0,0 +1,28 @@
+'use strict';
+const common = require('../common');
+const assert = require('assert');
+const repl = require('repl');
+
+const expected = [
+  'replServer.convertToContext() is deprecated'
+];
+
+process.on('warning', common.mustCall((warning) => {
+  assert.strictEqual(warning.name, 'DeprecationWarning');
+  assert.notStrictEqual(expected.indexOf(warning.message), -1,
+                        `unexpected error message: "${warning.message}"`);
+  // Remove a warning message after it is seen so that we guarantee that we get
+  // each message only once.
+  expected.splice(expected.indexOf(warning.message), 1);
+}, expected.length));
+
+// Create a dummy stream that does nothing
+const stream = new common.ArrayStream();
+
+const replServer = repl.start({
+  input: stream,
+  output: stream
+});
+
+const cmd = replServer.convertToContext('var name = "nodejs"');
+assert.strictEqual(cmd, 'self.context.name = "nodejs"');